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T H E BIRDS OF T H E A L D E R M E N I S L A N D S

Susan M . Fogarty* and M . E . Douglasf

S U M M A R Y

O f the 48 species of birds recorded from the Aldermen Islands, 21 were landbirds. Fantails, silvereyes, bellbirds and red-crowned parakeets were the most abundant. Six other species were recorded for the first time.

I N T R O D U C T I O N

A survey of the bird-life o f the Aldermen Islands was carried out by the authors from 20 to 30 May 1972, and an abundance list of landbirds was compiled for .each island. As camp was made on Ruamahua-iti, this island received the most attention, and thus records from there are more detailed and probably more accurate. A species list including both seabird and landbird faunas is also contained in this paper.

Middle Chain may have been used by previous observers to include both Half and Hernia Islands (see Hayward, 1973).

P R E V I O U S W O R K

From 1921-27 Sladden and Falla (1928) meticulously recorded twice yearly the birdlife o f the Aldermen Islands. This was continued privately by Sladden until 1951. The islands were revisited in February 1950 by Sladden, Falla and L . C . Be l l , which is documented in Falla (1953).

Wildlife Branch files hold the following unpublished records of visits: Sladden, Falla, and L . C . Bell in March 1951; Blackburn in early July 1958; L . C . Bell in December 1958; L . C . Bell in Apr i l 1959; B . D . Bell et al. in September 1959; and Adams in November 1967.

A survey of the vegetation of the group was made in 1958 by Cochrane (1962).

The Sugarloaf rock, 3.2 km north-west of the main group, was visited in March 1970 by Falla (1970).

* CI- Secondary Teachers' College, Auckland. t Department of Zoology, University of Auckland.

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P A R T I: A B U N D A N C E O F L A N D B I R D S

M E T H O D

(1) Ruamahua-iti was divided up into five separate areas. Time allowed only a single survey in each area, and the results obtained were contributed to the total for the islands. (2) Middle Island was divided into three parts, and single surveys were made in each part on separate days. Because of the precipitous terrain some areas could not be reached and hence were not surveyed; these areas were the south-west end and the high central peaks of Middle Island. (3) Ruamahua-nui, Hernia and Hongiora were covered by single surveys only. (4) Half Island was not visited by the authors and birds recorded there were seen en route to other islands of the group.

The survey technique used is as follows: Abundance counts were made while walking more or less directly through the area. A three minute stop was made after every ten minutes walking. Individual birds seen and heard were recorded.

R E S U L T S

The landbird abundances on the Aldermen Islands are presented in Table I. These figures represent counts for every ten minutes walking and for each three minute stop.

Table I: Counts of birds seen and heard for each 13 minute walk/stop interval on various islands of the Aldermen group.

Ruamahua Ruamahua-iti n u i

Species Hernia

Silvereye Fan tail Red-crowned

parakeet Tui Blackbird Chaffinch Bellbird Grey warbler Yellowhammer Goldfinch Brown quail House sparrow

90 90

75 2

14 7

45 7 I

41 62

48 3

1 1 7

28 4 3

1 2 2

Half Middle Hongiora

27 29 41 21

12 28

3 4 5 23 7 10 1 1

9

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DISCUSSION

O f all the islands of the group Ruamahua-iti received the most attention, and therefore the figures given in Table I for this island would tend to be more accurate than those for many of the other islands.

The recording of birds by recognition of their vocalizations is most important in abundance surveys. However, the reduced activity of many of the birds in May must be an important contributing factor to undercounting. This would particularly affect the counts of grey warbler, which remained relatively silent compared to those on Red Mercury Island in August, 1971. Furthermore, undercounting was inevitable for several reasons: (a) The noise created when moving through areas of thick scrub tends to make secretive species more wary, and they may not be counted. Other birds, such as blackbirds, may give alarm calls when disturbed, while fantails, on the other hand, may be attracted by disturbances, (b) The number of parakeets, silvereyes and finches may have been underestimated because the vegetation often prevented flocks of these species from being seen, (c) On some surveys, probably because of wind and rain, the numbers of birds recorded were lower than expected.

Possible duplication in counts of individual birds was avoided mainly by the more or less direct route taken.

Species such as starling and kingfisher have not been included in the abundance count because they frequent coastal cliffs, which were often inaccessible.

Red-crowned parakeet, bellbird, goldfinch, chaffinch and harrier were seen to fly between the islands of the group. These movements may vary considerably with the seasons.

P A R T II: A N N O T A T E D SPECIES LIST

Eudyptula minor (little blue penguin) Two birds were seen at sea between Tairua and the Aldermen on each

crossing. They breed on the Aldermen in small numbers (Sladden and Falla, 1928), sometimes in association with Sphenodon punctatus (tuatara) (B. Sladden, 1954).

Diomedea exulans (wandering albatross) One juvenile seen off the Aldermen in November (Adams, 1967).

Diomedea melanophris (black-browed mollymawk) One immature seen offshore in September, and two immatures seen in June

by Blackburn (1958).

Diomedea bulleri (Buller's mollymawk) Three recorded en route in June by Blackburn (1958). Macronectes giganteus

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Macronectes giganteus (giant petrel) One bird seen at sea off Ruamahua-nui. Previously recorded in July 1958 by

Blackburn (1958).

Daption capensis (cape pigeon) Two recorded at sea by Blackburn (1958), one recorded by B . D . Bell et al.

(1959).

Pterodroma macroptera (grey-faced petrel) The most abundant petrel on the Aldermen Islands. Burrows were found on

all islands visited in the group. In general, burrows were most concentrated (approximately 2 0 4 5 per 100 square metres) on gentle slopes under tall trees with little undergrowth, and less dense (0-20 per 100 square metres) where there was a thick covering of low trees. However, on the low-lying Hongiora, burrows were of a high density (approximately 40-42 per 100 square metres), under low Coprosma and Hymenanthera. On Middle Island burrows were found mainly on the ridges. The lower slopes in many places were covered in thick vegetation and loose scree from rock-falls.

In fine weather the first birds made landfall on Ruamahua-iti between 10 and 20 minutes after sunset. By midnight arrival numbers had gradually decreased. Leaving began in the early morning and was completed half an hour before sunrise. During the day single burrows often contained one bird and sometimes two. No eggs were seen.

Twenty-one birds were found dead on the Aldermen group, of which 8 had died when their wings or legs became entangled in small vines and roots at their burrow entrances. Of the remaining 13 no apparent cause of death could be seen. Two were presumably predated upon by harriers. Two beach-wrecked specimens were found.

Pachyptila spp. (prions) Six seen on May 20, and 11 on May 30, between Tairua and the Aldermen.

Previously recorded by B . D . Bell et al. (1959) and Blackburn (1958).

Puffinus carneipes (flesh-footed shearwater) None seen, but Sladden and Falla (1928) recorded about 100 birds breeding

at the eastern end of Hongiora.

Puffinus bulleri (Buller's shearwater) None seen. Sladden and Falla (1928) state that they are frequently seen in

the vicinity o f the Aldermen (in summer), but are unlikely to breed.

Puffinus griseus (sooty shearwater) None seen, but Sladden and Falla (1928) recorded about 12 burrows on

Ruamahua-nui, and Adams (1967) heard them on Hongiora.

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Puffinus gavia (fluttering shearwater) Small numbers heard on most nights. On May 28, on a particularly rough

night, 8 were recorded in a 400 square metre area just above the camp. Sladden and Falla (1928) record burrows on the north-western slopes of Ruamahua-iti and the south-eastern face of Middle Chain.

Puffinus assimilis (allied shearwater) A single bird was seen on two different nights. This species may breed on

Ruamahua-iti. Ten birds banded by Adams (1967).

Pelagodroma marina (white-faced storm petrel) None seen. There is a large breeding colony on Hongiora, which Sladden and

Falla (1928) considered to be one of the largest in New Zealand waters. This species commences breeding in October and the young leave during February (Sladden and Falla, 1928). The birds are absent from about late A p r i l to early August, their destination unknown (Falla, Sibson, and Turbott , 1966).

Pelecanoides urinatrix (diving petrel) 151 birds seen on May 20, and 27 on May 30, between Tairua and

Ruamahua-iti. Seven birds were found in burrows amongst roots of Mesembryanthemum about camp, and others were heard on the cliff face above. Recorded as breeding on Middle Chain (Sladden and Falla, 1928), and on Hongiora (Adams, 1967; Blackburn, 1958).

Sula bassana (gannet) Up to 12 seen fishing offshore each day. A breeding colony was observed on

the Sugarloaf rocks 2 miles north-east of Hongiora by B . Sladden in the early 1920s. This colony numbered about 10 pairs when visited by R . A . Falla in 1926. No further visits were made until 1947 when W. Gilliver found no sign of gannets on the rocks, (Fleming and Wodzicki , 1952).

Phalacrocorax carbo (black shag) One recorded on May 20 between Tairua and Ruamahua-iti. Single birds seen

on two occasions near Ruamahua-nui. Not previously recorded.

Phalacrocorax varius (pied shag) Up to 14 birds at a time seen roosting amongst unoccupied nests on a

pinnacle off Middle Island. Small numbers seen each day fishing.

Phalacrocorax sulcirostris (little black shag) One seen flying off Ruamahua-iti on May 22 and off Middle Island on May

23. Previously unrecorded.

Phalacrocorax melanoleucos (little shag) One little pied seen at sea between Tairua and the Aldermen on May 20 and

30. Three of the white-throated phase were seen off Middle Island on May 23.

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Egretta sacra (reef heron) Sladden and Falla (1928) recorded a single bird in flight off Hongiora. Also

previously recorded on Ruamahua-nui and Middle Chain by B . D . Bell et al. (1959). May breed.

Circus approximans (Australian harrier) A t least three range between Ruamahua-iti, Ruamahua-nui and Middle Island.

Two others were seen over Hongiora. One was found dead at high tide mark on Ruamahua-nui. Two predated corpses of grey-faced petrel could well be attrib­uted to this species. May breed.

Synoicus ypsilophorus (brown quail) Observed on both Ruamahua-iti and Ruamahua-nui in small numbers.

Stercorarius parasiticus (Arct ic skua) Sladden and Falla (1928) note that they are frequently seen near the

white-fronted tern colony in the breeding season.

Larus dominicanus (southern black-backed gull) Mainly juveniles seen at sea on each crossing. Only small numbers seen off the

Aldermen. Sladden and Falla (1928) recorded one pair breeding on the summit of a rock off Ruamahua-iti.

Larus novaehollandiae (red-billed gull) About 40 birds were seen on each crossing, and at least 32 roosted each night

on a flat rock between Ruamahua-iti and Middle Island. Breeding colonies were recorded on a steep rock off Ruamahua-iti and on the Sugarloaf rocks by Sladden and Falla (1928).

Hlydroprogne caspia (Caspian tern) One seen flying off Ruamahua-iti on May 22. Not previously recorded.

Sterna striata (white-fronted tern) Occasional birds seen offshore. Sladden and Falla (1928) recorded breeding

colonies on a steep rock off Ruamahua-iti and on the Sugarloaf rocks.

Procelsterna cerulea (grey ternlet) None seen. In January 1970 Mr D . Pomeroy of Wellington discovered large

numbers of grey ternlet roosting and feeding about the Sugarloaf rocks. R . A . Falla in a following trip estimated about 200 to be present. Whether ternlet has bred on these rocks or not in recent years is uncertain as the area has not received much critical attention. However it is unlikely that there was any noticeable establishment in the years between 1921 and 1951 when the late B . Sladden cruised the area and recorded meticulously more than twice yearly (Falla, 1970).

Columba livia (rock pigeon) One "racing-pigeon" washed up on Ruamahua-iti.

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Cyanoramphus novaezelandiae (red-crowned parakeet) Common on all islands. Frequently seen flying from island to island. Sladden

and Falla (1928) state that they feed on karo, mahoe and flax seeds.

Ninox novaeseelandiae (morepork) Heard occasionally by Sladden and Falla (1928).

Halycon sancta (New Zealand kingfisher) Small numbers seen all around the coast. Not recorded before 1951 (Sladden

and Falla, 1951).

Anthus novaeseelandiae (New Zealand pipit) None seen. In 1925 Sladden and Falla (1928) recorded this species as fairly

common from hilltop to boulder beach. Only small numbers were recorded by Wildlife visits in the late 1950s. This decline may have been caused by regener­ation of the vegetation.

Prunella modularis (hedge sparrow) None seen. Recorded on Hongiora by Blackburn (1958), and on

Ruamahua-nui by B . D . Bell et al. (1959).

Bowdleria punctata (North Island fernbird) Recorded in 1925 by Sladden and Falla (1928) as being abundant in the thick

undergrowth of native broom, manuka, and flax but not in tall scrub. This "open meadowland" vegetation is now almost absent, having been replaced by tall scrub. Thus no fernbird were seen (see also Falla, 1953).

Gerygone igata (grey warbler) Few birds were heard to call. Two were seen flying out over the sea close to

the shore, possibly insect-catching.

Rhipidura fuliginosa (North Island fantail) The most common bird in the Aldermen group. 21 were seen in a flock

engaged in acrobatics off a high cliff on Ruamahua-nui. On Ruamahua-iti, one was seen feeding over a pool which contained mosquitos, flying ants, hymenopterans, and hemipterans.

Turdus philomelos (song thrush) None seen. Recorded on Hongiora by B . D . Bell et al. (1959).

Turdus merula (blackbird) Well-established throughout the Aldermen group.

Zosterops lateralis (silvereye) Flocks of 6 to 10 birds common. Seen feeding on mahoe seeds, as well as

foraging on the ground.

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Anthornis melanura (bellbird) Observed drinking from small pools along the rocky shore, and feeding on

mahoe seeds and insects among the bark of pohutukawa. One male bird was seen four times doing a humming-bird like flight, while "chort l ing".

Prosthemadera novaeseelandiae (tui) Not previously recorded. Two seen on Ruamahua-iti and three on

Ruamahua-nui.

Emberiza citrinella (yellowhammer) Not previously recorded. Three seen on Ruamahua-nui in a small patch of

Muehlenbeckia.

Fringilla coelebs (chaffinch) Plentiful on Hongiora. Seen flying between islands of the group.

Carduelis carduelis (goldfinch) Not previously recorded. Small flocks seen on Ruamahua-iti and Hongiora.

There is some movement between the islands of the group as 10 were seen passing between Middle Island and Ruamahua-iti on May 26. From Hongiora on May 27, 2 were seen to fly out o f sight directly towards the mainland.

Passer domesticus (house sparrow) One seen on Ruamahua-iti and four on Half Island. Previously recorded by

L . C . Bell (1959).

Sturnus vulgaris (starling) Frequently seen around cliffs of all the islands.

A C K N O W L E D G E M E N T S

The authors wish to thank the Wildlife Branch, Department o f Internal Affairs, for making available their unpublished records; all Field Club members who contributed observations; and Mr P .F . Jenkins for critically reading the manuscript.

REFERENCES

Unpublished reports on the Aldermen Islands, Wildlife Branch file 46.29.13:

Sladden, B.; Falla, R.A.; Bell, L.C. 1951. Blackburn, A. 1958. Bell, L.C. 1958; 1959. Bell, B.D.; Bowie, E.; Sibson, R.B.; Blackburn, A.; Leggard, T.; Hogg, M . ; Sibson, R. 1959. Adams, G.P. 1967.

39

Cochrane, G.R. 1962: The Aldermen Islands: A remnant of primaeval New Zealand. Trans. Roy. Soc. N.Z. Botany 1: 331-41.

Falla, R.A.; Sladden, B. 1928: Aldermen IslandsN.Z.J.Sci.Tech. 9 (5): 282-90. Falla, R.A. 1953: Change and adjustment in plant and animal communities. Report of

second annual meeting of N.Z. t'col. Soc. : 3-4. Falla, R.A.; Sibson, R.B.; Turbott, E.G. 1966: " A field guide to the birds of New Zealand"

Collins, London, 254pp. Falla, R.A. 1970: Grey ternlets in the Bay of Plenty Notornis 17 (2): 83-86. Fleming, C.A.; Wodzicki, K .A. 1952: A census of the gannet in New Zealand Notornis 5 (2):

39-78. Fogarty, S.M.; Douglas, M.E. 1972: The Birds of Red Mercury Island Tane 18: 107-116. Hayward, B.W. 1973. Auckland University Field Club Scientific Camp, Aldermen Islands,

May 1972. Tane 19 (this volume) Sladden, B. 1954. "Summarised classified notes" Notornis 5 (7): 212.

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