Changes in the breeding distribution of Buff-breasted Flycatchers in the

southwestern United States: the role of fire suppression. 

Chris Kirkpatrick & Courtney J. Conway

USGS Arizona Cooperative Fish and Wildlife

Research Unit, University of Arizona

Pablo LeautaudPablo Leautaud

Thanks to:

Field Assistants: Dominic LaRoche, Mike Schroff, Eli Rose, Kelly Bergstram, Brian Powell, and Mark Zepp

Logistical Support: Natasha Kline, Don Swann (Saguaro National Park), Josh Taiz (U.S. Forest Service), Bob Peterson (University of Arizona), Shelly Danzer, and Sheridan Stone (U.S. Department of Defense)

Bird Photography: Bruce Taubert and Tom Grey

Empidonax fulvifronsEmpidonax fulvifrons

Arizona New Mexico

from Bowers & Dunning (1994)

from Conway and Kirkpatrick 2007

91% reduction in U.S. breeding range

from Conway and Kirkpatrick 2007

99% reduction in U.S. breeding range

Arizona New Mexico

15% reduction in total breeding range

from Bowers & Dunning (1994)

9 highest sky island mtn rangesWhat is current population trajectory?

• TUCSON

NE

W

ME

XIC

O

MEXICO

AR

IZO

NA

• 71 surveys in Huachucas & Chiricahuas71 surveys in Huachucas & Chiricahuas

• TUCSON

NE

W

ME

XIC

O

MEXICO

AR

IZO

NA

• 44 surveys in 7 adjacent mt. ranges44 surveys in 7 adjacent mt. ranges

• Replicated 1980-83 & 1995-96 surveysReplicated 1980-83 & 1995-96 surveys

• At 200 m intervals along each survey route

• From April to July

• 3-min. passive period

• 3-min. broadcast period

Point-count surveys

• Regress year vs # BBFLs for 23 routesRegress year vs # BBFLs for 23 routes• Test Test HHoo: average slope : average slope 0 0

# B

BF

Ls

Det

ecte

d

bavg = -0.105P = 0.061

• BBFLs have declined on 16 of 23 routesBBFLs have declined on 16 of 23 routes#

BB

FL

s D

etec

ted

bavg = -0.105P = 0.061

• BBFLs have declined on 16 of 23 routesBBFLs have declined on 16 of 23 routes

Carr Canyon

# B

BF

Ls

Det

ecte

d

What’s happened to BBFLs in the U.S.?

Fire suppression implicated…

Coniferous forests in the SW historically subjected to low-severity fires ~1x/decade

From Swetnam and Betancourt 2003From Swetnam and Betancourt 2003

1909

1949

1992

From Covington and Moore 1994From Covington and Moore 1994

Increase in understory fuel loads has contributed to recent increase in frequency

of wildfires in Southwest

from Swetnam and Betancourt 2003from Swetnam and Betancourt 2003

““Recent” FiresRecent” Fires

If observed declines in BBFLs are due to decreased fire frequency, then….

1) Recently burned forests more likely to be colonized by BBFLs

2) Survey points with BBFLs more likely to have evidence of recent fires

3) Survey points with BBFLs more likely to have evidence of more frequent fire events

If observed declines in BBFLs are due to decreased fire frequency, then….

1) Recently burned forests more likely to be colonized by BBFLs

2) Survey points with BBFLs more likely to have evidence of recent fires

3) Survey points with BBFLs more likely to have evidence of more frequent fire events

5 recently burned survey

routes

no no BBFLsBBFLs

detecteddetected

1 pair of1 pair of BBFLsBBFLsdetecteddetected

5 unburned survey routes

Potential Problems:

1) Severity of fires was low2) Sample size of survey routes was small

If observed declines in BBFLs are due to decreased fire frequency, then….

1) Recently burned forests more likely to be colonized by BBFLs

2) Survey points with BBFLs more likely to have evidence of recent fires

3) Survey points with BBFLs more likely to have evidence of more frequent fire events

00 11 22 33 44

0) no evidence of fire1) low-severity surface fire 2) moderate-severity surface fire 3) high-severity surface fire 4) high-severity crown fire

Modified from Ryan & Noste 1985

Burn Severity Index (5 classes):

Burn Severity Class

Buff-breasted flycatchers more Buff-breasted flycatchers more common in burned woodlandscommon in burned woodlands

0

10

20

30

40

50

60

70

1.5-2.0 2.0-5.0 5.0-10.0 >10.0

Height above Ground (m)

Per

cen

t C

over

(T

otal

) x

0 (n = 36)

1 (n = 11)

2 (n = 20)

3 (n = 20)

4 (n = 19)

Percent cover of vegetation at 4 heights differed among 5 burn-severity classes

Burn-severity Class

1) Burn-severity index provides information on severity but not frequency of previous fire events

Potential Problem:

If observed declines in BBFLs are due to decreased fire frequency, then….

1) Recently burned forests more likely to be colonized by BBFLs

2) Survey points with BBFLs more likely to have evidence of recent fires

3) Survey points with BBFLs more likely to have evidence of more frequent fire events

1916 Fire

1865 Fire

1842 Fire

14 survey routes with

BBFLs

14 survey routes

without BBFLs

tpaired = 1.8P = 0.048

Routes with BBFLs had more frequent fires

with BBFLs without BBFLs

1) not all trees scar during a fire2) don’t know the severity of previous fires

Potential Problems:

Summary of results

Fire severity Fire frequency

Why didn’t BBFLs colonize our 5 recently (<10 yrs) burned survey routes?

1) recruitment and immigration insufficient?

2) low-severity burns insufficient?

3) BBFLs may require >10 years to locate and colonize burns

Why didn’t BBFLs colonize our 5 recently (<10 yrs) burned survey routes?

1) recruitment and immigration insufficient?

2) low-severity burns insufficient?

3) BBFLs colonize areas >10 yrs post-burn?

MEXICO

• Conducted surveys in 7 mt. ranges

adjacent to Huachucas & Chiricahuas

Last BBFL recorded 18 Aug. 1911

We detected:2 in 20004 in 2004

5 (incl. pair) in 2005

What’s driving BBFLs to re-colonize the Rincon Mountains after 89 year absence?

70% of bird survey points burned (56%

burned severely)

Ignition Points

Burn Perimeters

Ignitions and Fire History, Rincon Mountains, Saguaro National Park

Mica Mt

Rincon Peak

Tucson

Carr Canyon

<1976<197644

1983198399

199519951717

200420042323

19761976FireFire

Santa Catalina Mountains

Bullock Wildfire (2002) & Aspen Wildfire (2003)Bullock Wildfire (2002) & Aspen Wildfire (2003)

Santa Catalina Mountains

>90% burned Variation in burn severity

Future work

• Continue monitoring BBFL populations in Arizona (and New Mexico?)

• Determine reproductive success to assess quality of habitat

• Determine status of Mexican population

For more information:For more information:

Conway, C. J., and C. Kirkpatrick. 2007. Effect Conway, C. J., and C. Kirkpatrick. 2007. Effect of forest fire suppression on buff-breasted of forest fire suppression on buff-breasted flycatchers. flycatchers. Journal of Wildlife Management Journal of Wildlife Management 71:445-457.71:445-457.

Kirkpatrick, C., C. J. Conway, and D. LaRoche. Kirkpatrick, C., C. J. Conway, and D. LaRoche. 2007. Range expansion of the Buff-breasted 2007. Range expansion of the Buff-breasted Flycatcher (Flycatcher (Empidonax fulvifronsEmpidonax fulvifrons) into the ) into the Rincon Mountains, Arizona. Rincon Mountains, Arizona. Southwestern Southwestern NaturalistNaturalist 52: 149-152. 52: 149-152.

Kirkpatrick, C., C. J. Conway, and P. B. Jones. Kirkpatrick, C., C. J. Conway, and P. B. Jones. 2006. Distribution and relative abundance of 2006. Distribution and relative abundance of forest birds in relation to burn severity in forest birds in relation to burn severity in southeastern Arizona. southeastern Arizona. Journal of Wildlife Journal of Wildlife ManagementManagement 70:1005-1012. 70:1005-1012.

For more information:For more information:

www.ag.arizona.edu/srnr/research/www.ag.arizona.edu/srnr/research/coop/azfwru/cjc/coop/azfwru/cjc/

• click on links to “Research”click on links to “Research”and “Past Project #8” and “Past and “Past Project #8” and “Past Project #9”Project #9”

kirkpatr@email.arizona.edukirkpatr@email.arizona.edu