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UMI
THE ECOLOGY OF HARLEQUI. DUCKS (HISTRIONICUS HISTRIONICUS) BREEDING IN JASPER NATIONAL PARK,
CANADA
William Andrew Hunt
BSc. University of Alberta 1989
A THESIS SUBMïiTED FI PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE
in the Department of Biological Sciences
@William Hunt 1998
SIMON FRASER UNTVERSITY
March 1998
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Abstract
i studied the ecology of harlequin ducks (His~rionicus histrionicus) breeding in the
Maligne Valley, Jasper National Park, in the Rocky Mountains of Canada, between 1992
and 1995. This study was initiated by Parks Canada after concerns were raised about the
potential impacts of commercial rafting on harlequin ducks on the Maligne River.
Harlequin ducks arrive frorn coastal wintering areas in early April and initially forage
along the Athabasca River. As higher areas become free of snow, harlequin ducks move
up tributaries such as the Maligne River. Regular surveys throughout the Maligne Valley
each year indicate a stable resident population of at least 30-40 adult harlequin ducks,
with additional transient individuals. During May and June some harlequin ducks occupy
territories on the lower Maligne River. Others feed in the larger lakes and in some years
many congregate at a club site at the outlet of Maligne Lake (MLO) into the Maligne
River. Here males are tolerant of other pairs and females feed intensely, gaining body
condition prior to egg laying in late June. It appears that only females which gained
considerable body condition attempted nesting. Most females nest on high alpine
tributaries. Nesting is initiated immediately following peak flows on tributaries. Hens
rear broods on tributaries then move downstream to forage in large lakes, such as
Medicine Lake, in August and September. At higher elevations hens nest later and in
some years these late broods grow faster.
At the Maligne Lake outlet club site the density of the benthic rnacroinvertebrate
larva preyed on by harlequin ducks is especially high, but usage of the site by harlequin
ducks varies greatly between years. Commercial rafting began on the Maligne River in
1986. Rafts launch on the lake and pass through the club site as they enter the river.
Observations showed that the passage of rafts most often caused harlequin ducks to take
flipht. Detailed behavioural observations showed that when rafts were present, harlequin
ducks fed significantly less. Cornparisons with and without rafting disturbance were
confounded b y poten tial seasonal effects, however the diurnal foraging pattern was
clearly depressed during rafting activities while tirne spent flying and out-of-view
increased. Downstreain of the Maligne Lake outlet, harlequin ducks were rarely observed
on the middle Maligne River. This included two very similar river sections, one with
rafting disturbances in July and August and one with no history of commercial rafting and
very little human disturbance of any kind.
Therefore if hens arrive at the breeding areas in May and must gain considerable
body condition to reproduce in June and July, it is essential that hens are not displaced
from preferred foraging areas. However the middle Maligne River downstream of the
Maligne Lake outlet seems to be seldom utilized by breeding harlequin ducks. 1 conclude
that the long term ecological integrity of the Maligne Valley for harlequin ducks requires
that rafts not be allowed to transit the Maligne Lake outlet and commercial rafting
activities should cease by August when broods move downstream to fa11 foraging areas on
Medicine Lake.
ACKNOWLEDGEMENTS
The field work for this research could not have been completed without the hard work,
patience and dedication of the "Duck Crew". Thanks to Tara, Brenda and Alex and
especially to Karen the-survey-machine and Terry the-bug-picker, who put up with me for
three years straight! Ron Ydenberg, Fred Cooke and Ian Goudie, the mernbers of my
cornmittee, al1 visited the field site and provided useful assistance, teaching, and advice.
Finally thanks to the gang at SFU for making my stay there enjoyable and filling me in on
al! the stuff 1 didn't know.
To Laura,
for- putting 2p with me through this long process and
to Andrew
for inspiring me toJinalZy gct it finished!
To Moln and Dad
for ge'elting me interested in this stuflto begrn wiih and
Laurie and Dan
for Zeading the way!
TABLE OF CONTENTS . .
Approval Pagje 11
a . .
Abstract 111
Acknowledgements v
Dedication vi
Table of Contents vii a . .
List of Tables VIU
List of Figures x
CHAPTER ONE - General Introduction 1
CHAPTER TWO - Ecology of Harlequin Ducks in the Maligne Valley,
Jasper National Park. 6
Introduction 6
Methods 7
Results 19
Discussion 64
Summary 71
CHAPTER THREE - Behaviour of Harlequin Ducks at an Undisturbed Club Site 74
Introduction
Methods
Results
Discussion
CHAPTER FOUR - Behaviour of Harlequin Ducks at a Disturbed Club Site
Introduction
Methods
Results
Discussion
CHAPTER FIVE - Commercial Rafting on the Maligne River: Effects and
Impacts on Harlequin Ducks
Literature Cited
vii
LIST OF T B L E S
Table 2.1 - Distribution aiid rafting staius of survey sites establislied dong the Maligne Lake Road in Jasper
Natioiial Park for ille Maligne River survey, 1993 - 1995. 13
Table 2.2 - Diversity and idative abundance of potentid food items for har1equi.n ducks, collected from the
Maligne River, Jasj~er National Park, 1995, using two different sampling techniques; kick smpling and
bloçk settipling (iiiulti-plate sampler). Groups marked with cin X are common to both sampling
teclmiqiies. mie hiomass index is the product of frequency and size cius. 32
Table 2.3 - Nruiibers of malc. fernale, adult and young-of-year hwlequin ducks banded in Jasper National Park,
during 1994 md 1995. 45
Talilc 2.4 - Mcasuremenl of 38 adult females, 34 adult males, 19 young females and 22 young males (some
vslucs of n will be less as some measurement sets of adults were incomplete). Values are means,
braçkets are staiidard deviation, bold lettering indicatites a ~ i g ~ c a n t difference behveen males and
lkmrilcs of tliat agç class (adult p< 0.00 1; young p < 0.05). Males were captured between 10 May and
08 July, wliereas lkmales were captured between 10 May and 06 September. 47
TaMe 2.5 Iniluence of ses. üge, hatcli date, elevation and year eeffects on the m u s of young of year harlequin
ducks (ANOVA. n = 41, rZ = 0.447). 57
Tal~lc 3.1 - Caiegoiies of bcliüviom assigned during instantaneous focal sampling at 30 second Intervais for 30
iiiiniitcs at the Maligne Lake outlet in Juper Nationd Park. Each behaviour was ftrst grouped into one
of îiic iive iiiiun ~ategoxies, then the appropriate sub-category \vas assigned. 78
Table 3.2 - Distribution of' pre-nesting harlequin ducks within the Maligne Lake outlet diuing May and June,
1993. and the distribution of feeding and lotdimg activities wiîiiin the outlet. Zone A is adjacent to
Maligne Lake aiid Zone E defmes the furthesr downstream portion of the Maligne Lake outlet.
81
Table 3.3 - Beliovioius of Iiiirlequin ducks at the Maligne Lake outlet in Jasper National Park in May and June,
1993. Tliese beliaviours were measured using instantmeous focal samphg, at 30 second intervals, for
viii
30 iiiiiiutes (n is the number of sampling periods). Values are expressed as perceritages. asterisks
Uidicxtes ü signiliçant difference between males and females for that behaviour category.
82
Table 3.4 - Variation in geiicrd behaviours of male tuid female harlequin ducks while paired and unpaixed (solo).
Note thül these çiassiîications refer to mate guarding activities during the observation period, and not
iiccessarily the breeding status for the season. 83
Taide 4.1 - Rextions of groups of 1 -7 harlequin ducks to watercraft disturbances during 86 separate interactions
iit iiie Maligne Lakc outlet in Jasper National Park from O 1 to 22 Juiy 1993. Total = 263 interactions
(2 13 iiiales and 5 0 t'eriides). 97
Table 4.2 - Chüiiges in the mean percent of time hulequin ducks devoted to dserent behaviours with the
Maligiic River closed (June) and open (July) to human use in 1993. Results of 277 focal animal
observation sessions at the MLO. 1 recorded behaviours every 30 seconds during each 30 minute
session. Values in brackets are the standard error of the mem. 102
LIST OF FIGURES
Figure 2.1 - Map of the Maligne Valley Study are% Jasper Nationd Park showing river sections as indicated
by liglit bars. 8
Figure 2.2 - Map of MaIigne Valley study ami, Jasper National Park, showing the survey sites used in the
Maligne Itiver Suivey and the area covered by the Maligne Lake s w e y . 14
Figure 2.3 - Map of tlie Maligne Valley study area, Jasper National Park, showing tributaries surveyed for
Iiürlçqtiui duck broods and nests, 1993 - 1995. 17
Figure 2.4 - Seasonal patierns of daily temperature (maximum and rnininiulll) and precipitation within the
Maligne ValIey slridy are% Jasper National Park, 1993 (top) to 1995 (bottom). 20
Figure 2.5 - Montlily mem ( *SE) minimum daily temperature and mean daily precipitation, in the Maligne
Valley. May - Arigust, 1993 - 1995. 2 1
Figure 2.6 - Daily rütes of discharge (m3/s), from May to August, on the lower Maligne River at 6th Bridge (O)
and on thc middle Maligne River at tlie Maligne Lake outlet (+), within the Maligne Valley study area,
Jasper National Park, 1993 -1995. 22
Figure 2.7 - Daily staff guiige reiiding (tlow height, metres) on the middle Maligne River, at the Maligne Lake
outlet and on Evclyn Creek, a tributary, near its confluence with the Maligne River, w i i h Jasper
NationaI Park, 1993 - 1995. 24
Figure 2.8 - Moiiildy rneüii (* SE) stream temperature, from May to July 1993 (shaded), 1994 (solid) and 1995
(open). iileasured ;it the Maligne Lake outlet, Jasper National Park. 25
Figure 2.9 - Dnily abundaiiçc of spawning rainbow trout (Onchorliyncus mykiss), observed daily from Bridge
A at the Maligne Lake outlet, Jasper National Park, during June 1993 - 1995. 27
Figure 2.10 - liclative bionisss estimates of various invertebrate prey available to harlequin ducks foraging at
tlie Maligne Lake outlet, 1993 - 1995. The biomass index is the product of the frequency and size class;
sanipl~s were obtained by kick sampling. 28
Figure 2.1 1 - Moiitlily availability of invertebrate prey for harlequin ducks foraging at the Maligne Lake outlet,
Jasper National Park. Samples were obtained by kick sampling in 1993 (n = IO), 1994 (n = 21), and
1995 (n = 27). 29
Figure 2.12 - Ttie relationsliip between the mean daily abundance of harlequin ducks and the mean prey biomass
i d e s (invertebraie abundance x size class) at the Maligne Lake outlet, in Jasper National Park, May and
June 1993 fo 1995 (p = 0.014). hvertebrate samples are the means of 4 sampling sites per day with
tliree (pooled) kick simples collected at each site. 30
Figure 2.13 - Sigriilicünt downstream gradient of the rnean prey biomass index (invertebrates) measured at three
sites elong the niidde Maligne River, by multi-plate sampling, 1995. Sample locations are the Maligne
Lake oritlet (MLO. i i = IO), Bridge C on the riiiddle Maligne River (MMARi, n = 12) and the upper end
of the Medicine Lake delta (MEDLA, n = 7). Mean PB1 * SE. 3 1
Figure 2.14 - Seasonal diiuiges in the distribution md abundance of harlequin ducks witliin the Maligne Valley,
Jasper N;itiorial Park, observed during weekly surveys of 37 sites along the lower and middle Maligne
River aiid a sunlcy of the perimeter of Maligne Lake from May to mid-September, 1993-1 995.
34
Figure 2.15 - Abundma ol'various classes of harlequin ducks witliin the Maligne Valley, Jasper National Park,
from May to rnid-September, 1993-1995. Results from weekly surveys of 37 sites along the Iower and
iiiiddle Maligne River and a survey of the perhneter of Maligne Lake. The graph showing ''dl harlequin
duçks" iiiçludes observations of 18 unclassitied hürlequin ducks, observed on Medicine Lake, 1994,
weeks 17 and 18. respectively. 35
Figure 2.16 - Seüsond cliaiiges in the abundance of harlequin ducks at four areas within the Maligne Valley,
Jasper National Park, observed during weekly surveys of 37 sites dong the lower Maligne River and
a survey of the peiimeter of Maligne Lake from May to mid-September, 1993 - 1995.
36
Figurc 2.17 - The abundancc of liarlequin ducks observed at the Maligne Lake outiet and Maligne Lake, Jasper
Naiionai Park, eaçh week, from May to July 1993 - 1995. 38
Figure 2.18 - Daily mean abundance of all (+) and female (O) harlequin ducks at the Maligne Lake outlet, Jasper
National Park, lkoiii May to July 1993 - 1995. 39
Figure 2.19 - Abundance ofharlequin ducks ai the Maligne Lake outlet, Jasper National Park, during May, June
ünd July, 1986 ta 1995. Values before 1993 are means of several surveys per month; others are mean
of several siuveys per day. 40
Figurc 2.20 - Body mass of' female harlequin ducks during the breeding season (May - September) 1994 and
1995. Dark circles are non-breeding females and open circles are proportionally larger for hem
sliowiiig signs of breeding. Pre-nesting liens were assiped one increment each for: being püired, brood
patcli dcveloped, open pelvis, and egg in abdomen; brood rearing hem were r d e d by the size of their
brood. 50
Figurc 2.21 - Changes aiid inferred changes in body mass of Iive individual fe~iiale harlequin ducks, 1994
(open) and 1995 (sliaded). Syrnbols represent individuai birds. Liglit lines show possible weight
trqjectory patterns and dark lines show known changes witliin a single year. See text for information
on individual birds. 52
Figure 2.22 - Relationsliip hetween age and mass in male (open circles) and female (shaded circles) young-of-
year Iiarlçquin ducks cüptured in the Maligne Valley, Jasper National Park, 1994 and 1995.
54
Figurc 2.23 - Relationsliip between hatch date (Julian date) and the mass of young-of-year harlequin ducks
relative to tlieir agç. cüptured in the Maligne Vdley, Jasper National Park, during 1994 (shaûed circles)
and 1995 (open çircles). Relative m a s is the residual of the mass : age regression. 55
Figure 2.24 - 'Ilic: rclationsliip between brood elevation and a) estinlated hatch date (Julian date)(n = 19) and b)
the iiiiiss OS individual young, relative to their age (n = 4 l)(the latter values are the residuals of the
rriass:agç regression) within tlie Maligne Valley, Jasper National Park, during sunteys in 1993 (solid
çircles) and capture and banding in 1994 (sliaded circles) and 1995 (open circles). 56
Figure 2.25 - A cornparison of the m u a l timing of environmental variables within the Maligne Valley, in Jasper
National Park. 1993 to 1995. 58
Figurc 2.26 - 'Tirilhg of i1i~iVd and peak abundance of harlequin ducks at the Maligne Lake outlet in Jasper
Nütiond l)ark, relative to the timing of spring nuioff, from 1987 - 1995. Sprhg runoff is the date wIien
tlie tlow rate reaçhed 30m3/s on the lower Mdigne River, and anival date was d e h e d as the first date
wlien more than two liarlequin ducks were present at the outlet. 60
xii
Figure 2.27 - Tiillng of peak abundance of male and female harlequin ducks at the Maligne Lake outiet in Jasper
National Park, relative to the timing of spring runoff, from 1987 to 1995. Spring runoff is the date
wlien ilie ilow rate reached 3Od/s on the lower Maligne River. 6 1
Figure 2.28 - Discliarge r a b on the lower Maligne River, during Miiy and June, when male (A) and female (+)
Iiarlequin ducks wcre most abundant at the Maligne Lake outiet, in Jasper National Park, relative to the
iiiem disçliürge rate (0). Values are weighted means cdculated by summing the product of the number
of duçks present aiici tlie correspondhg discharge rate and then dividing by the total frequency. Error
bars are tlie standml deviation of the mean discharge rate. 63
Figure 3.1 - Miip or the Midigne Lake outlet hi Jasper National Park. 76
Figure 3.2 - Diiirnsl çliaiig~.s in the behaviours of liürlequin ducks at the Maligne Lake outlet, Jasper National
Park, 1993. Tliesc are the results of 103 focal animal sessions ( 30 min. each) conducted between 28
May und 30 Junc. To examine for seasonal effects, tlie data are divided into graphs a) and b), vhicli
cire the sequential50 th percentiles of the data. Diurnd grouphgs are: AM - 0500 - 0900, NOONl =
0900 - 1300, NOON2 = 1300 - 1700, PM1 = 1700 - 2100, a d PM2 =SI00 - 2300. 85
Figure 3.3 - Diilriid çliüiiges in the proportion of lime spent diving by harlequin ducks at the Maligne Lake
outlet, Jasper National Park, 1993. These are the results of 103 focal animal sessions (30 min. each)
conduçted behveen 28 May and 30 June. To examine for seasonai effects, the data are divided into
graplis il) and b), which are the sequentiai 50 th percentiles of the data. D i m a l groupings are: AM - 0500 - 0900, NOONI = 0900 - 1300, NOON2 = 1300 - 1700, PM1 = 1700 - 2100, and PM2 = 2100 - 2300. 86
Figure 3.1 - Diurnal changes in the proportion of time spent Ilying by harlequin diicks ai the Maligne Lake
outlet, Jasper National Park, 1993. These are the results of 103 focal animal sessions ( 30 min. each)
çonduçted betweeii 28 May and 30 June. To examine for seasonal effects, the data are divided into
graplis a) aiid b), wliiçh are the sequentia1 50 th percentiles of the data. Diwnal groupings are: AM - 0500 - 0900, NOONl = 0900 - 1300, NOON2 = 1300 - 1700, PMI = 1700 - 2 100, and PM2 = 2100 - 2300. 87
Figure 4.1 - Tlie total nuinber of commercial whitewater raft trips down the upper-middle section of the Maligne
River in J q e r National Park, fiom May to September, 1986 to 1995. From 1993 to 1995 the middle
seçiiori of tlie Maligne River was cIosed to al1 human use during May and June. 95
xiii
Figure 4.2 - Cliiuiges in sp;iiid distribution of harlequin ducks at the Maligne Lake outlet, Jasper National Park,
recordai during liiking surveys dong tlie first 1.5 km of the outlet area, wiîhout (CLOSED) and with
(OPEN) liiunan disturbance h m commercial whitewater rafting. Zone A is adjacent to Maligne Lake
and coiisecutive zones are dowastream. Al1 distribution shifts were significant (G-test, p c 0.05).
100
Figure 4.3 - Climges in distribution of loafhg and foraging harlequin ducks at the Maligne Lake outlet, Jasper
National Park, rcçorded during hiking surveys dong the fmt 1.5 km of the outlet area, without
(CLOSED) tuid witli (OPEN) Iiuman disturbance from commercial whitewater rafting. Zone A is
acijaçent to Maligriç Lake and consecutive zones are downstrem. All distribution shifts were signifïcant
(G-test. p < 0.05). 10 1
Figurc 4.4 - Seasond cliangcs in the behaviours of liarlequin ducks at the Maligne Lake outlet, Jasper National
Park. Tliese are the results of 277,30 min. instantaneous focal animal observation session conducted
i'rotii 1 1 June to O 1 August, 1993. The white bars are ille sequential 50 th percenaes of the "river
closed" data from June and the black bars sue that from "river open" data from July and August.
103
Figure 4.5 - Diurnal changes in the proportion of t h e spent diving by harlequin ducks at the Maligne Lake
outlet, Jasper Nationd Park. These are the results of 277,30 min. instantaneous focal interval sessions
çonduçted l'rom 1 1 June to 01 August, 1993. Graphs a) and b) are the sequentid 50 th percentiles of
rlie "river çlosed"data from June and graphs c) and d) are the sequential50 th percentiles of the "river
oyen"data from Jiily m i August. Diumal groupings are: AM = 0500 - 0900, NOONl = 0900 - 1300,
NOON2 = 1300 - 1700, PM1 = 1700 - 2 100, and PM2 = 2 100 - 2300. Commercial rafthg occurred
during the two noon periods. 105
Figure 4.6 - Diunial dianges in the proportion of time spent flying by harlequin ducks at the Maligne Lake
outlet, J~isper Nationd Park. These are the results of 277,30 min. instantaneous focal interval sessions
çonductcd liom 1 1 June to 01 August, 1993. Grtaplis a) and b) are the sequentialS0 th percentiles of
the "river ç1osed"data from June and graphs c) and d) are the sequential50 th percentiles of the "river
opeii"data fiom July aiid August. Diurnal groupings are: AM = O500 - 0900, NOONl = 0900 - 1300,
NOON2 = 1300 - 1700, PMI = 1700, - 2100, and PM2 = 2 100 - 2300. Commercial rafting occwred
during tlie two noon periods. 1 06
xiv
Figurt! 4.7 - Ditlinal cliangcs in the beliaviours of harlequin ducks at the Maligne Lake outlet, Jasper National
Park. 'Iliese are thc results of 277,3O min. insiantmeous focal interval sessions conducted from 1 1 June
10 O 1 August, 1993. Graphs a) md b) are the sequential50 th percentiles of the "river c1osed"data from
June and graplis ç) and d) are the sequentid50 01 percentiles of the "river open9'data from July and
August. Diurnal groupings are: AM = 0500 - 0900, NOONl = 0900 - 1300, NOON2 = 1300 - 1700,
PM 1 = 1700 - 2 100, and PM2 = 2 100 - 2300. Commercial riifting occurred during the two noon
periods. 107
Figure 4.8 - Pcck raies 01' rcsting male harlequin ducks at the Maligne Lake outlet, Jasper National Park. Data
were çoltected More and after rafting disturbances in June and July, 1995. Peek rate does not
açcur;ifeIy refleçt vigilance as mmaximurn peak rate is achieved at only 50% of maximum vigilance.
111
CHAPTER ONE
GENERAL INTRODUCTION
Harlequin ducks (Histrionicus hislrionicus) winter in coastal environrnents and
migrate inland to breed along fast-flowing rivers. The harlequin duck is the only species
of duck in the northern hernisphere occupying this "whitewater" niche. Similarly adapted
species include the blue duck (Hymenolaimus malacorhynchos) of New Zealand, the
African black duck (Atlas sparsa), Salavadori's duck (Savadorina waigiuensis) of New
Guinea. and the torrent duck (Uerganelta armafa) of South America. Unlike the
harlequin duck, al! other whitewater ducks are permanent river residents and do not
winter on the Coast. Several of these species are experiencing serious declines due to
various forms of human induced habitat degradation (Eldridge 1986, Veltrnan and
Williams, 1990).
Global Distri bution
In North America, harlequin ducks occur in two geographicaliy isolated
populations. The Pacific population occupies the largest range including eastern Asia,
mountains of eastern Siberia, Aleutian Islands, British Columbia, Alberta, Yukon and the
northwestern States. The Atlantic harlequin duck occurs Newfoundland, Labrador,
Quebec, the Maritime Provinces and coastal northeastern United States (Madge and Burn
1988). Two other isolated populations, in Iceland and Southern Greenland, are often
included as part of the Atlantic population, and harlequin ducks which bred in Hudson
Bay in eastern Canada have recently been discovered wintering off Greenland (Robert et
al. 1997).
Stattis in North America
The Atlantic population was closed to hunting in 1989. In 1990 the Cornmittee on
the Status of Endangered Wildiife in Canada listed the eastern population of harlequin
ducks as an endangered species as less than a thousand individuals may remain in Atlantic
Canada (Goudie 199 1). Since then, Morneau and Decairie (1994), reported a maximum
count of 377 harlequin ducks on breeding ranges in the Great Whale watershed of Quebec
during an environmental assessrnent for the proposed James Bay II hydroelectric project.
In 199 1 , the United States government recognized the harlequin duck as a C2 candidate,
meaning that more data are required to list it as an endangered or threatened species.
The Pacific population is much larger (approximately 100,000 - 200,000 in Nonh
America), though reliable population estimates are difficult (Cassirer el al. 1993). The
range of this population extends throughout the northern hernisphere of the Pacific Rim.
Virtuaily nothing is known about populations on the eastern coasts of Asia. Throughout
western Nonh America, harlequin ducks are classified as a migratory game bird, with bag
limits of four per day in Washington, Oregon, and California, six per day in British
Columbia, and 15 per day in Alaska. Despite this, several states have recognized
harlequin ducks as a species requiring special management. These include Washington
(priority habitat species), Idaho and Montana (species of special concern), and Oregon
(state sensitive species) (Cassirer et al. 1993). In British Columbia the Canadian Wildlife
Service has recommended the harlequin duck as an indicator of pristine ecosysterns in the
Tatshenshini proposed wilderness area (Cassirer ei al. 1993).
Breeding Ecology
The breeding ecology of harlequin ducks has been investigated in Iceland
(Bengtson 1966, 1972, and Bengtson and Ulfstrand 1971) and in the western Nonh
America, (e.g. Wyonti~rgc Wallen 1987, 1 992, Idaho: Cassirer and Groves 199 1, Cassirer
B I al. 1993, Wmhington: Schirato and Sharpe 1992, Montana: Kuchel 1977, Diamond
and Finnegan 1993, Markum 1990, Ashley 1994a. 1994b, 1995, Reichel et al. 1997,
Alberia: Clarkson 1992, Hunt and Clarkson 1993, Hunt 1993, Smith 1996, British
C'olirmhicz: Breault and Savard 199 1, and Afczskn: Dzinbal 1982, Dzinbal and Jarvis 1982,
Crowley 1993, Zwiefel hofer 1994). Harlequi n ducks breed throughout the Rocky
Mountains, and are present on mountain lakes and rivers from May to September (Wallen
1987). Before nesting, males actively defend a 'mobile territory' around their mate, while
the fernales focus on feeding (Inglis et al. 1991). Benthic invertebrate larvae account for
most of the diet while on breeding ranges, although harlequin ducks forage on fish roe
opportunistically (Bengtson 1966, 1972). Several researchers have linked harlequin duck
productivity and habitat selection to macroinvertebrate density (e.g., Bengtson and
Ulfstrand 197 1). W ith the exception of pairs breeding near coastal regions, males leave
the breeding ranges in luly, abandoning females just as they begin incubating, and the
males gather at coastal moulting sites. Female harlequin ducks nest only once per season
(Bengtson 1972). When this research began, the literature provided little information on
nesting habitat or behaviour and there were only two nest records frorn Alberta. D. A.
Boag, reported that in Iune 1963, a nest was found along the Sheep River, Kananaskis
Country, located under a juniper on a rocky cliff face next to the river (Wisely 1979). R.
Richards discovered a harlequin duck nest in the upper alpine section of Evelyn Creek,
Jasper National Park, under dense willows (Ruddy, pers. comm. 1992). In Iceland, each
clutch typically contained six eggs, with a laying interval of two days and required 28
days incubation (Bengtson 1972). Females raise their young in slower sections of rivers
and in lakes, and sometimes abandon broods in September to return to coastal moulting
sites (Wallen 1987, Cassirer and Groves 199 1). Ducklings fledge at 42 - 62 days and
migrate to the coast in Septernber and October (Cassirer and Groves 1991, Bengtson
1972).
Threats
Habitat loss is the greatest threat to PacifÏc harlequin ducks. In Canada, resource
extraction (logging, mining, and oil and gas extraction), pollution, development,
hydroelectric projects. and recreational pressure accounts for most of this habitat loss.
The latter is the greatest concern in Canada's National Parks, where other impacts are
minimized. Many researchers report that harlequin duck abundance is negatively
correlated to huinan disturbance and may contribute to low recruitrnent ( e g , Bengtson
1972. Kuchel 1977, and Wallen 1987, Ashley 1994).
The Situation in Jasper National Park
In 1990, V. Schelhas, a resident of Jasper, informed Parks Canada that the number
of harlequin ducks gathering at the Maligne Lake outlet (MLO) each spring, had declined
over the last five years. Schelhas based this on surveys of the ML0 during May through
July, from 1986 to 1990. Historical records and park biophysical survey data confirm that
this area was an important feeding area for many pre-nesting harlequin ducks (Holroyd
and Karasiuk 1977, Clarkson 1992). Schelhas felt the decline in harlequin duck was due
to increased disturbance from the introduction of commercial river rafting in 1986.
The rapid growth in commercial rafting on the Maligne River adds support to
Schelhas' theory. During the decline in harlequin ducks at the ML0 (1986 - 1992)
commercial rafting on the Maligne River increased from a single Company, running 4 0
rafts trips in 1986. to three companies mnning > 1600 raft trips in 199 1. Rafting occurred
from June to August or September each year. Hunt (1994) found a significant negative
relationship between the mean monthly abundance of pre-nesting harlequin ducks at the
ML0 and the total number of commercial rafts travelling through this area during June
and July. In Montana (Ashley 1994, Diarnond and Finnegan 1993, and Reichel and
Genter 1 993). Washington (Shirato pers. corn. 1994), Idaho (Cassirer and Groves 199 l),
British Columbia (Hunt and Clarkson 1993), and Wyoming (McEneaney 1994)
researchers identified water-oriented recreational activities (e.g. boating, fishing, and
walking stream banks) as having a negative effect on breeding harlequin ducks:
Parks Canada managers were concemed that disturbing or displacing harlequin
ducks at the ML0 might negatively affect reproductive success and result in local
extirpation of harlequin ducks. Therefore, in 1993 these managers closed the mid-
Maligne River and the land surrounding the ML0 to al1 human use during May and June.
Closing the river in June restricted the activities of three commercial river rafting
companies. who launched a legal suit and are presently pursuing financial compensation
from Parks Canada. Park managers confirrned that some form of seasonal river closure
CHAPTER TWO
ECOLOGY OF IIARLEQULN DUCKS IN THE MALIGNE VALLEY,
JASPER NATIONAL PA-
INTRODUCTION
Compared to most other waterfowl, little research has been done on the breeding
ecology of harlequin ducks. Bengtson (1966) wrote the definitive work on harlequin duck
ecology based on his research on the River Laxa, in northem Iceland. This population
offers a rare research opportunity, as up to 50 pairs of harlequin duck concentrate at this
site during the breeding season. Bengtson called this concentration a "club" and
described it as a "public loafing spot" where birds are generally tolerant of each other
although paired males defend their mates. However, in areas of lower density, breeding
birds display territorial behaviours associated with a certain section of stream (Bengtson
1966). Bengtson (1966, 1972) documented various aspects of the species ecology
including a diurnal feeding pattern with peak feeding occurring at 1800 h and 0600 h.
Bengtson and Ulfstrand (1971) showed that food availability directly affected
reproductive success. Inglis et al. (1989) documented the pre-nesting behaviour and time
budgets of harlequin duck on the River Laxa.
Many researchers have investigated the breeding ecology of harlequin ducks in the
United States but this study reports the first research into breeding ecology of harlequin
ducks in Canada. Cassirer (et al. 1993) wrote a thorough review of the statu of harlequin
ducks in North America. Goudie (1991) identified the decline in the eastern population of
Ilarlequin ducks and spearheaded its listing as a COSEWIC endangered species in 1990.
Breault and Savard (1 991) reviewed the distribution and ecology of harlequin ducks in
British Columbia and identified a poor understanding of distribution, habitat
requirements, and reproductive biology as the most serious management problem facing
the harlequin duck.
Within Alberta, virtually nothing was known about the distribution, abundance
and habitat use of harlequin ducks (Clarkson 1992). Other than Schelhas' surveys at the
ML0 (see Chapter 1 ) the only available data are from general wildlife reporting systems
and anecdotal records (Hunt and Clarkson 1993). River and lake surveys, conducted
throughout Jasper National Park (.JNP) in 199 1 identified the Maligne Valley as having
the highest concentration of harlequin duck in JNP (Clarkson 1992). In the Maligne
Valley, the Maligne Lake outlet (MLO) was recognized as an area of unique importance.
The ML0 is the only known "club" site in Canada; the only other reported "club" in
North Arnerica is at the LeHardy Rapids in Yellowstone National Park (McEneaney
1 994).
In this chapter 1 describe my research into the ecology of the harlequin duck in the
Maligne Valley during the breeding season. My objective is to develop a general picture
of harlequin duck usage of the valley to provide a context for questions raised about
possible confl icts between harlequin ducks and commercial whitewater rafting (Chapter
4).
METHODS
Study Area
1 conducted the study in the Maligne Valley watershed, within Jasper National
Park, Alberta from mid-May to mid-September, 1993 to 1995. In 1992, I conducted
various preliminary investigations, and developed survey techniques for harlequin ducks
within the Maligne Valley (Hunt 1994). In 1993, 1 began the first year of intensive
research and used rnany survey techniques developed in 1992.
The Maligne River, a second order Stream, originates in the eastern slopes of the
Canadian Rockies and flows northwest to converge with the Athabasca River which flows
northeast toward the Arctic Ocean as part of the greater Mackenzie Watershed. The
Maligne River can be divided into three distinct sections: the upper Maligne River. which
includes al1 areas upstream of Maligne Lake, the middle Maligne River, from Maligne
Lake downstream to Medicine Lake, and the lower Maligne River, from Medicine Lake
downstreani to the confluence with the Athabasca River (Fig. 2.1).
Maligne River
Big Bend
Athabasca River
Lower
Figure 2.1 - Map of the Maligne Valley study area, Jasper National Park, showing river sections as indicated by light bars (1 cim = 3.8 km).
The upper Maligne River originates at an elevation of 2400 m, and is the only
section inaccessible by road. Maligne Lake is the largest water body in MP
(approximately 22 km long and up to 2 km wide) and acts as a settling pond for glacial
silt transported from its tributaries. Maligne Lake receives high Ievels of human use as it
is the final destination of the Maligne Lake Road (a major scenic corridor in JNP) and
Spirit Island, on Maligne Lake, is a world famous tourist attraction. Several large diesel
tour boats m i s e the lower (northern) basin of Maligne Lake throughout the summer.
Other developments near the ML0 include a restaurant and gift shop, sewage lagoon,
canoe rentals, guided rafting, fishing and horseback riding, several parking lots, a Warden
Station, a network of hiking trails and several docks and boat launches.
At the MLO, (1 18' 40' W, 52' 43 N) water, now almost silt-free, leaves the lake
to descend rapidly through the middle Maligne River and enters Medicine Lake through a
braided grave1 delta. The middle Maligne River and the lower Maligne River are closely
parallelled by a paved road. The top 9 km of the middle Maligne River (from ML0 to Big
Bend) is used by recreational and commercial boaters, but because of a difficult section of
rapids (CLASS V+), the lower portion is seldom paddled, and is not open to commercial
use.
At Medicine Lake, the flow is dismpted as the entire river goes underground
through a karst sinkhole. Medicine Lake slowly fills throughout the summer, as the flow
rate of the middle Maligne River exceeds the underground drainage rate of the karst
sinkhole. During exceptional years, Medicine Lake overfills its banks, and flows through
the valley bottom to unite with the lower Maligne River. Normally the lower Maligne
River relies on water from its tributaries and from a partial resurgence of the underground
stream about 1 km downstream of Medicine Lake. From here, the lower Maligne River
descends gradually, until dropping through two canyons approximately 3.5 km apart. The
section upstream of the lower canyon is too small for boaters and receives very little
human use. The lower canyon has been highly developed as a tourist attraction with a
network of trails connected by five footbridges. Below the Maligne Canyon, the river is
much larger, and descends graduaily to meet the Athabasca River (1,100 m). This last
section is used frequently by recreational paddlers, hikers, and anglen.
Environmental variables
1 rnonitored many variables throughout the Maligne Valley to detect which
factors were linked to annual variations in harlequin duck phenology, habitat use, and
productivity.
1 recorded weather data daily at 0800 h at the Maligne Lake Warden Station
throughout the study including: maximum, minimum, and present temperature (OC),
relative humidity (%), new precipitation (mm), and ranked estimates of wind-speed and
cloud.
An automated stream flow recorder was installed in 1992 at Bridge C on the
Maligne River, upstream of Medicine Lake and data were collected from this flow
recorder throughout this study. An existing strearn flow recorder on the lower Maligne
River, at 6th bridge, does not accurately reflect the flow regirne of the middle Maligne
River as it is downstream of the Medicine Lake sinkhole. However, for cornparison, I
obtained stream fiow data (flow heights (m), and discharge (m3/s)), collected at this lower
elevation flow recorder (1 986 to 1999, from Water Surveys Branch of Environment
Canada.
I also installed several staff gauges in 1992: one at Bridge A (to record the flow
height at the MLO); a second at the Evelyn Creek Bridge, on the Maligne Lake road, to
record water levels on an alpine tributary, and a third at Bridge C , as required for the
automated strearn-flow recorder. Researchers recorded water levels and an estimate of
relative turbidity (O = clear; 4 = very turbid) at these three staff gauges each morning
during the study. Researchers measured stream temperature at the ML0 by submerging a
thermometer, midstream, for several minutes, and recording the temperature to the nearest
0.5 "C.
In 1994 and 1995 we recorded the date when Maligne Lake became ice free. This
is usually a rapid event (c 3 d). 1 attempted to find records of ice-out dates for previous
years for which we there were data on harlequin duck abundance at the MLO; these
included 1976, 1977, and 1986 to 1993.
To assess whether harlequin duck concentrations at the ML0 were correlated with
spawning activity we counted the number of spawning rainbow trout (Onchorhynctrs
mykiss), visible from, and within five metres of, either side of the ML0 bridge, each
morning during June of each year.
In 1994 and 1995, we sarnpled the diversity and relative abundance of benthic
macroinvertebrates at the ML0 by collecting 'kick' sarnples at two week intervals. 1
selected this method because the substrates at the ML0 were too large to allow effective
sampling with area sarnplers such as the Hess or Serber samplers and harlequin ducks
typically were not feeding in shallow areas or finer substrates. To collect samples the
researcher waded out into the current and kicked the substrate, within an approximate 1
m2 area, for 2 min while holding a dip net (45 cm diameter), approximately 40 cm
downstream, to collect the invertebrates as they washed off the substrate. We sampled
four different sites within the MLO, collecting three kick samples at each site. In 1993,
we sampled invertebrates only twice during the season: 29 June (6 samples) and 27 July
(4 samples).
To obtain more quantitative results, in 1995 I developed a rnodified, multi-plate,
sampling technique. 1 used floral patterned cinder blocks (approx. 30 x 30 x 15 cm) as a
substrate, provid ing various micro-site types within the many surfaces, while maintaining
a consistent sampling area. We placed three cinder blocks on the benthos at each of three
sites along the middle Maligne River: MLO, Bridge C (5 km downstream of MLO), and
the upper portion of the Medicine Lake delta (16 km downstream of MLO). A section of
rope, tied to a float, allowed us to relocate and recover blocks. We installed the blocks on
20 May 1995. and sampled them approximately every three weeks (1 2 lune, 05 July, 26
July and 16 Aug.). To collect invertebrates, we plunged the block several times in the
current, while holding a dip-net downstream of the block, until it appeared that al1
invertebrates had been washed off.
We preserved samples in 85% ethanol, sorted sarnples by hand using a dissecting
microscope, and keyed out invertebrates to families following Clifford (1 99 1). Some
specimens could only be keyed to subclass or order (Annelida, Pelecypoda, Hinindinea,
and salmonid eggs). We assigned each specimen (excluding salmonid eggs) to a foraging
guild based on the primary foraging mode of the species within that taxon, after Cummins
(1973), and into one of seven size classes, based on 5 mm increments. 1 used the product
of frequency and size class as an index of total prey biornass. This prey biornass index
(PM) is a comparative estimate of the total prey available for harlequin ducks, and avoids
time consum ing methods such as measuring dry weights.
Harlequin duck surveys
Slandcrd Dala
For ail harlequin duck surveys we recorded the observer(s), date, start and finish
times, locations, and elevations (m), cloud cover, estirnated wind speed, and precipitation.
For each sighting we recorded: time, location, elevation, species, number of males,
females, young-of-year, unidentified species, total number, behaviour when first
observed, and comments. We also recorded observations of the following potential
predator or competitor species: osprey (Panciion haliaetus), bald eagle (Haliaetus
feucocephaltrs), bel ted kingfisher (Megaceryle alcyon), Arnerican di p per (Cinclus
mexkamis), and any other waterfowl (Anatidae). Following harlequin duck banding
efforts in 1 994, we recorded band combinations.
Mnlipe Hiwr S~irvey
To monitor harlequin duck abundance on the middle Maligne River and lower
Maligne River, 1 established a weekly, rnorning (0800 - 1 130 h) survey of 37 riparian
sites dong the Maligne Lake Road (Table 2.1, Fig. 2.2).
Observers drove the Maligne Lake Road frorn the confluence with the Athabasca
to the M L 0 and stopped at each site to view the stretch of river using 8 x 42 binoculars.
If birds were too far away to determine the species, sex, or age, we used a 45 power
Table 2.1 - Distribution and rafting status of sunrey sites established along the Maligne Lake Road in
Jasper Nationai Park for the Maligne River survey, 1993 - 1995.
SECTION RAFTS NUM33ER PRESENT OF SITES
Lower Maligne River
Medicine Lake
Middle Maligne River (below Big Bend)
Middle Maligne River (above Big Bend)
Eveiyn Creek (tributary)
Maligne Lake outlet
None 13
None 11
None 3
YES* 6
None 3
YES* 1
Note - in 1993 - 1995 rafting was not oermitted from 01 May to 30 June.
Figure 2.2 - Map of the Maligne Valley study area, Jasper National Park, showing the survey sites used in the Maligne River Survey and the area covered by the Maligne Lake survey (1 cm = 3.8 km).
spotting scope. Researchers also recorded when wind or precipitation resulted in poor
visibility conditions, as this was especially critical at Medicine Lake. 1 Iater grouped
these results into three areas frequented by harlequin ducks: lower Maligne River (sites
4- 14) Medicine Lake (sites 15-25}, and ML0
Moiigr~e Lokr Szrtvey
We used a motorboat to conduct weekly, rnorning surveys of the perimeter of
Maligne Lake while travelling at 5 to 10 kmlh, 10 to 50 m from shore. We initiated these
suweys following ice-out and concluded them in late August or early September. Initially
(25 May to 26 June, 1993) we surveyed only the north basin of Maligne Lake and
recorded observation locations using marked zones established in 1992 (Hunt 1993).
After 26 July 1993 we obtained the use of a global positioning system (GPS) instrument
and could accurately record the location of sightings along the entire lake perimeter. We
recorded UTM positions directly from the GPS and tested the accuracy by recording our
location at several known points during each survey. Surveys took approxirnately 4 h to
cornplete, with'a crew of three (one driverlobserver, one observer, and an
observerhecordedGPS operator).
Valley Srrrvey
1 combined the results of the Maligne Lake Survey and the Maligne River Survey
to estimate changes in harlequin duck abundance throughout the rniddle and lower
Maligne River sections. Although the Maligne River Survey only sarnpled a small
portion of the available habitat, while the Maligne Lake survey was continuous, we
conducted these two surveys simultaneously to obtain a consistent estimate of the relative
distribution and abundance of harlequin ducks throughout the middle and lower Maligne
Valley. 1 used the log likelihood ratio (G-test) to compare the weekly frequency
distributions of various classes (adult male, adult female, and young-of-year) at four
different areas (lower Maligne, Medicine Lake, Maligne Lake Outlet, and Maligne Lake)
within and between years.
Maligne Lake Ou fief Swvey
Since 1986, V. Schelhas, a resident natural ist, annually recorded the abundance of
male and female harlequin ducks observed along the first 1.5 km section of the MLO, on
10 consistent dates, during May through July. In 1993, Schelhas, G. Ruddy, and 1
cooperated to conduct these surveys following Scheihas's methods as described by Hunt
(1 994). In 1994 and 1995, 1 estimated harlequin duck abundance at the ML0 from Outlet
Scan surveys (see Chapter 3).
Tribi r f ary Sur veys
From mid-June to late August and early September of each year, we conducted
hiking surveys along most of the Maligne River tributaries in search of broods. Areas
searched included: Excelsior Creek, Watchtower Creek, Beaver Creek, Stovepipe Creek,
Jeffery Creek, Evelyn Creek, Trapper Creek, Leah Creek, Sandpiper Creek, Coronet
Creek, Warren Creek, and the upper Maligne River (Fig. 2.3). We also included the
lower Maligne River in these tributary searches as this area is also used for brood rearing
(Hunt 1993). We developed data sheets for each tributary, which included a topographie
map of the area, and recorded standard survey data on these sheets. To conduct these
surveys, two observers ascended a tributary, on foot.
We classified broods ages based on body shape and plumage development (Gollop
and Marshall, 1954), and later estimated their age in days using harlequin-specific data
collected by Wallen (1987). Assuming 28 days incubation, a mean clutch size of 5.7 and
a typical laying interval of two days (Bengtson 1972), 1 estimated hatch-date (catch-date
minus estirnated age), start of incubation (hatch-date minus 28 days incubation) and start
of laying (start of incubation minus 12 days laying) from the estimated age.
Nesf Di.scoverie.s
During tributary surveys, and al1 other hiking surveys, observers conducted ad hoc
nest searches in habitats typical of brood rearing and nesting. In 1995, researchers
Beaver Creek and Jacques Lake
Upper Maligne River
Figure 2.3 - Map of the Maligne Valley study area, Jasper National Park, showing tributaries surveyed for harlequin broods and nests, 1993 - 1995 (1 cm = 3.8 km).
thoroughly searched al1 islands above the Maligne Canyon, on the lower and middle
sections of the Maligne River, for harlequin duck nests. Following the discovery of an
active nest. by V. Schelhas and myself on the lower Maligne River (16 M y , 1994), we set
up a blind and rnonitored the daily behaviours of the incubating hen.
Middfe Ma/ipe River Survey
At weekly intervals throughout the surnmer, four researchers surveyed the entire
middle Maligne River. Two researchers hiked the bottom section from Medicine Lake to
Big Bend (this section receives little recreational paddling) while the other two hiked
from Big Bend to the ML0 (this section receives al1 the commercial rafting and most of
the recreational paddling). We chose researcher pairs and sections randomly. Al1
researchers hiked upstrearn along the east bank, scanning the river, and recorded standard
survey information in a field notebook. Harlequin ducks observed within the ML0 area
were not recorded as part of this survey. In 1994 and 1995, my supervisors advised me to
reduce the frequency of this survey to roughly once per month.
Harlequin duck capture and banding
Capture and kg-bunding
We used two, black, 60' X 1 O', mist nets (4" mesh) from AVINET Inc., in various
ways, to capture harlequin ducks. In 1995, we experimented with the use of decoys in
mist-netting harlequin ducks. We applied a metal US Fish and Wildlife tarsal band and a
unique combination of coloured, plastic, wraparound, tarsal bands (manufactured by Pro-
Touch Engraving, Saskatoon, Saskatchewan). In this report 1 will refer to individual birds
by an identification number, rather than alphanumeric band combinations, to avoid
confusion resulting from re-banding many individuals with faded and worn-out bands..
We recorded the following data: various measurements (wing, total tarsus, tarsal bone,
head, and bill ) after Dzubin and Cooch ( 1 992), weight (pesola scale, to the nearest 5 g),
age (estirnated from plumage) and sex (deterrnined by plumage in adults and cloaca1
examination of young).
RESULTS
Weather
There was less daily precipitation in May, June, and My, 1994 than for these
months in 1993 and 1995 (Fig. 2.4 and 2.5). August 1994 and 1995 were wetter than
August 1993. Monthly mean minimum ternperatures were below 0°C during May, each
year. The mean minimum temperature for August, varied between years, with August
1 995 being colder. May 1 995 also experienced cold minimum ternperatures though data
collected in May and September were incomplete.
Stream fïow, temperature and turbidity
Cornparisons of the timing of spring runoff, at different elevations in the valley,
rnay provide insight into harlequin duck habitat use and reproductive success at various
elevations and sites. Also, historical stream flow data was only available from a low
elevation flow recorder, so I wanted to understand how these data might reflect stream
flow at higher elevations such as the MLO.
1 had historical data on the abundance of harlequin ducks at the ML0 from 1986
to 1992 and also had stream flow data from the 6th Bridge, on the lower Maligne River,
for most of these years. I wanted to look for relationships between stream flow and
harlequin duck abundance at the MLO. 1 found that early in the season (May and June),
there was a significant correlation between discharge recorded at 6th Bridge and that
recorded at Bridge C on the middle Maligne River (n = 112 r2= 0.57, F = 145.6, p c
0.001). However, once Medicine Lake filled each year, discharge at the 6th Bridge
remained relatively constant, around 40 rn '/s, despite fluctuations in discharge at the
MLO. Therefore, the usefulness of the 6th bridge strearn flow recorder, in analysing the
impacts of stream flow on harlequin duck distribution at the MLO, was limited to early
season flow events (Fig. 2.6)
In 1993, spring runoff was synchronous on the middle and lower Maligne River,
and occurred as a single event, with the highest increasing rate of flow in mid-May
(approximately Julian date = 135). Maximum flows at both gauges were lower in 1993
181 21 1 JUtlAN DATE ( J ~ ~ W )
i 81 21 1 JULlAN DATE (Jm 10 A m )
Figure 2.4 - Scasonnl patterns of daily temperature (maximum and minimum) and precipitation
withiri the Maligne Valley study area, Jasper National Park, 1993 (top) to 1995 (bottom).
M A Y
J U L Y
Mifimm Teml>eralue (*Cl t8 Precipitation (mm)
Minimm Temperatue PC) 8 PreCi~itation (mm)
m
Figure 2.5 - Monthly mean (ISE) minimum daily temperature and mean daily precipitation, in the
Maligne Valley, May - August, 1993 - 1995.
M A Y JUNE JULY AUGUST
MAY JUNE JULY AUGUST 1905
50 r O
MAY JUNE JULY AüGUST
Figure 2.6 - Daily rates of discharge (mJ/s), frorn May to August, on the lower Maligne River at 6th
Bridge (O) and on the middle Maligne River at the Maligne Lake outlet (+), within the Maligne
Valley study area, Jasper National Park, 1993 -1995.
than in 1994 and 1995. In 1994, spring runoff occurred as three distinct events. The
lower Maligne River and middle Maligne River were asynchronous; flow increases on the
middle Maligne River occurred about 12 days later than on the lower Maligne River.
Flow rates up to 24 m3/s occurred mid-May, only slightly earlier than in 1993, however
flows near 40 m% did not occur until early June. In 1995, peak flows were synchronous
on the middle Maligne River and lower Maligne River, however spring mnoff occurred
very laie (approx. Mian = 154).
1 also found a significant correlation between flow levels (staff gauge height) on
the middle Maligne River and Evelyn Creek, a typical tributary (n = 233, r2 = 0.45, p <
0,001) (Fig. 2.7). However, the peak flow events on the tributary were often more
volatile; most notably, in mid-lune 1993 (up 27.6 cm in one day) and mid-July 1995 (up
37.8 cm in three days). There were two more gradua1 peaks in early and late June 1994.
Di fferences in stream temperature were significant between the three years, and
over the sprinç season (May to July) (ANOVA p < 0.001) (Fig. 2.8). The rate of increase
in strearn temperature was similar in 1994 and 1995, however, temperature rise in 1995
was delayed more than a month. Temperatures in 1993 were intermediate, and the rate of
increase was slower; temperatures started sirnilar to 1994 and ended sirnilar to 1995.
Stream temperatures declined gradually after July in 1994 and 1995.
At Evelyn Creek and Bridge C on the middle Maligne River, turbidity was closely
linked to stream-fiow and ranked values ranged from zero (clear) to four (muddy)
throughout the season. However at the ML0 turbidity values seldom exceeded two and
were most often zero as the ML0 remained clear despite dramatic changes in stream-
flow.
Maligne Lake Ice-ou t
We recorded ice out dates of 12 May 1994, and 01 June 1995. The ice-out date in
1993 ,as earlier than 28 May, (derived from field notes) but we did not record the exact
date. 1 was unable to find accurate historical ice-out dates for previous years.
Figure 2.7 - Diiily staff gauge reading (flow height, metres) on the middle Maligne River, at the
Maligne Lake oiitlcl and un Evelyn Creek, a tributary, near its confluence with the Maligne River,
within Jasper National IDiirk, 1993 - 1995.
hl- 's
0.0
a - a
d O4 L
f g 92 'n
-
-
-
MAY JUNE JUW
Figure 2.8 - Monthly mean (k SE) stream temperature, from May to July 1993 (shaded), 1994 (solid)
and 1995 (open), measured at the Maligne Lake outlet, Jasper National Park.
Spawning Activity Index
The peak activity dates for rainbow trout spawning for June are: 9 lune 1993, 6
June 1994. and 7 June 1995 (Fig. 2.9). In 1993 much of the spawning activity may have
occurred before June.
Aquatic lnvertebrate Diversity and Relative Abundance
The most cornmon orders of aquatic invertebrates in kick sarnples were true nies
(Diptera), rnayflies (Ephemeroptera), snails (Gastropoda), stoneflies (Plecoptera) and
caddisflies (Trichoptera) (Fig. 2.10). The quantity o f benthic macroinvertebrate prey,
measured as Prey Biomass Index (PBI), potentially available to harlequin ducks at the
MLO, varied significantly between and within the three years studied (Fig. 2.1 1). The
greatest mean biomass of invertebrates per month, recorded by kick sampling, was in
.lune 1993 (230.5 PBIIsarnple) and Iuly 1995 ( 133.4 PBUsarnple). Ail other samples
were less than 100 PB[.
1 found a significant, positive correlation between the mean PB1 and the mean
daily abundance of harlequin ducks at the MLO, during invertebrate sarnpling dates in
May and June 1993 - 1995 (ANOVA, r = 0.84, F = 16.5, n = 8, p = 0.005) (Fig. 2.12).
Multi-plate sampling in 1995 revealed that the ML0 had the highest PB1 of the
three sites sampled, and PB1 declined with distance downstream from the ML0 (Fig.
2.13). In 1995, kick sampling at the ML0 yielded a greater diversity of invertebrate taxa
than we obtained from multi-plate samples at three different sites on the middle Maligne
River, including the ML0 (Table 2.2). Twelve families collected in kick sampling, and
three families collected in multi-plate sampling were unique, but none contributed more
than 30 PB1 in al1 the samples pooled. Of the eleven farnilies common to both
techniques, nine were identifïed as contributing the most to PB1 in the kick samples from
al1 three years (Fig. 7.10). The Perlidae (Stoneflies) and the Rhyacophilidae
(Caddisflies), the two other farnilies, were present in 1993 and 1994 samples, but
contributed less to the PBI, so 1 pooled them in the "other" category.
Figure 2.9 - Diiily abundance of spawning rainbow trout (Ottclrorlryncrts mykiss), observed daily from
Bridge A at tlic Maligne Lake outlet, Jasper National Park, during June 1993 - 1995.
Figure 2.10 - Relative biomass estimates of various invertebrate prey available to harlequin ducks
foraging at the Maligne Lake outlet, 1993 - 1995. The biomass index is the product of the frequency
and size class; sarnples w r e obtained by kick sampling.
mlo 1803 klck
mlo 1994 kick
mlo 1995 klck
Figure 2.1 I - Monthly availability of invertebrate prey for harlequin ducks foraging at the Maligne
Lake outlet, Jasper National Park. Samples were obtained by kick sampling in 1993 (n = IO), 1994 (n
= 2 I), and 1995 (n = 27).
O 50 1 O0 150 200 250
PREY BIOMASS INDEX (dally mean)
Figure 2.12 - The relationship behveen the mean daily abundancc of harlequin ducks and the mcan
p rey 1)iomass index (invertcbratc abundance x size class) at the Maligne Lake outlet, in Jasper
National Park, May and June 1993 to 1995 (p = 0.014). Invertclirate samplcs are the means of 4
siimpling sites pcr day with thrce (poolcd) kick samples collccted at cach site.
MMARl MEDLA
LOCATION
Figure 2.13 - Downstream gradient of the mean prey biomass index (invertebrates) measured at thrce
sites aiung the rniddle Maligne Rivcr, by multi-plate samphg, 1995. Sample locations arc the
Maligne Lake outlet (MLO, n = IO), Bridge C on the middle Maligne River (MMARI, n = 12) and the
upper end of the Medicinc Lakc delta (MEDLA, n = 7). Mcan PB1 I SE.
Table 2.2 - Diversity and relative abundance of potential food items for hariequin ducks, collected
from the Maligne River, Jasper National Park, 1995, using two different sampling techniques; kick
sampling and bIock sarnpling (multi-plate sarnpler). Croups marked with an X are common to both
sampIing techniques. The biomass index i s the product of frequency and size class.
Simuiifdae Ch&oriom#ae
L m - E m e m d a e Pedodiidae Perldae Rflyzaphilidae AMelida îïpulidae wpm- Hinidinea Siphlonuriâae Pdycentropodiiae Bae tidae Hy droptilidae LeuGtndae Lymne phiiidae Philopotamidae Brachyœnbidae Lep tophlebiidae Palecypoda
nofa - Foraging Gui& are: Shreddars (S), Caaedors (C), Grazers or Scrapers (G), Predators (P) and Omrihror~(~~ (O; aiaer (1 873).
Harlequin duck suweys
Mc~Iigt~e V d k y Sïrrvey
Males and fernales arrived in early May. Al1 males depaned by the third week of
M y . We seldom observed females in July, and in August they were much less abundant
in the valley ihan in May and June. It appears that most non-breeding hens left the
breeding ranges by August. In September, we often observed broods on Medicine Lake.
Many unclassified harlequin ducks in the faIl of 1994 were broods as we were unable to
differentiate hens and young on these dates.
These surveys provided the most consistent, quantitative estimate of harlequin
duck abundance within the Maligne Valley. However abundance of harlequin ducks at
the ML0 is under-represented as only birds visible from the bridge are counted. The
abundance of harlequin ducks throughout the Maligne Valley varied significantly between
years (G = 4 196, p < 0.001) and for the same week of different years (G = 3750, p <
0.001); with the highest count for the entire valley occurring in June 1995 (38 adult
harlequin ducks) (Fig. 2.14). It appears that the breeding phenology of harlequin ducks
occurred later each year, from 1993 to 1995 (Fig 2.15).
Two to three pairs of harlequin ducks occupied sections of the lower Maligne
River throughout the three years and in 1994 several broods used this area (Fig. 2.16).
We obsewed harlequin ducks only twice on the middle Maligne River, during this survey.
These were groups of six and four in the second week of May and the last week of lune,
respectively, 1995, three years after establishing the river closure. The most densely
populated areas were the Medicine Lake delta, the ML0 and, in 1994 and 1995, the
shores of Maligne Lake. Roughly 15 - 25 harlequin ducks used Medicine Lake and an
additional 10 - 25 alternated between Maligne Lake and the MLO. This results in a total
valley count of 27 - 53 individuals, though the maximum valley count was 38 adult
harlequin ducks. The maximum counts of breeding pairs for the total valley survey
resulted in male : female counts of 15: 14 (1993), 19: 1 1 (1994), and 24: 18 (1995). The
maximum count of breeding adults each year, 1993 to 1995 respectively, were: Lower
O Maligne Lake C1 Maligne Lake Oulbl Q Middle Maligne River
Medcim Lake Ei Lower Maligre River
WEEKS (May Io WSepternberI
El Maligne Lake U Maligne Lake Outiel J RI Middle Maligne Rwer B MedWne Lake
Lower Mngw River
Ili) Maligne Lake U MzliQne Lake Outlet I3 Middle Maligne River
Medicine Lake L3 Lower Malige River
WEEKS (May ta mid-September)
1994
Figure 2.14 - Seasonal changes in the distribution and abundance of harlequin ducks within the
Maligne Valley, Jasper National Park, observed during weekly surveys of 37 sites along the lower and
middle Maligne River and a survey of the perimeter of Maligne Lake from May to mid-September,
1993- 1995.
Figure 2.15 - Abundancc of various classes of harlequin ducks within the Maligne Valley, Jasper
National Park, from May to mid-September, 1993-1995. Results from weekly surveys of 37 sites
along the lower and middle Maligne River and a survey of the perimeter of Maligne Lake. The graph
showing "al1 harlequin diicks" includes observations o f 18 unclassified harlequin ducks, observed on
Medicine Lake, 1994, weeks 17 and 18, respectively.
Figure 2.16 - Seasonal clianges in the abundance of harlequin ducks at four areas within the Maligne
Valley, Jasper National Park, observed during weekly surveys of 37 sites along the lower Maligne
River aiid a stirvey of tlic perimeter of Maligne Lake from May to mid-September, 1993 - 1995.
Maligne 1, 2, 2; Medicine Lake 17, 17, 23; Middle Maligne River O, 0, 6; ML0 8, 8, 7;
and Maligne Lake 3, 14, 23. Maximum counts of yo~ng-of-year, during this survey were
4, 18 and 2. in 1993 - 1995 respectively, however some of the 20 birds sighted in 1994
were probably adult hens accompanying the broods.
When pre-nesting harlequin ducks were present in the Maligne Lake area, the
abundance of harlequin ducks at the ML0 was negatively related to that of Maligne Lake,
although this relationship was not significant (p = 0.11 1). In 1993 harlequin ducks
primarily used the MLO, whereas in 1995 harlequin ducks were overall more abundant
but were rnost often found on Maligne Lake (Fig. 2.17).
Maligne Luke O d e f Survey
From 1993 to 1995, the mean annual abundance of male and fernale harlequin
ducks in May and June declined, while the mean annual abundance of males in July
increased; fernales were seldom present in July. In ail three years, the abundance of
females declined dramatically after O 1 July, despite delayed arriva1 of females in 1994
and reduced abundance in 1995 (Fig. 2.18). The long term trend (1986 - 1995) shows a
fluctuating pattern and the mean annual abundance of males and females is higher in 1993
to 1995 ihan the four years before establishing the May and June river closure (Fig.
2.19). However changes in abundance during May (1986 to 1995) carried over into June
and July each year, and the declining abundance in June from 1993 to 1995 occurred in
the absence of commercial rafting.
7i.ibilfnry Swveys
In 1993, 1994 and 1995 we completed 20,25 and 20 surveys of 9, 1 1 and 10
different tributaries (including the lower Maligne River), respectively, for a total of 65
surveys. The lower Maligne River, Watchtower Creek, Beaver Creek / Jacques Lake,
upper Maligne River, and Warren Creek were surveyed every year, and over the three
years we surveyed 15 different tributaries during the brood-rearing season.
We tound broods only on the lower Maligne River, Evelyn Creek, and the upper
Figure 2.17 - The abundance of harlequin ducks observed at the Maligne Lake outlet and Maligne
Lake, Jasper National Park, each rveek, from May to July 1993 - 1995.
M A Y J U N E J U L Y
12 1 15 1 181 21 1
M A Y J U N E J U L Y
Figure 2.18 - Daily mean abundance of al1 (+) and female (O) harlequin dueks at the Maligne Lake
outlet, Jasper National Park, from M a y to Ju1y 1993 - 1995.
M A Y
J U L Y
Y E A A
Figure 2.I9 - Abundance of harlequin duck at the Maligne Lake outlet, Jasper National Park, during
May. June and July, 1986 to 1995, Values before 1993 are means of several surveys per month;
others are mem af several surveys per day.
Maligne River, and observed and banded additional broods on Medicine and Maligne
Lakes. Frequent observations of breeding pairs, and in 1994 a brood, at the outlet of
Warren Creek suggest that harlequin ducks were nesting on this tributary also. In 1992, a
brood was observed on Watchtower creek, a tributary that flows into Medicine Lake
(Hunt 1994). In 1994 the lower Maligne River was very productive (3 - 4 broods), but in
1995 we found no broods on this section during four different surveys. The upper
Maligne River yielded a minimum of 1, 3, and 3 broods in 1993 to 1995, respectively.
On 30 August 1995, while hiking Evelyn Creek, we discovered a nest site (see
below) and captured a brood, including the hen whom we had banded on Medicine Lake,
on O3 June 94, and recaptured at Medicine Lake on 16 May 95 (see below).
N w Discoveries
The third nest recorded in Alberta was discovered in 1993, in the Elbow District
of Kananaskis Country. The sighting was documented by Park Ranger Ken MacKay who
initiated harlequin duck surveys in cooperation with this study. This nest was also a
ground nest on a small island. After examining egg shell fragments and photographs of
the nest site, I am certain this nest was preyed upon, as several shells appeared punctured,
the egg membranes were absent, and several shells were found 2 - 3 m from the nest.
In 1994, local naturalist V. Schelhas located a nesting harlequin duck on the lower
Maligne River in Jasper National Park. Upon closer inspection of the area (16 July 1994),
we discovered the nest, on the ground at the base of a large willow (Salix spp.), on a srna11
island. The hen did not flush when we approached the nest, presumably relying on her
crypsis. This observation represents the fourth documented harlequin duck nest in Alberta
and the second within the Maligne Valley.
Observations of this nest, made from a blind approximately 10 m away, revealed
the following diurnal behaviours. The hen incubated continuously during al1 daylight
h o m , and only left the nest for one hour every evening (- 1900 h). If at a11 disturbed, as
the first day when we set up the blind she did not leave the nest. Before leaving, the hen
covered the e g s with down and quickly left the imrnediate area to feed and preen nearby.
Occasionally she was joined by another female, whom we also captured and banded
(#23). This second hen was active throughout the day and did not appear to be breeding.
The incubating hen was extremely wary when she returned to the nest, and when she
finally entered the nest she hopped in quickly and remained motionless for several
minutes before adjusting into a brooding position. We examined the nest during one of
her feeding absences and counted six eggs covered with a moderate arnount of grey down.
Sometime between 20 - 22 July the young hatched and the hen and brood abandoned the
nesting area. On 23 and 25 July, we observed a hen with six young upstream of the nest
site. Large canyons upstream and downstream of the nest site should have limited the
brood's mobility, yet subsequent surveys yielded nothing. On 3 1 August 1994, we
captured and banded two adult females (# 44 and #5 1) with 6 young-of-year (YOY)
(stage 3), at Medicine Lake. One YOY male had a porcupine qui11 imbedded in his breast,
suggesting an overland journey. Female #44 was resighted at Watchtower Creek on 17
July 1995 and again at Medicine Lake on 04 August 1995 with females #23, #25
(captured on Excelsior Creek, 24 July 1994, with #24 and a third unbanded female) and
three other adult females (one of these may have been #5 1 although we never confirmed a
resighting after capturing her with the brood of six on Medicine Lake). Females #5 1, #23,
#25 and #44 may al1 associate with each other and #5 1 may have been the female we
observed nesting on the lower Maligne River who produced a brood of 6 YOY.
In 1995, I discovered two abandoned harlequin duck nests in Jasper National Park;
one on the middle Maligne River, the other on Evelyn Creek. Both were ground nests on
small islands, and less than 1 m from the watercourse. Like the active nest described
above these nests consisted of a shallow scraping in the clay, lined with a thin (0.5 - 1 cm)
layer of needles and a rnodest amount of grey down. These inactive nests are the fifth and
sixth harlequin duck nests recorded in Alberta. 1 collected the feather and shell remains
from nests #4 to #6 and have several egg shells from nest #3.
1 discovered nest #5 on the middle Maligne River, 10 May 1995, downstream of
the section used for commercial rafting (elevation = 1540 m). The nest was less than I m
from water and at the base of a bent-over willow bush. The nest appeared quite old as the
egg shell frasments were very small and there was no down left. Shell fragments were
too old to determine if the young had hatched successfully or been depredated. 1 think
this nest was probably used in 1993, as we recorded a pair of harlequin ducks near this
site on 0 1 June 1993 and a ben on 09 June, 14 July, and 2 1 July (see results of mid-
Maligne survey).
1 found nest #6 on Evelyn Creek, 30 August 1995, in an alpine area (elevation =
1920 m), under a thickly branching spruce tree. This nest appeared very new, with large
shell fragments, with membranes, and a sirnilar amount of down as the active nest we
found in 1994. The nest did not appear depredated and from the remaining fragments, I
estimated a minimum ciutch size of 5. As mentioned, we captured a brood (3 YOY, 2C
stage), just 1.2 km upstream of the nest, that same day.
Middlr Malipre River Survey
We seldom observed harlequin ducks on the middle Maligne River. In 1993 we
completed 13 surveys of the rniddle Maligne River, between May and August, and
observed harlequin ducks on only four dates: 01 June, a pair feeding at Big Bend (just
downstream of the rafting egress), 09 June, a female feeding at Big Bend, 14 July, a
female in flight at Bridge B (10:34) and a female in flight further downstream at Big Bend
(1 1 :34), (in both cases the female was followed by rafts and was likely the sarne
individual repeatedly flushed downstream through the entire rafting section), and finally
2 1 July a female loafing at Big Bend.
In 1994 we corn pleted two middle Maligne River surveys, 0 1 June and 06 Jul y,
but did not observe any harlequin ducks outside the ML0 area.
In 1995 we completed three middle Maligne River surveys. On 18 May we
observed 13 harlequin ducks, (3 pairs and 1 male near the Medicine Lake delta, and 3
pairs spread over the lower half of the middle Maligne River, downstrearn of the rafting
section). This was very atypical and coincided with a very late ice-out on Maligne Lake
(01 June 1995) and low Rows in the middle Maligne River. On 13 June, we observed a
pair loafing at Big Bend (09:20), and a pair flying downstream, 2 km upstream of
Medicine Lake (09:45). On 17 August we did not observe any harlequin ducks.
Harlequin duck capture and banding
In 1994 and 1995 we banded 100 harlequin ducks in the Maligne Valley, o f which
59 were adults and 4 1 were young of the year (Table. 2.3). Sex ratios within adult and
young of year classes varied only slightly from a 5050 ratio in each year. We captured
1 13 harlequin ducks during these two sumrners and had one fatality (< 1% capture
rnortality) which was a young of year male ( #113), from a brood of five, who drowned in
a mist net on the upper Maligne River.
We recaptured 13 previously banded birds (1 female in 1994, 5 males and 7
females in 1995); rnost of these occurred while banding broods or during passive netting,
as we generally avoided targeting banded birds during active netting. Of these recaptures,
two adults were first banded at Homby Island, B.C. These were a male with a plain green
darvic band (replaced with P2 white lettering on red, Alberta / Jasper band) and a female
with a 1 A, white lettering on green.
We captured similar numbers of unmarked adults in both years (3 1 in 1994 and 28
in 1995). Capture and banding harlequin ducks in 1994 and 1995 resulted in the
following relevant observations, and 1 summarize them here:
In 1995 we re-sighted 44% of the females (8 of 18) and 7 1% of the males (5 of 7)
banded in the Maligne Valley in 1994.
Harlequin ducks banded in Jasper were re-sighted and recaptured on Hornby
Island (including pairs) and other locations in the Straight of Georgia and as far
south as Washington.
Two young-of-year harlequin ducks, a male and a female, from a brood of five
young. captured 06 September 1995 on the upper Maligne River were recaptured
together at Protection Island, Washington on 09 August 1996 (Shirato pers.
cornm. 1996). Therefore al1 individuals within a brood, regardless of sex, I i kely
migrate to coastal wintering sites together.
Table 2.3 - Nurnl~crs of male, female, adult and young-of-ycar harlequin ducks banded in Jasper
National Park, during 1994 and 1995.
1 AGE Y EAR MALES FEMALES ALL
ADULTS 1994 13 18 3 1
1995 16 12 28
1994 and 1995 29 30 59
YOUNG 1994 15 IO 25
1995 7 9 16
1994 and 1995 22 19 41
A L L TOTAL 5 1 49 100 rlote - also 13 harlequin duck recaptured (1 fimale in 1994, 5 niales and 7jèrnales in 1995)
A young-of-year, male harlequin duck also banded on the upper Maligne River in
Jasper, 24 Auyust 1994, was also recaptured on the Coast of Washington on 26
June 1995 and therefore did not return to any breeding ranges in his first year.
These two upper Maligne River broods, which both generated recaptures
on coastal Washington, were from different hens.
We recaptured several harlequin ducks first banded on Hornby Island and sighted
a fernale harlequin duck originally banded in Washington (observed only once at
the ML0 26 June 1995).
We confirmed two cases of successful breeding attempts by individual females in
both years and a third case of a mature female not breeding in two successive
years.
One case of a male pairing with a different female the year following a successful
breeding season in 1994. His old mate was never resighted and the new fernale
was apparent1 y unsuccessful in 1995.
Harlequin ducks moving up the Maligne Valley, from the Athabasca River, in
early spring were captured flying low over the river, just before dawn
(approximately 0500 h) via passive mist netting.
None of 13 males departing the Maligne Valley &ter staging at the ML0 in July
1995, were captured in a 10 ft high mist net erected 24 Wday on the lower Maligne
River, apparently they did not migrate by flying low along rivers at night.
Measu remen ts
Adult female harlequin ducks were significantly smaller than males for al1
measurements (p c 0.001), though male and female Young, from ages 18 to 39 d differed
significantly only in head length (pc0.05) (Table 2.4).
Harlequin duck researchers have used two different tarsus measurements, Total
tarsus is a body measurement frorn the most media1 condyle of the tarsus where it
articulates with the rnid-toe to the rounded exterior portion of the distal condyles of the
tibia (where this bone is nearly at right angles to the tarsus). Tarsus bone is an
46
Table 2.4 - l'vleasurcmcnt uf 38 adult females, 34 adult moles, 19 young females and 22 young males
(some values of n will be lcvs as some measurerncnt sets of adults were incomplctc), Values are
means, l)rackets are standard deviation, bold icttering indicates a significant difference between
males and fcmalcs of that age class (adult p< 0.001; young p < 0.05). Malcs were captured behvcen 10
May and O8 July, whereiis females were captured betcveen 10 May and 06 Septembcr.
ADULT YOUNGOF-YEAR MEAS UREMENT
Females Males Females Males
Total Tarsus (cm) 3.52
(O. 15)
3.7 1
(O. 1 2)
3.53
(O. 14)
Culmen (cm)
Head (cm)
Left Wing (mm)
2.74
(O. 12)
2.29
(O. 1 O)
2.32
(O. 10)
7.42
(O. 11)
Right Wing (mm)
Mass (g)
Condiiion 44.3
(miss : tarsus residual) (67.8)
approximated bone measurement of the distance from the same starting point to the
approximated end of the tarsometatarsus bone, along the outside edge (Dzubin and Coach
1992). In this study 1 often recorded both measurements to determine a conversion factor.
The correlation between these two measurernents is significant for adult harlequin ducks
of either sex (n = 26, r = 0.86, p < 0.001 ) and I developed the following formula to
convert measurements of total tarsus (Tt) to tarsus bone (Tb) for al1 adult harlequin ducks:
Tb = 0.824 + 0.775 (Tt).
Movements within the Maligne Valley
Several pairs captured or sighted at Pyramid Creek and Sucker Creek at their
confluences with the Athabasca, were later sighted up the Maligne Valley (eg. male #5,
femaIe#7, and male #12). These birds used the confluences as staging and/or foraging
areas before moving up the Maligne Valley. Sucker Creek is invaded each spring by
spawning sucken (Cafasfomus catastomics) and in most years 5 -1 5 harlequins can be
seen in this small drainage (< 80 m) adjacent the Yellowhead Highway, foraging on
sucker roe.
Several fernales captured at Medicine Lake or the ML0 prior to nesting were
relocated on tributaries upstream of these sites during brood rearing. Therefore it appears
that most pairs using club sites nest upstream of the club site. 1 can reconstmct three case
histories:
We first captured harlequin duck # 14 (female XO) at Medicine Lake 03 June 1994,
with harlequin duck # 15 (male HO), and recaptured this pair on 15 May 1995 at Medicine
Lake. We also resighted and recaptured the female later that year (Aug 9 and 30, 1995,
respectively) on Evelyn Creek (upstrearn of Medicine Lake) with 3 YOY (we found the
nest 300 m downstream of the brood).
Female #34 was first captured on the Upper Maligne River on 23 August 1994
with a brood of 4 YOY. The following summer, 18 June 1995, we captured her on
Maligne Lake with male #77 and could feel a developed egg in her abdomen. Therefore a
female that was on Maligne Lake during the pre-nesting period is known to nest upstream
on the upper Maligne River.
On 3 1 August 1994, we captured female #44 on Medicine Lake with female #5 1
and 6 YOY. All 6 YOY may have belonged to #5 1, as mentioned earlier (see results
section "nest discoveries"). In 1995 we observed #44, alone, at Watchtower Creek, a high
alpine tributary to Medicine Lake, thus she likely moved upstream to nest. On 04 August
1995 we observed her, back at Medicine Lake, with 6 other adult fernales, two of which
were banded, (#23 and #25). Incidentally, female #25 was captured and banded high on
Excelsior Creek (the adjacent tributary to Watchtower) on 24 July 1994 with two other
females; based on the fact that they should have been incubating eggs during the midday,
and their low body mass, 1 suspect they were non-breeders or failed nesten. Therefore,
female # 25 did not breed in 1994 nor 1995.
Body Condition of Females
The relationship between male adult body mass and tarsus length was highly
significant (n = 54, p < 0.001,1= 0.50), however for adult females this relationship was
insignificant (n = 37, p = 0.53 1, r2 = 0.01). Adult females were significantly lighter than
adult males (see Table 2.5, mean = 536.6 g, n = 38, and 580.1, n = 34, respectively; t-test,
p < 0.001). The high variation in the relative body m a s of females resulted from
drarnatic seasonal variation in body mass (Fig. 2.20). I used the residuals of the tarsus :
mass regression (ie. mass relative to body size) as an estimate of condition. Females
captured very early in the breeding season had relatively poor body condition (n = 4,
mean = -58.0, 2 1.6 SD). During late May and early June, fernales showing signs of
breeding (eg. brood patch, wide pelvis, or an egg present in abdomen, and a strong pair
bond) had extremely good body condition (n = 10, mean = 64.6, 14.0 SD). Several
females that were active midday when breeding hens would typically be nesting,
(classified as non-breeders) showed low to moderate body condition (n = 4, mean = -40.2,
14.3 SD). Females with broods showed the greatest range in body condition (n = 12,
mean = -25.6, 3 1.7 SD).
121 151 18 1 21 1 241 27 1
M A Y J U N E J U L Y 4 U G SEPT
Figure 2.20 - Body mass of female harlequin ducks during the breeding season (May - September)
1994 and 1995. Dark circles are non-breeding females and open circles are proportionally Iarger for
hens showing signs of breeding. Pre-nesting hens were assigned one increment each for: being
paired, brood patch devcloped, open pelvis, and egg in abdomen; brood rearing hens were ranked by
the size of their brood.
Following individual changes in the body mass of 5 females that were recaptured
over two years. 1994 and 1995, reveals a similar pattern (Fig. 2.2 1). Female # 14 (circles)
captured 16 May 1995 weighed only 485 g yet was recaptured 30 August 1995, with 3
YOY, and weighed 5 15 g. The previous year she weighed 590 g when captured 03 lune,
while paired with her mate. Thus her arriva1 weight was very low, her pre-nesting weight
was much higher (in the previous year) and her brood rearing weight was moderate,
Within the same breeding season, we recorded a 1 10 g (19%) loss in body mass of female
#2 (stars) from 25 May to 19 August, 1994 when she was recaptured with a brood of 3
YOY at the IIC stage. Over the two years, the body mass of female #34 (diarnonds)
differed by 80 g (12.5%) when caphired on 18 June 1995 paired (with egg in abdomen)
and 23 August 1994 (with a brood of 4 YOY at the IIA stage). We captured female #23
(squares), during the incubating period in 1994 (cornpanion to nesting female on lower
Maligne River) and 1995; she did not appear to be breeding during either year (active
midday, no brood patch) and had relatively low body m m . Both years, we captured
female #29 (triangles) at Medicine Lake, during brood rearing (Iate Aug.). In 1994 she
had 4 YOY (stage IIC) and weighed 55 g less than in 1995 when she had only 2 YOY
(stage IIA).
Relation between hatch date and elevation
Estimated annual mean hatch dates were consecutively later each year: 15 July
1993 (n = 4, SD = 5.7), 25 July 1994 ( n = 10, SD = 9.2). and 04 August 1995 (n = 5, SD
= 12.8). These dates are later than many studies, (eg. Cassirer and Groves 1991) but
similar to Wallen (1987) who found that most broods hatched between 20 July and 6
August, in Grand Teton National Park, Wyoming (1 980 - 2 135 rn elevation). Hatch dates
were significantly different between 1993 and 1995 (Tukey test, p = 0.034).
Hatching occurred later at higher elevations (> 1400 m). On average, broods
found above Medicine Lake hatched on 3 1 July, more than a week later than those found
at or below Medicine Lake (mean = 23 M y , t-test weakiy significant, p = 0.08, df = 19).
Using obsewations from 1993 - 1995, 1 found that brood size (ie. young per brood)
May - June Jul y A W Sept
Figure 2.2 1 - Changes and inferred changes in body mass of five individual fernale harlequin ducks,
1994 (open) and 1995 (shaded). Symbols represent individual birds. Light Iines show possible
weight trajectory patterns and dark lines show known changes within a single year. See text for
information on individual birds.
decreased with age of young, presumably due to high duckling mortality (brood size =
6.501 + -0.956 [log age] . r2 = 0.224). Therefore, 1 could not use brood size as an index
of reproductive success as high elevation broods were often captured younger, and with
more young per brood than low elevation broods. In 1995 most broods were found at
high elevations.
Thus 1 use the condition of the young as an index of reproductive success. 1
pooled data for male and female young-of-year harlequin ducki, ranging from 18 to 39
days, as there was no significant different, even when correcthg for age (ANOVA, n =
41,MASS=C+SEX+AGE,r2=0.109 ,sex : F=0.680,p=0.415,age: F=3.830, p =
0.058) (female YOY, inean = 407.8 g, SD = 60.9, n = 19, CV = 14.9%, and male YOY,
mean = 422.0 g, SD = 40.8, n = 22, CV = 9.7%). Both sexes showed only slight
increases in mass during this period (Fig 2.22).
1 expected that broods hatching earlier would grow faster and have greater mass
than broods hatching late (ie. rnass of young should decrease with hatch date). However
there was no significant difference in the mass of young, born before and after the mean
hatch date, despite the biased difference in age at the time of weighing. In fact there was
a positive relationship between estimated hatch date and the mean mass of individual
young, relative to their age (age : mass residuals vs hatch date) (Fig. 2.23). Therefore
young hatching later were heavier, relative to their age (n= 41, r = 0.54, p = 0.00 1). This
relationship was robust even when considering broods as a whole (n = 12, r = 0.75, p =
0.024).
This is supported by the fact that, for a given age, young captured at higher
elevations had a later Iiatch date (n = 19) and greater mass (n = 41, r = 0.48, p = 0.007)
(Fig. 2.24). However most low elevation broods were observed in 1994 and most high
elevation broods were observed in 1995, and there was a significant three-way interaction
between year, hatch-date and elevation (Table 2.5).
Figure 2.22 - Relationsliip between age and mass in male (open circles) and fernale (shaded circles)
young-of-year tiarlequiii ducks captured in the Maligne Valley, Jasper National Park, 1994 and 1995.
Figure 2.23 - Relationship between hatch date (Julian date) and the mass of young-of-year harlequin
ducks, relative to their age, captured in the Maligne Valley, Jasper National Park, during 1994
(shaded circles) and 1995 (open circies). Relative mass values are the residuals of the mass : age
regression.
Figure 2.24 - The relationship between brood clevation and a) utimated hatch date (Julian date)(n =
19) and b) the mass of individual Young, relative to their age (n = 4l)(the latter values arc the
residualu of thc mnss : agc regrcssion) within the Maligne Valley, Jasper National Park, during
suweys in 1993 (soiid circles) and capture and I~anding in 1994 (shaded circles) and 1995 (open
circles).
Tal~le 2.5 Influence of ses, age, hatch date, elcvation and ycar effects on the mass of young of ycar
hariequin ducks (ANOVA, n =: 41,8 =0.447)
Mass of young = C + SEX + AGE + HATCH DATE x ELEVATION x YEAR
1 Variable F P
Sex 3.37 0.074
Age 22.62 <0.001
Hatch date x Year x Elevation 15.41 <O.OO 1
Mean Harlequin Hatch-Date
Peak Tributary Flows
Lower Maligne Flow = 30 c.m.s.
Curn. Flow at M L 0 - 100 c.m.s.
50% Cum. Harlequin Use at ML0
Ice Off Maligne Lake
Stream Temp. - 10C at ML0
Peak P.B.I. at ML0
121 151 181 211 241
MAY JUNE JULY AUG
Figurc 2.25 - A cornparison of the annual timing of cnvironmental variablcs within the Maligne
Vallcy, in Javpcr National Park, 1993 to 1995.
M L 0 Club si te
Plottinj the annual timing of environmental variables at the ML0 suggests NO
groups of related events (Fig. 2.25). The dates of stream temperature reaching 10 O C at
the MLO, ice-out date for Maligne Lake, and the peak abundance of invertebrates at the
ML0 al1 show a sirnilar pattern of occurring earliest in 1994, then 1993 and latest in
1995. However, al1 three measures of discharge (lower Maligne reaching 30m3/s, middle
Maligne cumulative discharge reaching 100 m3/s, and peak flow height on Evelyn Creek),
50% cumulative harlequin duck use at the MLO, and mean hatch date show a related
pattern where events occurred earliest in 1993, later in 1994 and latest in 1995.
There were no significant correlations between the timing of spring ninoff
(dischage at 6th Bridge = 30m3/s) and the arrival tirne, maximum abundance, or timing
of maximum abundance of male, female or al1 harlequin ducks at the b E O each year
durin2 1976, 1 977, and 198% 1995 (arrival defined as earliest Iulian date where more than
two ducks were observed at the MLO) (Figs. 2.26 and 2.27). Arriva1 times of males and
females, for a given year, were often identical as paired birds usually arrived together.
This was probably not a result of infrequent sampling in early years, as this pattern
persisted from 1992 to 1995 when surveys were much more frequent. Comparing years,
arrival times ranged 22 days, from 05 - 27 May. The timing of peak abundance showed
much greater variation for males and females both within and between years. Peak
abundance dates ranged 48 days for males (earliest = 17 May, 1986 to 1990; latest = 04
July 1995) and 37 days for females (earliest = 15 May 1991; latest = 2 1 June 1994). Peak
abundance of harlequin ducks occurred progressively later, relative to spring runoff, each
year from 1986 to 1995 (Figs 2.26, 2.27).
1 found a weak, yet significant, negative relationship between stream discharge at
Bridge C, on the middle Maligne River, and the daily mean abundance of female
harlequin ducks at the ML0 (1993-1995) in May and June (n = 76, r' = 0.06, p = 0.035).
The effect of season (Julian date) and the interaction of discharge and season were not
significant in this ANOVA. These data more closely fit a quadratic function [females = -
Peak Abundance I I I I I 1 1 I Arrival Date
1987 1988 1989 1990 1991 1992 1993 19941995
Year
Figure 2.26 - Timing of arrival and peak abundance of harlequin ducks at the Maligne Lake outlet in
Jasper National Park, relative to the timing of spring runoff, [rom 1987 - 1995. Spring runoff is the
date when thc Ilow rate rcached 30mJ/s on the lower Maligne River, and arrival date was defined as
the first date whcn more tlian two harlequin ducks were present at the outlet.
&, Females f 1 1 I I I I I a Males
Year
Figure 2.27 - Timing of peak abundance of male and fernale harlequin ducks at the Maligne Lake
outlet in Jasper National Park, relative to the timing of spring runoff, from 1987 to 1995. Spring
runoff is the date when the fïow rate reached 30m3/s on the lower Maligne River.
6.54 + 0.740 (discharge) + -0.013 (discharge)'], as females were most abundant when
discharse was between 25 - 30 m%.
The mean discharge at Bridge C, weighted by daily rnean abundance of female
harlequin ducks, was 28.6 m3/s 5.57 SD, over the three years and reached the highest
values in 1993, a year of moderate flows. Mean discharge at Bridge C, weighted by daily
mean abundance of male harlequin ducks, was 3 1.4 m3/s * 6.5 SD, over the three years.
I also used weijhted means to examine discharge preference by male and female
harlequin ducks in May and lune, from 1987 to 1995 (Fig. 2.28). 1 used discharge data
from the 6th Bridge flow recorder, and harlequin duck abundance data from the Schelhas
ML0 surveys ( 1 987 - 1992) and this study (1 993 - 1995). During this 8 yr period there
was no consistent relationship between harlequin duck abundance and mean discharge.
Harlequin ducks did not prefer a particular discharge rate, or a rate relative to the mean
discharge in a given season (range used by harlequin duck, relative to mean discharge =
-1 3.6 to 4 1.3) and al1 harlequin-weighted values fell within one standard deviation of the
mean discharge. Females always preferred discharge levels equal to, or lower, than
males,
Similarly, harlequin ducks showed no preference for a specific Stream temperature
at the ML0 in May and June, as they were most abundant at levels very near the mean
temperature, which varied about 2 O C between years, 1993 to 1995.
As mentioned earlier, crude weekly estimates of invertebrate abundance (from
kick sampling) showed a significant relationship to the mean abundance of harlequin
ducks at the ML0 during the pre-nesting period (May and June) 1993 -1995. Despite the
srnaIl sarnple size, this relationship was significant for both male (p = 0.002. n = 8, r =
0.88, F = 23.1) and fernale (p = 0.038, n = 8, r = 0.69, F = 6.49) harlequin ducks at the
ML0 during this time period. These results were similar, but even more significant, for
whole-summer data (May - Aug, 1993 - 1995).
O discharge females
A males
I I I 1 1 I t I I 1987 1988 1989 1990 1991 1992 1993 1994 1995
Y ear
Figure 2.28 - Discharge rates on the lower Maligne River, during May and June, when male (A) and
female (+) harlequin ducks were most abundant at the Maligne Lake outlet, in Jasper National Park,
relative to the mean discharge rate (Ci). Values are weighted means calculated by summing the
produci of the number of ducks present and the corresponding discharge rate and then dividing by
the total frequency. Errnr bars are the standard deviation of the mean discharge rate.
Breeding Phenology and tributary flow
1 found a strong, yet insignificant, correlation between the peak flow height of
Evelyn Creek and the annual mean hatch-date from 1993 - 1995 (Pearson Correlation =
0.98, p = 0.13, n = 3). Mean hatch-dates occurred 46,48 and 41 (rnean = 45 * 3.6 SD)
dayç after peak tributary flows in 1993 - 1995, respectively. This suggests that hens
began laying shortly after peak tributary flows, (10 - 12 days laying + 28 days incubation
= 38 - 40 days from the start of laying to hatch-date).
DISCUSSION
Harlequin ducks arrive in Jasper in early May, from coastal wintering sites in
British Columbia and Washington, and are first seen on the Athabasca River. Most years
in May, harlequin ducks gather at nearby Sucker and Pyramid Creeks to feed on abundant
Sucker (Catnstomus spp.) roe. Harlequin ducks then make early morning flights (0500 h)
up the Maligne Valley, perhaps to assess the condition of foraging and breeding areas.
Arriva1 dates at the MLO, from 1986 to 1995 are surprisingly consistent.
Some harlequin ducks establish breeding and nesting territories low in the valley
while others gather at Medicine Lake, the ML0 club site, or in some years, Maligne Lake
and feed until nesting sites on upper tributaries becorne free of snow and ice. Gauthier
(1988) classified harlequin ducks as type III territorialist, in which there is a strongly
defended rnoving territory. 1 would modify this description for low elevation pairs, which
are type III territorialist which occupy a yiven home range. At the ML0 club site
however, harlequin ducks resemble type 11 territorialist which loosely defend a moving
territory. Mate guarding at club sites was most prevalent when hens were feeding and
alrnost absent at rnutual loafing sites. There may be a trade off between establishing a
breeding territory lower in the valley early in the season, or foraging on a rich food
resource at a club site and delaying nesting until high quality habitats become available at
higher elevations. During this study we found a nest at each of three elevation ranges
(lower Maligne River. middle Maligne River and a high elevation tributary). Harlequin
ducks nesting at upper elevations have the advantage of gaining body condition while
foraging at a high quality club site, but they cannot initiate nesting as early as those
nesting on the lower and middle Maligne River. Their young then experience a shorter
growth period prior to migration to coastal wintering areas. In 1995, most successful
broods occurred at higher elevations. Therefore, at least in some years, waiting at a club
site to gain body condition until superior high elevation nest sites are available, may yield
greater productivity than nesting early at a lower elevation.
It has been shown that waterfowl which hatch earlier generally experience greater
fledging success (eg. Cooke et ai. 1984, Dow and Fredga 1984). Delayed breeding at
high elevation sites can only be advantageous if young raised on upper tributaries
experience faster growth rates and fledge in time to migrate to coastal wintering sites. 1
compared the mass of young, corrected for differences in age, at different elevations
within the Maligne Valley and found that late hatching young from high elevation broods
were significantly heavier than those from low elevations. The growth and mass of
ducklings is important to survival as heavier ducklings are less susceptible to some
predators (Lack 1968). generally have greater body reserves to withstand food deprivation
(Haramis et al. 1986), and c m better tolerate weather extremes (Koskimies and Lahti
1964). Thus increased body mass may account for lower mortality in ducklings
(Lokemoen el al. 1990) and well nourished ducklings may attain flight sooner (Oring
1968). In this study the relationship between mas, elevation and hatch date was
confounded by significant year effects, however this observation bears further
investigation by future researchers.
1 do not know whether the increased growth rate of high elevation broods is due to
better foraging habitats on tributaries, or better breeding condition of females who spent
May and June forasinp. Heavier females tend to lay larger clutches (Krapu 198 1,
Cowardin et td. 1985). may lay larger eggs (Eldridge and Krapu 1988) which in turn yield
larger young (Pehrsson 1982) and higher body weights have been associated with greater
survival probabilities (Haramis el ai. 1986, Pollock et al. 1989). Preliminary evidence
from this study (eg. female 14, see fig. 2.21) suggests that harlequin duck hens arrive at
breeding ranges with low body mass. This is supported by data from Banff, Albena
where 16 female harlequin ducks captured in early May had an average body mass ofonly
535 g, which is lighter than eight of ten pre-nesting hens known to have bred in Jasper
(Smith 19%). 1 found that only those hens which gained considerable body mass
attempted to breed in that season (Fig 2.20). Other researchers have demonstrated that
females store fat after arriva1 at the breeding ranges (Ankney et al. 199 1). Arnold and
Rohwer (199 1 ) predicted a decrease in the variance of nutrient reserves ( m m ) after
laying as al1 females reach minimum body mass. In harlequin ducks the greatest variation
in female body m a s occurred prior to laying, and was between breeders and non-breeders
within the population. The greatest variation in body m a s arnong breeding hens occurred
after laying, as only those in excellent condition, prior to laying, attempted to nest (see
Fig. 2.20). Apparently pre-nesting harlequin ducks with moderate body condition cannot
afford to attempt nesting, and instead defer breeding to the next season. Bengtson (1972)
felt that high incidence of non-breeding females was an adaptation for breeding in habitats
with limited food resources. Contrary to Arnold and Rohwer's (199 1) prediction brood
rearing harlequin duck hem do not reach a uniform "minimum body mass". A
cornparison of the body condition ratings (mass: tarsus residual) of breeding harlequin
duck hens revealed that pre-nesting hens (CV = 2 1.7%) showed much less variation in
body condition than post-nesting hens (CV = 123.8%). Excluding two females who were
captured shortly after arriving at the breeding ranges and were extremely light, the
average mass of a breeding hen, prior to nesting, was 592.5 g (k 32.3 SD, n = 8). During
brood rearing these hens lost an average of 1 1.6% (maximum loss was 19%) of their body
mass and weighed an average of 523.8 g (A 39.4 SD, n = 12).
In 1993, pre-nesting harlequin ducks inhabited the ML0 in record numbers.
Female abundance at the ML0 peaked early on 30 May and mean hatch date was very
early at 15 July. This season ended with warm dry weather in August, which should
positively influence brood survival at al1 elevations. Ln 1994 environmental events
occurred slightly later than in 1993, however despite a cold start in May, this was a very
warm and dry sumrner. Fernale abundance at the ML0 peaked later on 22 June and mean
hatch date was intermediate (25 July), most broods were found at low elevations (eg. at or
below Medicine Lake). In 1995 environmentai events occurred much later than other
years. There really was no peak in female abundance at the ML0 (n = 2 on 19 May) as
the club site harlequin ducks fed in other areas, prirnarily the northeast shores of Maligne
Lake. Mean hatch date was much later (04 August), and most broods were found at
higher elevations, above the MLO.
During this study, most broods in the Maligne Valley were found at low
elevations (< 1400 rn ) in 1993 and 1994, and high elevations in 1995. This was
surprising considering the 1995 season was delayed and much wetter than 1994 and
significantly colder in May and August. 1 expected that a shorter brood rearing season
with cold, wet weather in August would negatively influence brood survival, especially at
higher elevations, but the reverse occurred. The fact that high elevation broods were
captured younger and had therefore experienced less mortality cannot explain the annual
variation in the number of broods observed. Bengtson (1972) felt that seasonally low
temperatures or high precipitation levels may alter harlequin duck behaviour and, during
early brood rearing, negatively influence productivity.
Delayed breeding chronology in Grand Teton National Park, relative to Glacier
National Park and Iceland, was attributed to later snow-melt (Wallen 1987). However
Wallen did not comment on whether years with delayed breeding resulted in fewer
broods, especially at higher elevations. Despite the higher latitude, harlequin ducks
breeding in Sawrnill Bay, Alaska, in 1979 and 1980 hatched their young from 3 -1 5 July,
roughly 15 - 20 days earlier than harlequin ducks in this study (Dzinbal, 1982). This
i ndicates that migration distance and nesting elevation (ie. snow melt affecting habitat
availability) may be the rnost important factors affecting hatch date. In both areas, pairs
arrived on the breeding ranges in early May, so the impact of a long migration is not
delayed arrival, but possibly reduced energy reserves upon arrival at the breeding area.
The only strong correlation between harlequin duck behaviour and stream flow
was for mean hatch date and peak flows in tributaries. Cassirer and Groves (1991)
identified discharge as a significant factor affecting the initiation of nesting. 1 suggest
that female harlequin ducks initiate lay ing immediately foliowing peak tributary nows,
thus mean hatch date should occur approximately 38 - 40 days after peak flows (1 O - 12
days laying and 28 days incubation). Fiarlequin ducks may assess spring runoff on the
tributaries directly while scouting for nesting sites, or indirectly by the timing of spring
runoff on the main rivers as there was a reasonable correlation between stream flow on
the tributary and the main river. Initiating nesting immediately after spring ninoff on the
tributaries would reduce the likelihood of nesting sites being flooded out and allow
fernales to nest as close to the stream as possible. Proximity to the strearn likely reduces
the chance of mamrnalian predaton such as mink, (Muslela vision) intersecting the
fernale's scent trail (from her many evening foraging trips) while foraging along the
stream. Al1 three nests located in this study were within 1 m of the stream. In this study
one researcher observed a mink unsuccessfully attack a group of harlequin ducks loafmg
on a srnail grave1 bar twice in one evening.
Stream temperature has been linked to spawning in trout and behaviours of aquatic
invertebrates. The optimum temperature range for growth in stoneflies is 5 - 12 O C
(Jewett 1959). Both trout eggs and aquatic invertebrates are potential prey for harlequin
duck at the MLO, therefore 1 felt that changes in stream temperature may determine
habitat use by harlequin ducks, but 1 found no link between harlequin duck behaviour and
Stream temperature during this study.
Bengtson and Ulfstrand ( 1 97 1) found a strong relationship between benthic
standing crop and breeding frequency in harlequin ducks. Despite the low invertebrate
biomass at the ML0 in 1995, multi-plate sampling along the middle Maligne River
clearly displayed the downstream gradient in invertebrate abundance that makes the ML0
important for harlequin ducks. Exceptionally high invertebrate biornass, especially filter
feeders, within the first few hundred metres of lake outlets has been well docurnented but
remains poorly understood (Richardson and Mackay 1991). This phenornenon is most
likely responsible for the establishment of a harlequin duck club site at the MLO.
I feli that the abundance of harlequin ducks at the ML0 may Vary, seasonally and
annually, with variation in the abundance of benthic rnacroinvertebrate standing crop,
There was evidence of this at the ML0 as the annual abundance of harlequin ducks
declined from 1993 to 1995 as did the estimated biomass of invertebrates. Other studies
have found that srnaller, less nurnerous, avian predators such as Dippers (Cinelus spp.)
can significantly alter the density or availability of benthic macro invertebrates (Harvey
and Marti 1993, Ormerod and Tyler 199 1). Bechara and Moreau (1 992) demonstrated
that selective predation by trout in a Stream reduced the abundance of larger benthic
invertebrates (Mayflies and Caddisflies) allowing smaller invertebrates (Midges) to
increase in abundance due to reduced cornpetition.
The primary prey items for harlequin ducks at the ML0 are likely the stonefly
l arvae ( Pleco p tera) (Families: Chloroperlidae and Perlodidae) as these accounted for
much of the estimated biomass and provide the largest food "package" (1 5 -35 mm) for
foraging harlequin ducks. These stonefly larvae rnay take 1 to 3 or more years to mature
(Jewett 1959, Hynes 1976) therefore growth of this population rnay not be reflected in
invertebrate biomass samples for several years.
Dr. Dave Donald (unpubl. data) identified the complete stonefly fauna found at the
ML0 between May and September from samples collected, on 10 sampling days, from
1976 to 1979. The most abundant species, and the timing of their abundance over these
four years, were as fol lows: Zapada cinlipes, (Nemouridae) f = 2 10 (May and June),
Sivel/scr coolorc~der~sis, (Chloroperlidae) f = 120 (late lune to early Sept. with rnost in
August), Sri~ci/linpaliidufa,(Chl~roperlidae) f = 77 (mid-Aug. to late Sept.), Capnia
co~,frr.scr. (Capniidae) f = 36 (late May to mid-July). Donald's data suggest that
Nemouridae and possibly Capniidae were the main prey of harlequin ducks foraging at
the ML0 in May and June, in the 1970's. However neither of these families were
abundant in 1993 - 1995. Thus there has been a dramatic change in the species
composition of Plecoptera at the MLO. The cause of this change is unknown but rnay
relate to water quality as Nemouridae and Capniidae feed on detritus and algae, whereas
Chloroperlidae and Perlodidae are typically carnivorous (Clifford 199 1. Hynes 1976).
Black fly larvae also accounted for a large portion of the biomass in our samples,
however they were so small(1 mm) that they may not provide an efficient food source for
harlequin ducks. An abundance of blackfly larme on the middle section of the middle
Maligne in July 1995 did not attract any harlequin ducks.
Sampling benthic macro invertebrates in the middle of a raging river,
approximately I - 2 m deep, with a large angular rock substrate proved problematic. Kick
samples provided the best approximation of where harlequin ducks were feeding,
however these data were, at best, comparative. Multi-plate sampling should have been
more quantitative, however sample sizes were small and 1 was concerned that repeated
sampling of the same artificial substrates may lead to an oves representation of colonizer
species and an underestimation of invaders. Furthermore, some species may not inhabit
these artificial substrates. Rabeni and Minshall (1977) found that colonization was
markedly reduced on large substratum sizes (4.5 x 7.0 cm). Species diversity represented
in multi-plate samples was poorer than from kick samples and some foraging guilds were
under-represented. Kick sampling identified genera from dominant foraging guilds as
follows: 1 collector, 1 omnivore, 2 grazerslscrapers, and 4 predators; while multi-plate
sampling identified 1 collector and 3 grazerhcraper genera as the dominant guilds.
Therefore predators, which include both genuses of stonefly larvae, were under
represented in the multi-plate samples as these were likely poorly colonized sites for an
invading predator species.
1 recommend that future researchers consider frequent, timed kick samples, with
five replicates at each site (Platts, Megahan and Minshall 1983, Anderson 1990), over a
randomly chosen area approximateiy 1 m2, and only collect some of these samples for
species identification (excluding specimens smaller than 1- 2 mm); the remainder could
be weiçhed wet in the field and retumed to the stream. This would allow a more precise
estimate of prey biomass available to harlequin ducks. without influencing the prey
resource or requiring excessive effort.
Hiking surveys along the middle Maligne River indicated that this section is
seldom used by harlequin ducks. The discovery of an old nest site in this section proves
there is suitable nesting habitat for harlequin ducks. With the presence of rafting on the
upper portion of the middle Maligne River, 1 expected harlequin ducks to be displaced to
the lower portion. This effect was not observed.
Researchers suggest that harlequin ducks migrate at night while flying low over
the water (eg. Bengtson 1966, Wallen 1987). Successful eariy moming (0500 h) captures
of harlequin duck moving into the Maligne Valley in the spring 1995, and similar success
by other researchers banding on the Bow River in Banff National Park during spring
arriva1 (Goudie and Smith, pers. comm. 1995) gave support to this theory. However a
week long, 24 Md, mist netting attempt to capture 13 males departing the ML0 in July
1995 was unsuccessful, suggesting that these males left the Maligne Valley either over an
alpine pass by linking tributaries, or by flying down the main valley high over the trees. 1
would support the latter theory as one evening, during the egg laying period, 1 observed a
breeding female flying high above the trees, directly from the outlet of the upper Maligne
River to the MLO.
I found that decoy harlequin ducks are extremely helpful in attracting and
distracting harlequin duck (especially males) during mist netting. After initial efforts
using a hand carved wooden drake decoy, we painted several plastic scaup decoys to
resemble male and female harlequin ducks. We placed a single decoy, or a srna11 flock
during lake captures, on the opposite side of the net of the targeted harlequin duck. This
allowed researchers to remain visible, standing shoulder deep in the lake, while holding
up one end of the mist net, without frightening the harlequin ducks.
SUMMARY
The results presented here indicate the following picture for harlequin duck
ecology in the Maligne Valley during the breeding season. A minimum of 30 - 40 adult
harlequin ducks inhabit the Maligne Valley. Pairs arrive together in early May and
establish breeding territories along the lower Maligne River, or gather at Medicine Lake
or the ML0 club site to forage while waiting for high elevation nest sites on tributary
strearns to become free of snow. Due to this clumped distribution of pairs, the usual
comparisons of pairs per km relative to broods per km as an indication of reproductive
success (eg. Cassirer and Groves 1991) is misleading in the Maligne Valley, as nesting
and brood rearing often occur on tributaries far away from the pairs breeding area. Use of
the middle Maligne River, excluding the MLO, by breeding harlequin ducks was
minimal, as indicated by results of hiking surveys (most conducted in 1993, road surveys
and random observations. However in 1993 one pair nested on the middle Maligne River
downstream of the rafting egress at Big Bend. In July, many males used the ML0 as a
staging area prior to migrating back to coastal moulting sites such as Hornby Island, B.C.
A nesting hen incubated for 22 -23 h/d and typically left the nest at around 1900 h
to feed, bath and preen for one hour. All young broods were found on the lower Maligne
River, Evelyn Creek. Watchtower Creek, and the upper Maiigne River. Hens reared
young in slow water areas near the nest site and gradually they worked their way
downstream. In September many older broods, some without hens, gathered to feed at
Medicine Lake prior to migration. Thus it is important that broods moving to Medicine
Lake in August and September are not inhibited by human disturbance or development.
Reproductive success varied between years and eievations. Significantly later
hatch dates in some years did not reduce the robustness of young (indicated by their body
mass) despite differences in age. In sorne years, high elevation broods, which hatched
later, had greater body condition than early hatching broods, when corrected for age. The
fact that late hatching broods were more robust than those hatching early emphasizes the
need to allow pre-nesting hens to forage undisturbed and the importance of alpine
tributaries as brood rearing habitats.
I was not able to identify any environmental factors (eg. Stream flow, peak flow,
temperature, precipitation, arriva1 of harlequin ducks, ice-out, fish abundance etc.) that
would allow a clear cornparison in the phenology of harlequin duck behaviour between
years. However, despi te considerable environmental variation between years, 1993 - 1995, harlequin ducks generally left the ML0 in the first week of July (except 1995 when
many males staged there until midJuly). Female harlequin ducks were most abundant at
the ML0 when discharge was moderate (28.6 m3/s) and mean hatch dates occurred on
average 45 days after peak tributary flows. Tributary flows rnay be a predictor of hatch
date as laying and incubation time is estimated at 39 - 42 days (6 eggs at 2 days per egg =
12 days laying, plus 29 - 30 days incubation starting from the penultimate or final egg
laid).
Invertebrate abundance plays an important role in the distribution and behaviours
of harlequin ducks. Medicine Lake, the ML0 and Maligne Lake attracted the largest
concentrations of pre-nesting harlequin duck pairs. Between years there was much
variation in harlequin duck abundance at the ML0 and Maligne Lake, which seemed to
offer alternate foraging areas for pre-nesting hens. During the pre-nesting foraging
period. breeding harlequin ducks were most abundant at the MLO, when invertebrate
Ievels at the ML0 were high. I found a signifiant positive correlation between the daily
mean invertebrate prey biomass index and daily mean abundance of all, male, and female
pre-nesting harlequin ducks at the MLO. 1 did not measure invertebrate abundance on
Maligne Lake. Clearly there are over-riding seasonal effects on the abundance and
behaviours of both the harlequin ducks and their prey, as harlequin duck behavioun are
ultimately driven by reproductive requirernents. Hem captured very early in the breeding
season were relatively light, yet only heavier pre-nesting hens went on to breed. It appears
that hens arrive at the breeding ranges relatively light and only those which gain
considerable body condition are able to reproduce successfully. This emphasizes the
importance of undisturbed foraging sites for hens prior to nesting. Brood rearing hens
were considerably lighter than pre-nesting hens (up to 19% less).
CHAPTER THREE
BEHAVIOUR OF HARLEQUIN DUCKS AT AN UNDISTURBED CLUB SITE
l-NTRODUCTION
The main objective of this chapter is to describe the behaviour and detail the
habitat use of pre-nesting harlequin ducks at the Maligne Lake outlet (MLO) in Jasper
National Park. The reason for doing so is that concerns about the ecological integrity of
the Maligne Valley for harlequin ducks has focussed on the MLO, due to the
concentration of pre-nesting harlequin ducks and the presence of rafting activities. 1
wanted to determine why harlequin ducks gather at the ML0 in spring. 1s the ML0
primarily a staging area for birds waiting for higher elevation nest sites to becorne free of
snow? Or is it a foraging site where harlequin ducks, especially females, gain body
condition prior to nesting?
Inglis, Lazanis and Torrence (1989) studied the pre-nesting behaviours and tirne
budgets of harlequin ducks in Iceland at the River Laxa club site. These authors felt that
the primary focus of a pre-nesting female harlequin duck is to feed efficiently in order to
produce eggs and to prepare herself for incubation, which she completes unaided.
However their research showed that at the Laxa club site, male and female harlequin
ducks spent only 7% of the day feeding. Bengtson (1972) felt that small mean clutch size,
the early departure of males, and high incidences of non-breeding females were al1
adaptations for breeding in habitats with limited food resources. Inglis el al. (1989)
suggested that high food density and nutritious food selection by females, gained through
prey selection during longer dives (relative to males), accounted for the lack of tirne spent
foraging but their results suggest that club sites are prirnarily a breeding or staging area
where birds gather prior to nesting.
In Cliapter 2. 1 showed that breeding fernales are considerably heavier during the
pre-nesting period, and lose approximately 20 % of this body mass during egg laying,
incubation, and brood rearing. This suggests that in the Maligne Valley, hens arrive at
the breeding area relatively light, and gain considerable body mass prior to Iaying.
1 felt it was critical to document the feeding patterns and habitat use of pre-nesting
harlequin ducks at the ML0 to a) identify daily foraging patterns and preferred foraging
sites within the MLO, and b) establish "undisturbed" baseline data for monitoring the
effectiveness of any future management activities. The data reported in this chapter were
collected in May and June of 1993, 1994 and 1995, when there was no disturbance by
rafts.
METHODS
Study Site
The ML0 is situated at the northwest end of Maligne Lake and at the terminus of
the Maligne Lake road. The adjacent portion of Maligne Lake, called Home Bay,
receives considerable use by nonmotorized watercraft and is the mooring area for several
large diesel tour boats, two Parks Canada jet boats, and numerous rental canoes and row
boats. The area surrounding the ML0 has several trails but was closed to public access
during May and June throughout this study.
As water flows from Maligne Lake into the ML0 it passes a series of buoy
markers delineating the upstrearn end of the May and June river-use closure (Fig. 3.1).
Once the mouth narrows there is a log boom, which waterfowl often use as a loafing site,
and roughly 60 m downstream a large highway bridge spans the river. The 30 m long
section upstream of the bridge is calm and unbroken. Rapids begin immediately
downstream of the bridge below of a row of large boulders placed during the installation
of a sewage line under the river to the sewage lagoon on the south bank of the MLO.
Downstream tiom the bridge the river descends relatively steeply in a series of rapids,
where large mid-stream boulders are abundant. Harlequin ducks gather here during May
Figure 3.1 - Mnp of thc Maligne Lake outlet in Jasper National Park.
and June from the bridge to a point approximately 1.5 km downstream, and this area is
referred to as the ML0 club site.
Orttlet Scat1 Srrveys
To determine spatial and temporal patterns of harlequin ducks abundance and to
identify feeding areas within the MLO, we conducted scan surveys along a 1.5 km section
of the ML0 in 1993, 1994 and 1995. lnglis el al. (1989) used a similar approach to
investigate the time activity budgets of pre-nesting harlequin ducks in Iceland. 1 divided
the ML0 into five zones and developed a map identifying numerous micro-sites to ensure
consistent reporting of locations (Fig. 3.1). At the beginning of each daily session,
observers hiked this 1.5 km section of the ML0 and recorded harlequin duck observations
from various stations along the route. Observers recorded the sex, zone, microsite name
and type, and activity of each harlequin duck seen. Observers conducted these surveys
hourly, between 0600 to 2300 h, for four days each week.
Time Activity Budgets
In 1993 1 used instantaneous focal animal sampling (Martin and Bateson 1993) to
measure the time-activity budgets of harlequin ducks. Focal individuals were chosen
randomly. During outlet scan surveys (see above), observers assigned each harlequin
duck a number and used a random number table to select a focal individual. We located
the randomly selected individuai and began an observation session immediately. If we
could not differentiate this individuaf duck, we randomly selected an individual of the
same sex within the same river zone. Once a session was completed, the researcher
selected a new individual. If the last focal individual was a male, the researcher selected
randomly from available females. If a focal individual was briefly out of view during the
session, the observer recorded OOV (out of view). If the focal individual left the study
area the session ended and the observer recorded OOA (out of area).
We conducted these observations as follows: for a period of 30 min the observer
classified and recorded at 30 s intervals the instantaneous behaviour of the focal
Table 3.1 - Catcgories of 1)ehaviours assigned during instantaneous focal sampling a t 30 second
intervals for 30 minutes at the Maligne Lake outlet in Jasper National Park. Each behaviour was
first grouped into one of the five main categories, then the appropriate sub-category was assigned.
FEEDCNG
Dive
Pause
Break
Dabble
Dabble iip
Other
LOCOMOTION
W alk
Float
swim
Scoot
F ~ Y LOAFKNG
Eddie
Alert
Rest
Steep
Preen
Bath
COURTiNG
Court
Agonistic
oov -
main activitv is f o r a h g
completely submerged
on surface between dives
short rest during feeding circuit, usually in eddie
tèeding without diving, back still exposed
dabble feeding while movùig upstream in feeding circuit
otlier tèedhg behaviours (ski.cn, peering)
main sctivitv is chanpinv nosition in river
waking
moving with the current
moving ups tream or maintaining position in current
fiutter and swim dong surface
fly above water or ground
main activitv is r e s t in~ or comfort movement~
loaf in calm water
head up, neck outstretched, looking around
heüd Iow
head tucked in
featlier maintenance
dip and bath
main activitv is matinp o r mate ~ u a r d i n g
male and fernale bonding (include copulate)
any territorial behaviour between unpaired individuais
hird rnoved so that it was Out Of View of the observer
individual. We classified 19 different behavioun of harlequin ducks, that fell into four
general categories (Table 3.1). Observen first categorized the general behaviour of the
focal individual and then determined which of the sub-categories best fit the behaviour.
In the analysis, sub-categories of Feeding and Locomotion were grouped into "diving"
and "other feedin~" and "flying" and "other locomotion", respectively and "preen" and
"bath" were grouped into "cornfort". 1 analysed these data by summing the frequency of
each behaviour during the 30 min sampling period. 1 also sumrned al1 frequencies within
the four major behaviour categories of feeding, locomotion, loafing and courting. 1
performed likelihood ratio chi-square tests on the summed data for all 30 min sampling
sessions to compare differences in behaviour patterns. I tested pair-wise cornparisons
using a chi-square test. 1 report focal animal results as proportions (the frequency of a
given behaviour divided by the sample size which is 60, for each 30 minute observation
session) and percentages. To assess whether behaviour pattems varied seasonally, I
ordered the data chronologically and partitioned it into 50 th percentiles. This allowed a
cornparison of two, equal effort, sequential behaviour samples.
WSULTS
Ourler Scan Srrrveys
1 analysed scan suwey data for al1 three years (1 993- 1995) and completed a
detailed analysis of habitat use between the five zones of the ML0 for 1993. The annual
abundance of harlequin ducks at the ML0 in May and June declined significantly from
1993 to 1995 (n = 86 scan surveys, r = 0.68, and pc0.001) (see Figs 2.18 and 2.19,
Chapter 2) despite increased abundance of harlequin ducks observed throughout the
Maligne Valley during this tirne period (see Chapter 2, Valley Surveys). The decline in
harlequin ducks from year to year, was significant (Tukey test, p< 0.001).
Harlequin ducks were most abundant at the ML0 in May (females) and June
(males) of 1993, late June of 1994 (both males and females) and early July of 1995
(males).
In 1993, we completed 103 ML0 scan surveys during the river closure between
28 May and 30 June. There was no significant difference in the weekly mean abundance
of harlequin ducks at the ML0 during this period (May and June) (ANOVA, post hoc
Tukey Test, p < 0.00 1 ), but the abundance of females was greatest in mid to late May, and
males peaked in late June. Harlequin duck abundance varied little during the day, from
0600 h to 2200 h. During these 103 scans we observed an average of 12.2 harlequin
ducks, with a male to female ratio of 2 : 1 (8.2 males, 4.0 females).
Harlequin ducks preferred river sections as follows: zone C , B , D , E, and A.
Foraging most often occurred in zone C , slightly more often than expected in zones D
and E, and was never observed in zone A. Loafing most often occurred in zone C, widi a
slight preference for zone B (Table 3.2)
Time Activiy Brrdgets
From 1 I June to 30 June, 1993, we completed 134 focal animal sampling sessions
(67 males, 67 females), at the MLO, comprising 67 hours of observations (Table 3.3).
Females devoted significantly more time to feeding (30% vs 21.6%), than males, and less
time to locomotion (6.9% vs 9.8%), loafing (59.1% vs 65.0%), and alert (2.1% vs 4.7%)
posture. Differences in loafing time resulted from increased alen, comfort rnovements
(preening & bathing), and time spent loafing in eddies by males while fernales fed (ie.
mate guarding). Females spent almost 3% more tirne diving (subcategory of feeding)
than males, however this difference was not significant. Diving accounted for only a third
of al1 feeding behaviours. Other behaviour differences between sexes were not
significant. Both sexes spent almost twice as much time sleeping as they did resting and
very little time was devoted to flying ( <OS%) thus birds generally remained in view of
the observers (<2.5% out-of-view).
The behaviours of females varied little depending on whether they were being
guarded by a male. While mate guarding, males devoted more tirne to feeding and
locomotion. and spent less time loafing than unpaired or solo males (Table 3.4).
Tahlc 3.2 - Distribution of pre-nesting harlequin ducks within the Maligne Lake outlet during May
and Junc, 1993, and the distribution of feeding and loafing activities within the outlet. Zone A is
adj accnt to Maligne Lake and Zone E defines the furthest downstream portion of the Maligne Lake
outlet.
MEAN HARLEQUIN DUCK PRESENCE M ZONE (% of observations)
GROUP ABUNDANCE A B C D E
Males 8.2 1.3 28.2 44.5 15.2 10.7
Females 4 2 .O 22.7 55.5 10.5 9.3
MEAN HARLEQUIN DUCK ACTIVITY iN ZONE (% of observations)
ACTIVITY ABUNDANCE A B C D E
Table 3.3 - Behaviours of harlequin ducks at the Maligne Lake outlet in Jasper National Park in May
and June, 1993. These Iwhaviours were measured using instantaneous focal sampling, at 30 second
intervals, for 30 minutes (n is the number of sampling periods). Vatues are expressed as percentages.
Asterisks indirates a signiticant differcnce behveen males and fernales for that behaviour category.
GENERAL SPECIFIC FEMALES MALES Chi-square
BEHAVIOUR BEHAVIOUR ('W (%) (P o.os= 18-31
DIVE 11.4 8.6 14.37 FEED*
OTHER FEED* 18.6 13.0 37.97
FLY LOCOMOTION*
OTHER LOCO*
LOAF*
ALERT*
EDDIE
REST
SLEEP
COMTORT
COURT 1.7 1.5 0.95
OUT-OF-VIEW 2.3 2.2 0.0 1
Table 3.4 - Variation in gcneral behaviours of male and female harlequin ducks while paired and
unpaircd (solo). Note that these classifications refer to mate guarding activities during the
observation pcriod, and not necessarily the breeding status for the season.
BEKAVIOUR ALL FEMALES MALES
PAIR SOLO ALL PAIR SOLO ALL
FEED 25.7 31.0 29.3 30.3 26.0 17.4 21.1
LOCOMOTION 8.4 6.1 7.3 6.6 12.4 8 -7 10.3
LOAF 61.8 59.2 57.9 58.7 57.9 70.2 61.8
COURT 1.6 1.8 t .5 1.7 2.5 0.7 1.6
OUT-OF-VIEW 2.5 1.9 3.9 2.7 1.2 3 .O 2.5
General behaviours also varied diurnally. Harlequin ducks increased their time spent
foraging and specifically diving, throughout the day with the peak in feeding activity
between 1700 and 2 100 h (Figs. 3.2 and 3.3). Though infrequent, courtship was often
observed from 0500 to 0900 h and was least often during rnidday. (Fig. 3.2) Very little
time was devoted to flight and there was no peak period of this activity (Fig 3.4).
DISCUSSION
Harlequin ducks rnost often fed by diving in fast flowing water and typically
foraged in a circuit pattern. A foraging bout consisted of a series of dives down through a
section of rapids, followed by swimrning upstream along the riverbank, sometimes
dabbling as they went. The dive circuit during a foraging bout often occurred in a
predictable pattern and individual birds could be identified, over a several day period, by
their particular "circuit routiney'. Harlequin ducks probably learned exactly where to dive
in the strong current to gain access to favourite foraging surfaces in the large boulder
substrate. After a 15 to 20 minute foraging bout, harlequin ducks returned to a mid-
stream loafiny site, preened for 5 -10 minutes, then rested or slept for an hour or more
before beginning another feeding bout. During May and June, sleeping behaviour (head
tucked on back) was alrnost twice as common as resting behaviour (head low).
Harlequin ducks preferred to feed and loaf on the sections of river immediately
downstream of the bridge, where the rapids began. Feeding most often occurred in Zone
C, and use of zones B and D only increased as the total nurnber of harlequin ducks at the
ML0 increased. One large cobble island, (Broken Island) on the river left side of zone B
was a favourite loafiny site. Harlequin ducks preferred to loaf on midstream sites (rocks,
logs, or grave1 bars). During May and June, harlequin ducks were seldom observed in the
section upstream of the bridge and were never observed feeding in this calm section
during scan sampling.
Abundance at the club site varied little throughout the day, suggesting that
harlequin ducks foraging at the ML0 did not seek out alternate habitats for loafing or
T l M E O F D A Y
Figure 3.2 Diurnal changes in the behaviours of harlequin ducks at the Maligne Lake outlet, Jasper
National Park, 1993. These are the results of 103 focal animal sessions (30 min. each) conducted
between 28 May and 30 June. To examine for seasonal effects, the data are divided into graphs a)
and b), which are the sequential50 th percentiles of the data. Diurnal groupings are: AM - 0500 - 0900, NOON I = 0900 - 1300, NOON2 = 1300 - 1700, PM 1 = 1700 - 2100, and PM2 = 2 100 - 2300.
T I M E O F D A Y
T I M E O F D A Y
Figure 3.3 Diurnal chaiiges in the proportion of time spent diving by harlequin ducks at the Maligne
Lake outlet, Jasper National Park, 1993. These are the results of 103 focal animal sessions ( 30 min.
each) conducted between 28 May and 30 June. To examine for seasonal effects, the data are divided
into graphs a) and b), wliich are the sequential50 th percentiles of the data. Diurnal groupings are:
A M - OS00 - 0900, NOON I = 0900 - 1300, NOON2 = 1300 - 1700, PMI = 1700 - 2 100, and PM2 = 2 100
- 2300.
T I M E O F D A Y
T J M E O F D A Y
Figure 3.4 Diurnal changes in the proportion of time spent flying by harlequin ducks at the Maligne
Lake outlet, Jiisper National Park, 1993, These are the results of 103 focal animal sessions (30 min.
each) conducted between 28 May and 30 June. To examine for seasonal effects, the data are divided
itito graphs a ) iiiid b), wliich are the sequential30 th percentiles of the data. Diurnal groupings are:
AM - 0500 - 0000, NOON 1 = 0900 - 1300, NOON2 = 1300 - 1700, PMI = 1700 - 2100, and PM2 = 2100
sleeping. Despite this, several banded birds were observed at the ML0 for very short
periods ranging from several hours to several days, suggesting that some harleyin
only move through this club site en route to breeding ranges farther upstream or on the
eastern slopes of the Rocky Mountains.
At the club site, pairs were often indistinguishable on mid-strearn loafing sites, as
males were unusually tolerant of other males while loafing. Most agonistic interactions
were initiated by, and between males, while guarding a foraging fernale. Agonistic
interactions between guarding males and an intruder female where usually initiated by the
paired female (by head-bobbing); othenvise the paired male would often tolerate a second
fernale foraging nearby.
As expected female harlequin ducks devoted considerable time to foraging;
significantly more than males, and approximately 20% more time than observed in
Iceland (Inglis et al. 1991). The lower percentage of time devoted to foraging, by
harlequin ducks in Iceland may result in part from longer daylight and/or greater prey
biornass in Iceland. In Jasper harlequin ducks were only active from 0600 to 2300.
Males often foraged by dabbling while guarding a foraging fernale. Unlike the
observations of Inglis (et al. 1991), the tirne spent diving by females was not significantly
longer than that of males, therefore, in Jasper, there is no evidence to suggest females are
selecting larger or more nutritious prey. Harlequins fed througout the day with foraging
activity reaching a peak in the afternoon (1 700 - 2 100 h). Interestingly, preliminary data
suggests that higher levels of invertebrate drift occur in the afternoon at the ML0
(Vennesland 1996). So harlequin ducks may be intensifying their foraging efforts when
prey are most accessible, or just filling up before nightfall.
As in this study, Dzinbal and Jarvis (1 982) found that paired female harlequin
ducks in Alaska spent much less time feeding (2 1%) than many other species of ducks
and that 53-74% of their time is devoted to loafing and preening. They felt that minimal
energy expenditure may be a strategy to deal with unpredictable periods of stringency in a
storm-prone environment. This explanation does not seem as applicable in Jasper, and it
is unlikely that females harlequin ducks, would profit from precautionary loafing
irnmediately prior to nesting. 1 suggest that the tirne spent preening reflects the
importance of feather maintenance for a duck feeding in such a cold and turbulent
environment, and that loafing is actually time spent metabolizing prey and possibly
recovering energetically, following intensive foraging bouts. Unlike many waterfowl,
harlequin ducks are seldom able to feed at a slow steady Pace as their whitewater foraging
environment demands periods of maximum exertion, through heat loss and aerobic
output, while diving and swimming in an aggressive current. I would expect the patterns
of foraging intensity in harlequin ducks to be more similar to piscivorous species such as
Mergansers & f m p . s spp.), than to many of the dabbling and diving ducks.
In general, these behavioural observation support the idea that the ML0 is a site
of intensive feeding activity, especially for females, in the period prior to nesting.
Foraging occurs throuyhout the day, with peak activity in the afternoon (1 700 - 2 100 h).
Harlequin ducks foraging at the ML0 prefer to feed in the river sections downstream of
the bridge, but above where the sewage lagoon line enters. In the next chapter 1 consider
the behaviour of harlequin ducks at the ML0 club site during July of these years, when
the Maligne River was open to commercial rafting.
CEAPTER FOUR
BEHAVTOUR OF EIARLEQUIN DUCKS AT A DISTURBED
CLUB SITE
INTRODUCTION
Boere (1975) defined disturbance, related to human intrusions, as "any situation in
which a bird behaves differently from its preferred behaviour". Other researchers have
defined disturbance inappropriately: "at some sites human disturbance was alway present
so 1 only recorded when birds flushed" apparently to avoid sampling habituated
individuals (Burger 198 1). In this study, 1 defined disturbance as any hurnan intrusion
which had the potential to disrupt harlequin ducks from their normal behaviours. Within
the confines of the ML0 this definition was easily applied and very unambiguous.
In Jasper National Park, there has been considerable debate as to whether the
presence of commercial whitewater rafting on the middle Maligne River, affects harlequin
ducks foraging at the Maligne Lake outlet (MLO). If so, how does rafting impact the
population of harlequin ducks within the Maligne Valley? There has been considerable
research on the effects of human disturbance on waterfowl. Several reviews address
topics relevant to the confîict between harlequin ducks and commercial rafting at the
Malgine Lake outlet. These include: the effects of nonconsumptive recreation on wildlife
(Boyle and Samson 1985), the effects of recreation on freshwater plants and anirnals
(Liddle and Scorgie 1980) human disturbances of waterfowl (Korschgen and Dahlgren
1992), disturbance to waterfowl on estuaries (Davidson and Rothwell 1993), and
recreational-boating disturbances of natural cornrnunities and wildlife (York 1994). In
most cases researchers have measured the effects of disturbance on waterfowl by
documenting the observable reactions during disturbance events (eg. Kahl 199 1, Burger
198 1, Konchgen et al. 1985) or measuring displacement from preferred habitats (eg. Fox
et al. 1994, Thornburg 1973). Researchers then use optimal foraging theory as a basis to
conclude that increased energy devoted to flight, decreased foraging time and
displacement from preferred foraging sites negatively impacts the energy budget and may
similarly impact the population.
Many researchers have comrnented on the negative impacts of various in-stream
disturbances on harlequin ducks, but most evidence is anecdotal or at best correlational,
and without controls. Diamond and Finnegan (1993) observed that harlequin ducks
normally attempt to escape from boaters by travelling downstream, but boats often catch
up to the displaced ducks and continue to push them downstream. Repeated human
disturbance may discourage harlequin duck nesting and reduce productivity. Harlequin
duck abundance has declined on the Methow River, Washington, which now has "heavy"
levels of recreational rafting (Shirato pers. comm. 1994). The disappearance of harlequin
ducks from the St. loe River, Idaho, corresponded with an increase in recreational usage,
including fishing, floating and swimming (Cassirer and Groves 199 1). Knowles (pers.
comm 1992) reports that, despite the persistence of other waterfowl species, 4-8 pairs of
harlequin ducks no longer inhabit Lake O'Hara, in Yoho National Park. Hunt and
Clarkson (1 993) suggest this extirpation may be due to prolonged and intensive human
use of the area. In Yellowstone National Park visitor use has been restricted at the
LeHardy Rapids, in conjunction with a three year study, in an attempt to restore harlequin
ducks to an historical club site (McEneaney 1994). Most recently, managers in Glacier
National Park, Montana, closed portions of McDonald Creek to al1 fonns of boating
throughout the summer in an effort to protect breeding harlequin ducks (Ashley, pers.
comm. 1995).
Although demonstrating the negative effects of disturbance is a useful first step,
this does not determine the significance of disturbance events (Klein 1993). Not al1
disturbances result in negative impacts. Birds may be able to buffer the impacts of '
disturbance through use of energy reserves, extended time feeding or increasing their
foraging rate. For example waterfowl c m increase their foraging efforts, during non-
disturbance periods to compensate for increased energy demands and reduced foraging
time available (eg. Owen 1972, Goss-Custard and Verboven 1993, Thornburg 1973).
Converseiy, heart rates of Eiders (Somateria spp.) and Oystercatchers ( H a e ~ o p u ~ spp.~
appear to increase considerably when incubating birds are approached by m m or a
helicopter, despite the fact that the birds showed no visible reaction (Gabrielsen 1987,
Huppop and Hagen 1990).
Davidson and Rothwell(1993) emphasize the importance of differentiating
disturbances which results in an effect rather than an impact, both on individuals and on
the population. It is relatively easy to measure the behavioural responses of birds to
disturbance, but it is much more difficult to quantify the effect that these changes in
behaviour have on population dynamics (Cayford 1993). Owen (1993) surnmarized a five
year research project in England as primarily showing how dificult it is to conclusively
demonstrate an impact of disturbance at the population level, or even at individual sites.
Based on reports of refuge managers, Pomerantz (et ai. 1988) developed a classification
scheme in which the effects and impacts of disturbance were ranked into one of the
following categories: a) aberrant behaviour or stress (16%), b) reduced use of preferred
habitat on refuge (14%), c) reduced use of refuge (13%), d) lowered productivity (41%),
e) indirect mortality (5%), and f) direct mortality (12%).
Direct impacts of disturbance, through human intrusion, are usuaily related to
increased mortality due to predation following brood or nest abandonment (Mikola et ai.
1994, Hunt 1972). But at the ML0 the effects of rafts on pre-nesting adults are likely
indirect, such as aberrant behaviour, reduced use of preferred habitat or refuge and
lowered productivity. Ultimately we need to know how the reproductive success of
harlequin ducks breeding in the Maligne Valley will be impacted by the presence of
commercial rafting on the middle Maligne River. Unfortunately reproductive success in
harlequin ducks is difficult to assess directly as breeding densities and reproductive rates
are low and highly variable, and nest sites are difficult to locate. Thus an indirect '
approach is necessary. Belanger and Bedard (1989, 1990) direct observation and time
budgets to examine the energetic costs of human disturbance in geese. They found that
disturbance could affect the geese's activity budgets, distribution, and abilities to store fat
reserves for migration and breeding. Excessive disturbance could also dismpt pair and
farnily bonds and induce mortality. Owen (1993) recommends the use of a behavioural
measure such as feeding rate (which is highly correlated with the dependent measure
being sought), and makes the assumption that a reduction in feeding opportunity might
reduce feeding rates. This would affect body condition and, consequently, survival or
productivi ty.
Davidson and Rothwell(1993) observe that birds are most susceptible to
disturbances when food is scarce or energy demands are high. Bengtson and Ulfstrand
(197 1 ) demonstrated that the breeding frequency of harlequin ducks was food limited. A
comparison of female body mass throughout the breeding season showed that like rnany
other ducks, harlequin duck hem obtained body condition necessary for nesting at the
breeding ranges (see Chapter 2). Therefore both of these conditions clearly apply to pre-
nesting female harlequin ducks.
In this chapter 1 used direct observation of disturbance events to quantify the
frequency and nature of rafting disturbances and estirnate the energetic costs. Secondly 'I
used scan sampling to mess displacement effect. within the MLO. 1 also used time
budgets of pre-nesting harlequin ducks, as an indirect method of measuring the impacts of
rafting on reproductive potential of harlequin ducks in the Maligne Valley. Finally 1 used
"peek" rates to detect changes in vigilance in male harlequin ducks.
METHODS
Parks Canada required that al1 three commercial river users on the Maligne River,
report the following data: date, launch time, and the number of rafts. We used these data
to calculate the frequency, magnitude, and temporal distribution of potential rafting
disturbances to harlequin ducks at the MLO.
In 1993 we used direct observation to record the nature of interactions between
rafts and ducks, and the reactions of the ducks. For each duck-raft encounter observers
recorded the date, time, number of rafts involved, number of ducks of each sex that were
visible to the observer, and their reaction to the rafts: none, alert, swirn, scoot, and flush
(when scooting a bird runs across the surface of the water flapping its wings and then
usually slows to swim away). These reactions are listed in order of their assumed severity.
The reactions of individuals ducks within a flock were not independent, so 1 analysed
reaction data for both individuals and for flocks.
We conducted scan surveys at the ML0 as described in Chapter 3, to determine
the distribution and abundance of harlequin ducks within the ML0 during commercial
river use in July and August. It is important to recognize that comparisons between
behavioural data collected, without rafts in May and June (Chapter 3), are confounded by
seasonal effects, as harlequin ducks progress through the breeding season. The July
opening date was chosen with the intention that most harlequin ducks would have left the
area to begin incubation.
We used instantaneous focal sampling, as described in Chapter 3, to measure the
behaviours of disturbed harlequin duck at the ML0 during the same period.
Peek rates, the frequency or duration of "eyes-open" periods during a given time
of sleeping are used to indicate the degree of vigilance in a group of birds (Lendrem 1983,
1984). 1 predicted that harlequin ducks should be more vigilant when frequently
disturbed by commercial rafting. In 1995, we measured the 'peek' rates of resting male
harlequin ducks four days before and four days after the start of commercial rafting. The
short study period was selected to try to avoid seasonal effects. We conducted these
measurements on males, rather than females, as females were seldom observed at the
ML0 during late June of 1995. We used a stop watch and a spotting scope to record the
number of peeks (eyes open) and the total peek duration (time with eyes open) of sleeping
male harlequin duck for a period of 2 minutes. Birds were chosen randornly. We also
recorded the flock size, loafing site (shore or rock), river zone, time and date.
RESULTS
Commercial River Use on the Maligne River 1986 - 1995.
Annual rafting activity increased rapidly until 199 1 and then levelled at around
1600 rafts per season (Fig. 4.1). The May and June river closure had little impact on the
total number of rafts travelling down the Maligne River each summer. Commercial river
May and June Closure
-,
1986 1987 1988 1989 1990 1991 1992 1993 1994 1995
Ri MAY JUNE JULY 0 AUG SEPT
Figure 4.1 -The total number of commercial whitewater raft trips down the upper-rniddle section of
the Maligne River in Jasper National Park, from May to September, 1986 to 1995. Frorn 1993 to
1995 the middlesection o f the Maligne River was closed to ail human use during May and Junc.
users had never operated on the Maligne River in May, so the two month closure reduced
their operating period by one month. Parks Canada did not prohibit commercial users
from extending their operating season, thus the duration of the rafting season was limited
only by low water levels in August or September. Before 1993, commercial rafting never
continued into Septeniber.
Launch tirnes can tremendously impact the number of disturbance events
experienced by harlequin ducks at the MLO. Three different companies operating on the
Maligne River each schedule either two or three raft trips per day, with maximums of up
to six rafts per trip, depending on the Company. This results in a maximum of 8 different
launch times and up to 3 1 rafts per day. Currently the three companies launch at relatively
consistent times, however these times are staggered to avoid crowding conflicts between
companies. For example, in 1994, the three companies scheduled six different launch
times per day resultinç in disturbances, roughty every hour, from 0900 h to 1630 h.
Duck - Raft Interactions
From 0 1 - 22 My, 1993, we observed 86 separate hariequin duck - watercraft
interactions at the ML0 (Table 4.1). Of these, 85 involved males and 35 involved
females. Commercial raft fleets accounted for 90% of the in-stream disturbance stimuli;
the remainder were recreational kayakers. In total we recorded 213 reactions of male
harlequin ducks and 50 reactions of fernale harlequin ducks for a total sarnple of 263 duck
reactions.
Ninety-three percent of harlequin ducks showed a visible reaction to watercraft
disturbances, and 87% of these reactions involved displacement of ducks, which reacted
to avoid a close encounter with the watercraft. Of the ducks that were displaced by
watercraft, 68% flew, 7% scooted, and 25% swam to avoid rafts. Analysis of flock
reactions. rather than individual responses, results in sirnilar patterns (Table 4.1).
The distribution of reaction types was significantly different for males and
females, with females taking flight more often (Chi-Square = 12.18, p = 0.0 16), however
this difference may be confounded by the fact that al1 but eight of the 35 interactions
Table 4. I - Reactions of groups of 1 -7 harlequin ducks to watercraft disturbances during 86 separate
interactions at the Maligne Lake outlet in Jasper National Park from 01 to 22 July 1993. Total = 263
interactions (2 13 males and 50 fernales).
REACTIONS OF HARLEQUIN DUCKS TO WATERCRAFT
UVDWIDUALS NONE ALERT SWIM SCOOT FLY TOTAL
MALES ( ) 8.45 6.10 22.07 7.04 56.34 1 O0
FEMALES ( ) 0.00 4.00 20.00 2.00 74.00 100
(%) 6.84 5.70 2 1.67 6.08 59.70 100 ALL
CO 18 15 57 16 157 263
FLOCKS fl 9 6 2 1 9 54 99* * note - total > 86, as some tlocks showed mixed reactions.
involving female harlequin ducks occurred within the first 3 days of rafting, whereas 39
of the 85 male interactions with rafts involved unpaired males and were recorded 10 - 22
d after rafting began. Commercial and recreational watercraft affected ducks similarly,
but the sample size for recreational watercraft was too small for valid cornparisons (n =
9).
Once flushed harlequin ducks generally flew downstream several hundred metres,
landed on the river and assumed the "alert" posture. This resulted in repeated flushing
events as the raft fleet moved downstream through the MLO. Typically, harlequin ducks
were ou t-of-view downstream for 5 - 25 minutes, then returned to the ML0 flying
upstream. These birds often ffew past the ML0 to land 200 - 300 m out in Maligne Lake,
where they either loafed on the lake or slowly swam back to the MLO. Later in the
rafting season, male harlequin ducks often flushed upstream, past approaching rafts and
landed near the mouth of the MLO, resulting in minimal dismption to their foraging
efforis.
Outlet Scan Surveys
Each year, from 1993 to 1995, the abundance of harlequin ducks at the ML0
declined shortly after July when the river opened to human use (see Fig. 2.18, Chapter 2).
This departure of harlequin ducks was predicted as hens begin incubation and males
return to coastal moulting areas, however the timing of this departure from the ML0
varied little over the three years despite large variation in the onset of spring and hence in
the breedinj phenology of the harlequin ducks.
From O 1 July to 16 August 1993, we completed 143 scan surveys of the MLO. In
July and August harlequin ducks were much less abundant at the ML0 than in May and
June, though their numbers remained relatively constant throughout the day from 0500 to
2230 hrs. Thus harlequin ducks remaining at the ML0 did not move to alternate habitats
each day during the period of intense human activity.
Detailed analysis of the 1993 data showed significant differences in the mean
weekly abundance of harlequin ducks at the ML0 between: a) the lasi week of May to
the end of June (closure); b) the fint week of July (initial opening); and c) the second
week of July to the third week of August (ANOVA, post hoc Tukey Test, p < 0.00 1).
The distribution of harlequin ducks within the ML0 during 1993 varied
considerably before and after the river closure. In May and lune, harlequin ducks spent
most time in zones C and B. In July, after the river opened, the few remaining harlequin
ducks spent most of their time closer to the mouth of Maligne Lake by using zones as
follows: B, A and C (Fig. 4.2) (G = 339, df = 4, p < 0.001). This trend is strongest in the
distribution of mated pairs of harlequin duck, (Fig. 4.2)(G = 46, df = 4, p < 0.001),
although the sample size for paired harlequin ducks is smaller in July. The distribution of
males (G = 285, dj= 4, p < 0.00 1 ) and females (G = 57, df = 4, p c 0.001) within the
ML0 shifted upstream towards Maligne Lake once rafting began.
There was a significant shift in the distribution of where harlequin ducks were
found loafing (G = 146, df = 4, p < 0.00 1) and feeding (G = 77, df= 3, p < 0.00 1) once
rafting began. We never observe harlequin ducks feeding in zone A during these surveys
(Fig. 4.3).
Time Activity Budgets
Table 4.2 shows the changes in the mean percentage of time harlequin ducks
devoted to various general behaviours, before and after the river opened to human use.
Feeding decreased by 40% while time out-of-view increased threefoId. In June, females
and males spent 2.1% and 4.7% of their time in the "alert" posture, respectively. In July,
once mate guarding decreased and rafting began, females "alert" time increased to 5.3%
and males decreased to 1.9%.
Figure 4.4 shows seasonal changes in specific behaviour categories. The mean
proportion of time spent divin& other feeding, eddied, sleeping, courtship/agonistic, and
in comfort behaviours (ie. preening and bathing) decreased significantly in My, whereas
the mean proportion of time spent flying, other locomotion, resting, and out of view
increased signi ficantl y (Kruskal Wallis, pC0.05).
OPEN
A B C D E zone
CLOSE0 10
A '1 " i OPEN
A B C D E zone
A 8 C D E zone
Figure 4.2 - Changes in spatial distribution of harlequin ducks at the Maligne Lake outlet, Jasper
National Park, rccorded during hiking surveys along the flrst 1.5 km of the outlet area, without
(CLOSED) and with (OPEN) human disturbance from commercial whitewater rafting. Zone A is
adjacent to M:iligne Lake and consecutive zones are downstream. AI1 distribution shifts were
significant (West . p < 0.05).
CL08ED OPEN
A B C O E zone
FEEDINQ
A B C D E
zone
Figure 4.3 - Changes in distribution o f loefing and foraging harlequin ducks at the Maligne Lake
outlet, Jasper National Piirk, recorded during hiking surveys along the first 1.5 km of the outlet area,
without (CLOSED) and with (OPEN) human disturbance from commercial whitewater rafting. Zone
A is adjacent to Maligne Lake and consecutive zones are downstream. AU distribution shifts were
sigriificant (G-test, p < 0.05).
Table 4.2 Changes in the mean percent of time harlequin ducks devoted to different behaviours with
the Maligne River closed (June) and open (July) to hurnan use in 1993. Results of 277 focal animal
ohyervation scsviuns at thc MLO. 1 recorded behaviours every 30 seconds during each 30 minute
session. Values in brackets are the standard error of the mean.
RIVER CLOSED RIVER OPEN
(JuluE) (JULY)
males females Ail males femaies All BEHAVIOUR
(n = 671 (n = 6n (n = 134) - (n .= 143) - - -
FEEDING 21.6 30.0 25.8 (2.2) 14.8 16.3 15.1 (1.3)
LOCOMOTION 9.8 6.9 8.4 (0.8) 10.1 6.9 9.4 (1.2)
LOAFING 65.4 59.2 62.0 (2.7) 64.9 66.3 65.3 (2.3)
COURTSWIP / 1.5 1.7 1.6 (0.4) O 0.7 0.2 (0.1)
AGONISTIC
OU-r 01; VIEW 2.2 2.3 2.2 (0.7) 10.2 9.9 10.1 (1.7)
DIVE
OTHER FEED
FLY
OTHER LOCO
ALERT
EDDlE
REST
SLEEP
COMFORT
COURTSHIP
OUT OF VIEW
Changes in the diurnal behaviour patterns were consistent with the predicted impacts of
human disturbance. The diurnal distribution of diving behaviours increased during
midday in July (Fig. 4.5) as the proportion of time flying decreased during midday (Fig.
4.6). In the second week of July, harlequin ducks remaining at the ML0 devoted less
time to foraging and more time to flying and were out of view more often during the
midday (Fig 4.7)
Peek Rates ( 1995)
We measured peek rates of male harlequin ducks for 8 d (4 d before and 4 d after)
the onset of commercial rafting. When commercial river use began, male harlequin ducks
were displaced from loafing in zone B to zone A and there was a significant shift in
loafing sites from rock island to shore (Chi Squared = 34, df = 1, p < 0.001) as there was
only one rock island loafing site available in zone A.
During the onset of commercial rafting male harlequin duck Dock size increased
from 2.04 to 6.0 (t-test, t = 3.14, df = 36, p = 0.003). Flock size was significantly
negatively correlated to the total time harlequin duck spent peeking (ANOVA, n = 40, r2 =
0.35, p = 0.001). Date, river closure status, loafing site, time, and the interaction of flock
size and river closure status were not significant in an analysis of variance.
DISCUSSION
Disturbance event observations clearly demonstrate that when pre-nesting
harlequin ducks are approached by fleets of whitewater rafts at the Maligne Lake outlet,
the ducks are most often flushed out of this foraging area. Female harlequin ducks are
more sensitive to this disturbance than males.
Relative to basal metabolic rate (BMR), the energy required for flying in birds is
extremely high, about 12 x BMR (Tucker 1971) and about 2.3 x BMR for swimming and
1.5 BMR for resting (Wooley and Owen 1978). Results of river use data indicate that
T l M E O F D A Y
T i M E O f O A Y
O P E N
T I M E O F O A Y
T I M E O F D A Y
Figure 4.5 - Diurnal changes in the proportion of time spent diving by harlequin ducks a t the Maligne
Lake outlet, Jasper Nationa! Park. These arc the results of 277,3O min. instantaneous focal interval
sessions conducted from I l June to 01 August, 1993. Graphs a) and b) are the sequential50 th
percentilcs of the "river closedndata from June and graphs c) and d) are the sequentialS0 th
percentiles of the "river openWdata from July and August. Diurnal groupings are: AM = O500 - 0900,
NOON I = 0900 - 1300, NOON2 = t 300 - t 700, PM I, = 1700 - 2 100, and PM2 = 2 100 - 2300.
Commercial rafting occiirred during the two noon periods.
C L O S E D
Ir, :- a &'--,",- T l M C O f D A I
OPEN
Figure 4.6 - Diurnal changes in the proportion of time spent flying by harlequin ducks a t the Maligne
Lake outlet, Jasper National Park. These are the results of 277,30 min. instantaneous focal interval
sessions conducted from I l June to 01 August, 1993. Graphs a) and b) are the sequential50 th
percentilcs of the "river closedWdata from June and graphs c) and d) are the sequential50 th
percentiles of the "river openWdata from July and August. Diurnal groupings are: AM = 0500 - 0900,
NOONI = 0900 - 1300, NOON2 = 1300 - 1700, PMI = 1700 - 2100, and PM2 = 2100 - 2300.
Commercial rafting occiirred during the trvo noon periods.
AM Kxl(.11NooirG, PM1
T l M E O F D A Y
AM NOONlKX)N2 PM1 Pb%?
T I M E O F D A Y
AM WW1- PM1 W
T l M E O F O A Y
AM N O O N l ~ PMI PM?
T l M E O F D A Y
Figure 4.7 - Diurnal changes in the behaviours of harlequin ducks at the Maligne Lake outlet, Jasper
National Park. These are the results of 277,3O min. instantaneous focal intewal sessions conducted
from 1 I Junc to 01 August, 1993. Graphs a) and b) are the sequential50 th percentiles of theuriver
closed"diita fiwm June and graphs c) and d) are the sequential50 th percentiles o f the "river
openwdata froiii July and August. Diurnal groupings are: A M = 0500 - 0900, NOONI = 0900 - 1300,
NOON:! = 13011 - 1700, P M 1 = 1700 - 2 100, and PM2 = 2 100 - 2300. Commercial rafting occurred
du ring tlic t w o riooii periods.
even when some cornpanies launched together, which was not always the case, raft fleets
transited the ML0 at least six tirnes per day behveen 0900 - 1630 h. Assuming that 24 %
of harlequin ducks will swim, 63% will take fiight, and 13% show little change (See
Table 4.1, 6 % scooting split between swim and flight responses), on average, energy
expenditure will increase by at least a factor of 8.5 above BMR during disturbances.
This means that if birds were affected for 5, 15, or 25 minutes during each of 6 flushing
events this would result in a minimum of O S , 1.5 and 2.5 h of flushing (flying and
swimming at 8.1 x BMR) per day or 9.7%, 29.1%, or 48.6% increases in BMR above
that of a resting bird. The BMR values used in this estirnate are for normal swimming
and flight and do not account for increased energy due to the "flight response", and
assumes only a restins BMR for birds that became "alert". This estimate also does not
account for enegy lost due to reduced tirne spent foraging due to displacement and
disruption of pair bonds, and increased energy devoted to mate-guarding and agonistic
reactions. Unfortunately we could not assess the duration of disturbances accurately as
most often birds flushed downstrearn, out of view of the observers, however birds often
flew back upstream to Maligne Lake, and these events typically lasted 10 -1 5 minutes. In
many cases birds would not resume feeding at the ML0 for 15 - 45+ minutes.
Once the Maligne River opened to use on 0 1 July, very few female harlequin
ducks were observed at the ML0 and many of these were females returning to the ML0
in the evening to feed; presumably these were incubating hens. This pattern was
consistent for al1 three years, despite dramatic variation in seasonal phenology (see
Chapter 2). Departure of nesting females from the ML0 should have varied with seasonal
phenology. This suggests that the onset of rafting will result in early departure of females
in years when events occur later in the season. Once females initiate nesting, males
appear to gather at the ML0 to forage, in a more relaxed manner, prior to departing the
breeding areas and migrating to the coastal moulting sites. Time budgeting and peek rates
indicate that in My. unpaired male harlequin ducks are less affected by disturbance
(reduced tirne spent "alert" and Iowered peek rates with increased flock size).
Ducks remaining at the MLO, when the river was open to human use, were
displaced to less preferred habitats near the mouth of the river, adjacent to Maligne Lake,
where escape routes are less restricted, but prey availability and mid-stream loafing sites
are poor. Behavioural studies at the ML0 during 1993 when harlequin ducks were very
abundant at this site, indicate that rafting resulted in a significant decrease in time spent
foraging, and an increase in time spent flying. Changes in the time spent foraging may be
due to seasonal effects. On coastal rivers in Alaska, Dzinbal and Jarvis (1982) observed
that fernale harlequin ducks spent less time foraging on drifting salmon roe after rnidJune
when pairs dissolved. The time spent foraging by female harlequin ducks went from 21%
to 15% percent after rnid-June, but remained relatively constant for males (13% to 12%).
Using a sirnilar definition of "foraging", 1 found that at the ML0 foraging went from
30% to 1 6% (females) and 22% to 1 5% (males) after the river opening on 0 1 July 1993.
So although Jasper birds fed more intensively during the pre-nesting period, the similar
dechne in time spent foraging following the courtship period suggests this results from a
seasonal pattern. These data to not reveal the whole picture however, as diurnal patterns
of foraging and flying behaviours at the ML0 changed dramatically following the onset
of commercial rafting. Harlequin ducks showed reduced foraging and increased flying
behaviours during the two midciay periods concurrent with the commercial rafting
activities. By the second week of rafting, the remaining harlequin ducks had increased
the time spent foraging in the morning and evening periods, relative to the first week, but
total foraging time was still significantly reduced. This pattern was exactly opposite of
undisturbed birds in May and June, where foraging was greatest in the afternoon. So
although seasonal effects may contribute to declines in the total time spent foraging after
0 1 July, it is unlikely that seasonal changes in invertebrate behaviour caused the modified
diurnal routine of harlequin ducks foraging at the MLO, where foraging during rafting
activities is reduced.
Little diurnal variation in the abundance of harlequin ducks before and after the
closure. despite the dramatic decline in total abundance, indicates that harlequin ducks are
either tolerant or displaced. Harlequin ducks do not appear to adapt to rafting disturbance
by alternathg between two habitats (eg. foraging at the ML0 morning and evening and
loafing elsewhere during midday rafting disturbances).
Changes in the activity budgets of harlequin ducks were as predicted. Decreased
time devoted to divins and other feeding behaviours, reduced feather maintenance, and
loafing time switching from mostly sleeping to rnostly resting along with increased time
spent flying and alert posture may al1 negatively affect the energy budgets of breeding
waterfowl.
Comparing vigilance in male harlequin ducks before and after the river opening
indicated that, in the period following breeding, staging males were able to compensate
for displacement from preferred loafïng sites, by increasing flock size and therefore
decreasing individual levels of vigilance needed during sleeping periods.
The measurement of peek rate is ambiguous as it does not reflect vigilance unless
peek duration is constant. In loafing harlequin ducks peek duration was not constant.
Figure 4. 8 demonstrates the relationship between peek rate (peeks per minute), duration
(average peek time in seconds) and proportion of tirne vigilant. The maximum peek rate
is only at mean peek duration; and median vigilance (total time with eyes open during
observation period). Therefore the sum of peek duration over a given time period is a
better indication of vigilance.
Roughly ten years before rafting began on the Maligne River, researchers
documented minimum counts of 12 and 6 pre-nesting harlequin ducks at the ML0 in the
spring of 1976 and 1977 (Holroyd, unpubl. data 1976, Holroyd and Karasiuk, 1977).
Historical data since t 986, when rafts were first introduced, indicated that annual
increases in commercial rafting coincided with decreased use of the ML0 by pre-nesting
harlequin ducks (Figs. 2.19 and 4.1). The removal of rafting from the MLO, during June
of 1993 coincided with record abundance and prolonged use by harlequin ducks, however
in the two years that followed, use by harlequin ducks declined (Fig. 2.18). In 1993 - 1995 harlequin ducks either foraged at the ML0 or along the northeast shores of Maligne
Lake. As human disturbance was not a factor in these years, this habitat choice was likely
Figure 4.8 - Pcek rates o f resting male harlequin ducks at the Maligne Lake outlet, Jasper National
Park. Dsta were collected before and after rafting disturbances in June and July, 1995. Peek rate
does not accurately reflcct vigilance as maximum peak rate is achieved at only 50% of maximum
vigilailce.
based on food availability. 1 think the presence of pre-nesting harlequin ducks at the
ML0 depends on the abundance of aquatic macro invertebrate lama (see Fig 2.12) and the
level of in stream human use.
One theory I suggest is that from 1986 to 1992 increasing levels of commercial
rafting displaced harlequin ducks, thus reducing the predation on benthic invertebrate
larvae at the MLO. During this period, the abundance of aquatic macro invertebrate ! m a
at the ML0 may have increased in the absence of this major predator. In 1993, the
removal of rafts coincided with the highest invertebrate abundance recorded in the three
years of this study and also record abundance and prolonged use by harlequin ducks at the
MLO. Intensive predation on benthic invertebrate larvae by harlequin ducks at the ML0
in 1993 may have had a negative impact on the invertebrate populations. It is
questionable whether even 15 - 20 harlequin ducks foraging intensely for 60 days (900 - 1200 duck days) could impact such a large system. In an exclosure experiment, Harvey
and Marti (1993) found that dippers (Cinelus mexicamrs) negatively impacted the
availability of invertebrate prey in small stream sections. Furthemore the most likely
prey for harlequin ducks, the large Plecoptera, may take several years to recover from
heavy predation. Most Perlidae take two or three years to develop and some species of
Perlodidae and Chloroperlidae are definitely semivoltine (Hynes 1976, Jewett 1959).
One complication is that many species of Plecoptera change their habitat as they develop;
most moving shoreward well before emergence, thus there are often seasonal changes in
distribution within the habitat (Harper et al. 1972, Hynes 196 1, Ulfstrand 1967). This
may affect availability for harlequin ducks and will certainly impact their representation
in al1 shore-based sampling techniques.
In any case, the 1993 data demonstrate that in some years, 15 or more pre-nesting
harlequin ducks forage intensely at the ML0 during May and June. Waterfowl are most
susceptible to impacts from disturbances when food is limited or they are facing high
energy demands. Spring is an important time for pre-nesting females, when many will
gain considerable body condition, critical to nesting success. In Chapter 2, 1
demonstrated that upon arriva1 at the breeding ranges in Jasper, fernales harlequin ducks
were relatively light, and only those which gained considerable body mass attempted
nesting. By fall, brood rearing hens had lost considerable body mass (up to 19 %). In this
chapter 1 have shown that most interactions between rafts and ducks result in the du&
being flushed out of the area for some tirne. The frequency and duration of these flushing
events likely increased harlequin ducks energy demands by at least 10% - 29% relative to
that of a resting duck (based on flush times of 5 and 15 minutes). Also the presence of
rafts later in the breeding season coincided with predictable diumal changes in reduced
foraging time and increased flight tirne. Johnson and Sibly (1993) found the breeding
success in Canada Geese (Branla canudemis) was strongly influenced by the reserves
acquired by the female, indicating there was a premium on effective feeding in the pre-
breeding period, prornoted as necessary by protection by her mate.
CHAPTER FIVE
COMMERCIAL RAFTING ON THE MALIGNE RIWR:
EFFECT AND IMPACTS ON HARLEQUIN DUCKS
In this chapter I provide an overview of my main findings in relation to
commercial rafting on the Maligne River. The primary goal of this research was to
develop a better understanding of the breeding ecology of harlequin ducks in the Maligne
Valley of Jasper National Park. This shidy was initiated by concem that the apparent
reduction in the number of harlequin ducks observed at the ML0 from 1986 to 1992 was
due to the onset of commercial rafting in 1986. In this chapter I will review my findings
as they are relevant to the ecological integrity of harlequin ducks and the possible effects
of commercial rafting.
The Maligne Valley provides the breeding habitat for at least 35 - 40 harlequin
ducks. Commercial river use occurs on the upper end of the middle Maligne River from
the Maligne Lake outlet, downstream to an egress point called Big Bend. The lower
portion frorn Big Bend to Medicine Lake provides similar habitat for harlequin ducks, but
is not affected by commercial use, and is rarely paddled.
Results of hiking and road surveys (1993 - 1995) indicated that harlequin ducks
were seldom present on the middle Maligne River. Pre-nesting harlequin ducks may have
been displaced from the upper portion due to the presence of commercial rafting in July,
or historically increasing levels of use throughout the summer from 1986 - 1992. If this
were the case, 1 expected that harlequin ducks would be even more prevalent on the lower
portion as it provides similar habitat for harlequin ducks. This displacement was not
observed. The current distribution of harlequin ducks at the ML0 and on the middle'
Maligne River is predictable given that invertebrate sarnpling indicated an imrnediate
decline in invertebrate abundance downstream of the MLO; a well documented
phenornenon at lake outlets (Richardson and Mackay 1991). However, in 1993 we
recorded four different observations of a pair, downstream of the rafting activities, in the
lower portion of the rniddle Maligne River. The following year 1 found an old harlequin
duck nest at this site in the section between Big Bend and Medicine Lake. This
demonstrated that our surveys were effective in detecting a breeding pair, although no
brood was observed. Egg shell fragments were too deteriorated to determine if the nest
had hatched successfully. The importance of this discovery will undoubtedly generate
much debate, as it provides an argument for eliminating human use from the entire middle
Maligne River during the breeding season. I feel that the detection of one nesting pair, in
this entire section of river, over three years, does not indicate notable use by harlequin
ducks. However, it is possible that the presence of commercial rafting during this study
may have impacted the use of the entire middle Maligne River by harlequin ducks (see
Limitations of Research). Those involved in this debate should consider the difference
between a) effects and b) impacts on individuals and populations. River use on this
section may currently affect the behaviours of one or two pairs of ducks. If river use were
to occur in June and July it would potentially affect pairs and incubating hem. If pairs
were displaced, it would likely be from a marginal foraging area, while high quality club
sites are available nearby (MLOIMaligne Lake and Medicine Lake). Incubating hens are
unlikely to be directly affected as rafting would begin prior to nest site selection, and hem
should then choose nest sites accordingly. However if rafting resulted in hem selecting
nest sites farther from the water, this could increase the probability of predation. Raftiag
activities would not displace nesting hens as it would occur during incubation hours (0900
- 1630) rather than during the hen's foraging break at 1900 h. Some researchers suggest
that during incubation is the least harmful time period for necessary human disturbances
such as road construction (Cassirer pers. comm. 1994). Thus even if pairs are affected, it
is unlikely that this disturbance will impact reproductive success. However, Goudie (et
al. 1994) developed a mode1 which demonstrated that due to the K-selection factors of
harlequin ducks, any additional causes of mortality in excess of even 3% may induce the
decline of a population. Thus if the reproductive success of even one pair was unnaturally
reduced to zero, this could represent more than 3% additive mortality (assuming at least 2
young would have survived 3 years to reproduce) which could impact the local population
of at Ieast 35 - 40 individuals.
During the pre-nesting season, 1 observed up to 18 harlequin ducks foraging at the
ML0 at one time. Band observations indicate that while most breeding pairs show high
philopatry, other birds are transient through the ML0 during this period and likely benefit
from i ts abundant prey . Weights and tirne-budgeting measurements of female harlequin
ducks suggest they arrive at the breeding area light, and only those that gain considerable
body condition go on to nest. Bengtson and Ulfstrand (1971) felt that reduced breeding
frequency in Iceland one year was due to a poor benthic standing crop which affected the
body condition of pre-nesting females. Breeding hens then Iose 10 - 20% of their body
condition during incubation and brood rearing. Most females foraging at the ML0 nested
on alpine sections of tributary streams upstream of the MLO. The tendency to nest
upstream of pair activities was also noted by Benmon (1972). Estimated hatch dates of
these alpine broods were 1 - 2 weeks later than hens nesting lower in the valley. Despite
the later hatch dates, in some years, high elevation young grew faster than young reared
on the lower Maligne River. The greater body mass of high elevation young could result
from better body conditioning of hem prior to nesting, better brood rearing habitats at
alpine tributaries or between year differences in food abundance. Once hem begin
incubating, males gather at the ML0 prier to their migration to coastal moulting sites
such as Hornby Island. After late July, harlequin ducks are seldom observed at the MLO.
Flightless broods, from tributaries upstream of the MLO, were often observed at Medicine
Lake in September, where broods foraged on abundant caddisfly larva prior to their
migration to the Coast. The presence of numerous alpine hatching broods at Medicine
Lake for several weeks each September indicates the importance of maintaining a viable
movement corridor on the rniddle Maligne River in late August and September for '
flightless broods.
The historical abundance of harlequin ducks at the ML0 (19864995) can be
interpreted in various ways. Fluctuating abundance in May, when rafting has never
occurred, indicates annual variation in arriva1 time, or more probably in the prey
availability for foraging harlequin ducks at the MLO. As rafting increased from 1986, the
annual abundance of harlequin ducks dropped. In 1993, when the river was first closed to
human use, record numbers of pre-nesting harlequin ducks were observed at the ML0 for
prolonged periods, but in 1994 and 1995 harlequin ducks preferred to feed on Maligne
Lake. 1 proposed that as harlequin ducks were increasingly displaced from the ML0 prior
to 1993, the abundance of aquatic invertebrates increased. However, in 1993, the high
abundance and long duration of use by harlequin ducks may have depleted this unusually
high abundance of invertebrates. Therefore in 1994 and 1995, invertebrate abundance
was reduced and harlequin ducks fed elsewhere. This theory is supported by the very
high invertebrate abundance at the ML0 in 1993 relative to 1994 and 1995.
Unfortunately, there are no quantitative invertebrate abundance data for the ML0 prior to
1993. Multi-year life cycles in Plecoptera, the most probable prey of harlequin ducks at
the MLO, support the idea that the prey may take more than one season to recover from
intensive predation. Other studies found that smaller, less numerous, avian predators such
as Dippers (Cinclus spp.) can significantly alter the density or availability of benthic
macro invertebrates (Harvey and Marti 1993, Ormerod and Tyler 1991). Bechara and
Moreau (1992) demonstrated that selective predation by trout in a Stream reduced the
abundance of larger benthic invertebrates (Mayflies and Caddisflies) allowhg smaller
invertebrates (Midges) to increase in abundance due to reduced cornpetition.
1 do not believe that commercial rafting is solely raponsible for the displacement
of harlequin ducks from the ML0 from 1986 to 1992. 1 believe that harlequin duck
abundance at the ML0 fluctuates with the availability of benthic macro-invertebrate
larvae such as Plecoptera. Under a regime of repeated in-stream disturbance, foraging
harlequin ducks have two options: iderance (remain at primary site and atiempt to
compensate), or displacement (rnove to another site where there are no disturbances).'
Either option may result in reduced reproductive output if the rate of foraging is
compromised. Therefore the question becomes, which of these two strategies is more
profitable? The answer depends on the level of disturbance at the primary site and the
difference in food availability between the two sites (eg. Prins and Ydenberg 1985).
Factors such as stream flow, temperature, timing of spring run-off and predation likely
combine to affect the availability of this prey (Hynes 1976). However, in years of high
prey abundance, it is essential that pre-nesting harlequin ducks are allowed to feed,
undisturbed at the MLO. Because the Maligne River is narrow and unbraided, any in-
stream disturbance typically results in the displacernent of pre-nesting harlequins,
especially females. This is evident in observations of duck : raft interactions and in the
results of time-budget studies. In-strearn disturbances such as whitewater rafting affected
the diurnal foraging and flight patterns and likely contributed to a reduction in the total
time spent foraging. Impacts such as decreased foraging and increased flight and
vigilance al1 bear an energetic cost on these ducks. It is clear that in some years, the ML0
is an important feeding site for harlequin ducks, at a time when females are gaining body
condition which is likely critical to reproductive success. Fernales arrive at the breeding
ground relatively light, and must gain considerable body condition to nest successfully
and in time for young to fledge. Harlequin ducks nesting in the upper Maligne valley
nested much later than al1 other waterfowl in the Park, and most other populations of
harlequin ducks in North America. Furthemore, young harlequin ducks must be reared
in optimal habitats to complete their growth to migration in such a short brood rearing
period. Al1 of these factors support the concept that pre-nesting foraging by females is
critical to reproductive success and that foraging and downstrearn movements by broods
rnust not be disturbed.
Limitations of Research
Recognizing that my research was limited by the existing pattems of commercial
river use is important. 1 was unable to monitor harlequin duck behaviour at a control site,
as no other lotic concentration is known within Jasper (Clarkson 1992) and only one other
lotic club site has been identified in North America. Concentrations of harlequin ducks at
the Medicine Lake delta, in the Maligne Valley, most often forage in the lake, therefore
feeding behaviours would not be comparable to those observed at the MLO. This research
examines the breeding ecology of harlequin ducks in a watershed heavily influenced by
human use. Furthemore, due to the sensitive political situation regarding the river closure
and pending law suit, Parks Canada was unwilling to manipulate the diumal or annual
timing or intensity of commercial rafting activities. Thus I could not study the impact of
rafting on harlequin duck behaviour, independent of the within year effects of season.
This lack of a control has hvo main impacts: a) Analysis of the effects of rafting
disturbance on the seasonal abundance and behaviours of harlequin duck is confounded
with the breeding phenology as the river closure purposely coincided with changes in
breeding behaviours. In July, as the river opens for human use, male harlequin ducks
rehim to the coast and females initiate nesting. b) Habitats used by nesting and brood
rearing females, and measures of productivity, body condition, and nesting phenology,
may be affected by the presence of intensive river use on the upstream portion of the rnid-
Maligne River, during July through September.
Recommendations
The breeding success of harlequin ducks is intimately tied to stream ecology.
Parks Canada should attempt to minimize human impacts to harlequin ducks when they
are most susceptible. This would include the foraging activities of pre-nesting hem at
club sites and the downstream foraging movements of broods. Considering what has been
learned in this research, 1 suggest Parks Canada consider one of two options:
OPTION A - Eliminate whitewater rafting as a potentiul cause of disfurbance tu al1
hnrlequin ducks in the Maligne Valley.
1. Close the middle Maligne River and the Maligne Lake outlet from
May to September.
This would be the most cautious approach. If this level of
protection is deemed necessary managers should also consider restricting
human activities on Maligne Lake, Medicine Lake, the lower Maligne
River, and all alpine sections of tributaries.
OPTION B: Protect h arlequin ducks /rom disturbance when it is ntd Iikely ?O reduce
productivity. Specificnlly, munage visitor use to allow undisturbed foraging by pre-
nesting females at club sites in the spring and movements and foraging by broodî in
the frrli.
1. Close the Maligne Lake outlet area to al1 users from May to
Septern ber.
This will allow pre-nesting harlequin ducks to forage at the
Maligne Lake outlet club site, undisturbed, in years when the prey
abundance is high. Undoubtedly in some years, these pre-nesting
harlequin ducks will prefer to forage along Maligne Lake, however this
behaviour is currently unpredictable and may fluctuate within a breeding
season.
2. Close the middle Maligne River to al1 in-stream use during August
and September.
To ensure unimpeded movement of broods from nesting areas on
tributaries, downstream through the middle Maligne River to Medicine
lake, this entire section should be closed to al1 in-stream use during August
and September, each year.
These two recommendations may still allow river users to access the Maligne
River, below the ML0 in June and July, during the highest discharge rates. These
recommendations will not protect the few breeding pairs and nesting harlequin ducks that
may wish to occupy areas on the middle Maligne River. If any use downstream of the
ML0 is allowed the users must demonstrate via sound ecological research that their
activities are not affecting or impacting the energy budgets, spatial and temporal
distribution, or reproductive success of harlequin ducks within the Maligne Valley.
Finally, to enhance visitor appreciation and understanding of harlequin ducks and to
reduce the temptation for waterfowl viewers to violate the Maligne Lake outlet closure
area, 1 recommend the following:
3. a) Close the land area adjacent to the Maligne Lake outlet from 01 May
to 30 July each year.
b) Remove al1 stream bank tnils within the Maligne Lake outlet closed
area and rehabilitate the affected areas.
c) Establish a viewing blind on the southwest side of the Maligne Lake
outlet, 100 - 200 m downstream of the bridge, to allow visitors to view
the breeding ecology of harlequin ducks without impacting the birds.
In the absence of in-stream disturbances very few harlequin ducks will be easily
visible from the bridge, as most activity occurs at l e s t 100 m downstrearn. The blind
should be accessed from the sewage lagoon road via a fenced walkway (tunnel style) and
should have g la s windows to minimize noise transmission from visitors. A variety of
interpretive messages could be provided on the back wall of the blind. This would be a
world class viewing opportunity as the Maligne Lake outlet provides a very rare
oppominity to view the lively and often cornical breeding and feeding behaviours of the
world's most interesting waterfowl, the harlequin duck.
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