T A N E 26,1980

T H E M A M M A L S , B I R D S , R E P T I L E S A N D F R E S H W A T E R F I S H O F T H E E A S T E R N I S L A N D G R O U P O F T H E

B A Y O F I S L A N D S

B y R . A . Hi tchmough* and J . McCallum * 17 Jubilee Ave., Devonport, Auckland 9

t Department of Geology, University of Auckland, Private Bag, Auckland

S U M M A R Y

Two freshwater fish, one lizard, three mammal and forty b ird species (sixteen breeding) were noted on twenty five islands visited in the eastern B a y of Islands Group.

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

The eastern island group of the B a y of Islands was visited from 4 January to 13 January 1980 and observations were made on the freshwater and terrestrial vertebrates. A description of the islands is given by H a y w a r d (1980).

The islands have been visited previously by Wildl i fe Service parties (Anderson 1978) but apart from some bird records in Notornis (Edgar 1966, 1978; G u r r and K i n s k y 1965), there are no known publications on the vertebrate fauna.

M E T H O D S

D a y trips were made to most of the islands in the group from a base camp on Urupukapuka Island. Te A o and Urupukapuka Islands were also searched at night. F i s h were captured at night by hand. Lizards , found by searching suitable habitats, were captured by hand, identified, measured and released. The status of b ird species were noted. Pumpkin-baited snap traps were set on a number of islands, as shown in Table 1.

A N N O T A T E D S P E C I E S L I S T

The distribution and status of vertebrates seen is summarised in Table 2 and an annotated list is given below. Nomenclature follows M c D o w e l l (1978) for fish, H a r d y (1977) for skinks, Ornithological Society of New Zealand (1970) for birds and Wodzick i (1950) for mammals.

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Pisces Anguilla sp.

Several eels were seen in a mud-bottomed stream in Urupukapuka Bay . Galaxias fasciatus

Common in the stream in Urupukapuka Bay .

Repti l ia Leiolopisma smithi

Fair ly common in the l imited suitable habitat on some islands, but not on other, similar islands. Measurements of animals caught are shown in Table 3.

Aves L i t t l e blue penguin, Eudyptula minor.

Seen in surrounding waters and in burrows on several islands. Grey-faced petrel, Pterodroma macroptera.

Unoccupied burrows, presumably belonging to this species, were found on five of the smaller and less-modified islands. Flesh-footed shearwater, Puffinus carneipes.

One storm-wrecked on Motuarohia Island. D i v i n g petrel, Pelecanoides urinatrix.

One found washed ashore on Motukiekie Island. Gannet, Sula bassana.

Relatively common in surrounding waters. Black shag, Phalacrocorax carbo.

Several birds frequented the group. Pied shag, Phalacrocorax varius.

Common. U p to thirty pairs were nesting at Oneura B a y on Urupukapuka Island. L i t t l e shag, Phalacrocorax melanoleucos.

Rare. Two pairs were nesting near the pied shags at Oneura B a y . White-faced heron, Ardea novaehollandiae.

Two single sightings made during this vis it . Reef heron, Egretta sacra.

Regularly seen, but not abundant. A pair were nesting in a shallow cave on Mahenot i t i Island. Grey or mallard duck, Anas superciliosa or A. platyrhynchos.

A flock, of about 20 individuals, was seen f lying over Urupukapuka Island one evening. Harrier , Circus approximans.

A pair were suspected breeding on Okahu Island in a raupo swamp or extensive rank grasses. They ranged to other nearby islands. B r o w n quail , Synoicus ypsilophorus.

Smal l coveys were present on the larger islands.

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Pukeko, Porphyrio porphyrio. One pair found nesting on Urupukapuka Island.

Variable oystercatcher, Haematopus unicolor. Several pairs inhabited the group and a nest was found on

Pakatahi Island. New Zealand dotterel, Charadrius obscurus.

One pair probably breeding on Okahu Island and others seen on Urupukapuka Island. Black-backed gull , Larus dominicanus.

Frequently seen. Breeding was proved or suspected on a number of islands. Red-billed gull , Larus novaehollandiae.

Common. A colony was situated on Poroporo Island, but a large number of empty nests and few juveniles seen may indicate an unsuccessful season (see under mammals, below). Caspian tern, Hydroprogne caspia.

One b ird seen. White-fronted tern, Sterna striata.

U p to 100 birds were roosting on Ngatokararangi Island and ranged over surrounding waters. Rock pigeon, Columba livia.

Four birds, possibly domesticated, seen on Motuarohia Island. Shining cuckoo, Chalcites lucidus.

Heard call ing on several islands. Morepork, Ninox novaeseelandiae.

Single b ird heard on Urupukapuka Island. M a y be present on other islands. Kingfisher, Halcyon sancta.

Occurred on several islands and found breeding on Pakatahi Island. Skylark , Alauda arvensis.

Present on the larger islands. A nest was found on Urupukapuka Island. Welcome swallow, Hirundo tahitica.

Frequent around the majority of islands and breeding on at least four islands. P ip i t , Anthus novaeseelandiae.

One b ird seen on Motukiekie Island. Hedge sparrow, Prunella modularis.

O d d individuals located on several islands. Grey warbler, Gerygone igata.

Common on many of the islands. Fantai l , Rhipidura fuliginosa.

Found on six islands. A family group was observed on Motuarohia Island.

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Song thrush, Turdus philomelos. Present on the larger islands; nests were found on Motukiekie and

Waewaetorea Islands. Blackbird , Turdus merula.

Individuals inhabited many of the islands and breeding was confirmed on three islets. Silvereye, Zosterops lateralis.

Widely distributed in reasonable numbers on most islands in the group. Yellow hammer, Emberiza citrinella.

Occasionally seen and heard. Chaffinch, Fringilla coelebs.

Found in reasonable numbers on the larger islands. Greenfinch, Carduelis chloris.

Rare. Located sparingly on four islands. Goldfinch, Carduelis carduelis.

Common on many islands and breeding on Urupukapuka Island. House sparrow, Passer domesticus.

Regularly seen. Starl ing, Sturnus vulgaris.

Rare and sparsely distributed through the group. M y n a , Acridotheres tristis.

Common on the majority of islands in the group.

M a m m a l i a Rattus sp.

Traps set on several islands failed to catch rats (see Table 1). The body of a R. norvegicus was found on Motuarohia Island. Rats were reported by residents to have been present on Urupukapuka Island. Stoat, Mustela ermina.

N o mustelids were seen by members of the party. However stoats were kil led by campers at Urupukapuka B a y and by a camper's cat on Waewaetorea Island shortly before our arrival . Stoats were also reported by residents at Otehei Bay . Cat, Felix catus.

Cats were kept by campers and residents on several of the islands. A n abandoned animal was reported to be running wi ld on Urupukapuka Island.

There was evidence of the presence of predators at the red-billed gull colony on Poroporo Island. Only four chicks and one nest wi th eggs were seen, although nearly 100 adults were present. Several empty nests, including some wi th the remains of opened eggs were found, and there were several well-picked skeletons, some apparently fresh, in the vic inity. The bones themselves did not appear to have been chewed.

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D I S C U S S I O N

A l l the islands visited have been modified in the past by M a o r i and European activities. This is reflected in the poor diversity of vertebrates present and the low representation of native species.

B o t h fish species are native, but are diadromous with a marine dispersive larva and are therefore well-adapted to invading new habitats as they become available. The reptile fauna is extremely poor and the only species, L. smithi, occupies rocky beaches which are relatively safe from interference. The number of b ird species is reasonable. This may be due to the different habitats available and the size of the island group. However, many of the birds noted are introduced and the number of both pelagic species and rails was poor.

ACKNOWLEDGEMENTS

The authors would like to thank members of the party who contributed their observations, especially C.A. and M.A. Fleming; Dr J . L . Craig for critically reading the paper; and J . J . Liddle for typing.

R E F E R E N C E S

Anderson, G.L . (Compiler! 1978: Unpublished Wildlife Service island survey of the eastern Bay of Islands Group. Department of Internal Affairs, Wellington.

Edgar, A .T . 1966: Welcome swallows in New Zealand, 1958-1965. Notornis 13(1): 27-60. Edgar, A .T . 1978: The reef heron (Egretta sacra) in New Zealand. Notornis 25(1): 25-58. Gurr, L. and Kinsky, F.C. 1965: The distribution of breeding colonies and status of the

red-billed gull in New Zealand and its outlying islands. Notornis 12(4): 223-240. Hardy, G.S. 1977: The New Zealand Scincidae (Reptilia: Lacertilia); a taxonomic and

zoogeographic study New Zealand Journal of Zoology 4(3): 221-325. Hayward, B.W. 1980: Offshore Island Research Group scientific trip to the eastern Bay

of Islands Group, January 1980. Introduction and Acknowledgements. Tane 26: 107-113.

McDowell, R.M. 1978: "New Zealand freshwater fishes: a guide and natural history." Heinemann Educational, Auckland. 230p.

Ornithological Society of New Zealand (Kinsky, F.C.Convener) 1970: "Annotated checklist of the birds of New Zealand". A . H . and A.W. Reed, Wellington. 96p.

Wodzicki, K .A . 1950: Introduced mammals of New Zealand. New Zealand Department of Scientific and Industrial Research Bulletin 98. Government Printer, Wellington. 255p.

Table 1. Distribution of snap-trapping effort in the eastern Bay of Islands Group.

Island No. of trap-nights Rats caught

Mahenotiti 8 0 Orerewainui 20 0 Paeroa 12 0 Poroporo 26 0 Split 6 0 Te Ao 19 0 Urupukapuka 75 0 Whakairipiha 8 0

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Table 2. Distribution and abundance of birds and lizards and mammals in the eastern Bay of Islands Group, 5 to 14 January, 1980. 0 O - common - seen in numbers wherever there was suitable habitat. • • - few - seen in smaller numbers or absent from some suitable habitat. T V - rare - only odd specimens seen, w - beach wrecked, d -domestic, r - reported by residents. Open symbol - not found breeding, but may possibly do so. Closed symbol - breeding confirmed.

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Pisces Anguilla sp. Galaxias fasciatus Rep ti lis

Leiolopisma smithi Ave*

Little blue penguin

Grey-faced petrel Flesh-footed shearwater

Diving petrel

Gannet

Black shag

Pied shag

Little shag White-faced heron

Reef heron Duck lap.I

Harrier

Brown quail

Pukeko Variable oystercatcher N.Z. dotterel Black-backed gull Red-billed gull Caspian tern White-fronted tern Rock pigeon Shining cuckoo Morepork Kingfisher Skylark

Welcome swallow Pipit Hedge sparrow

Grey warbler Fan tail

Song thrush

Blackbird Silvereye

Yellow hammer Chaffinch Greenfinch

Goldfinch House sparrow Starling

Myna Mammalia Rattus norvegicus Rattus sp. Mustela ermina Felix catus

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common in surrounding waters

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Table 3. Number of L. smithi in sample, mean weights and mean snout-vent lengths (SVL), with standard deviations and ranges for each island.

Island No. in sample weight (g) S V L (mm)

Motukiekie 6 3.6±0.7(2.8 - 4.8) 5 4 ± 3 (50 - 59). Poroporo 3 2.1 + 0.7(1.5 - 2.5) 4 6 ± 3 (44 - 47). Urupukapuka 2 5.2±0.5(5.0 - 5.5) 6 2 ± 3 (24 - 63). Waewaetorea 1 6.0 59.

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