TANE 27, 1981

BIRDS OF CUVIER ISLAND

by P.J. Bellingham*, T.G. Lovegrove**, J. McCallum, S.E. Pitt and I.C. Southey

* Department of Botany, University of , Private Bag, Auckland t Department of Zoology, University of Auckland, Private Bag, Auckland Department of Geology, University of Auckland, Private Bag, Auckland **RD 2, Waiotira, Northland

SUMMARY

Sixty species of have been recorded from Cuvier Island and surrounding waters during a series of expeditions from 1974 to 1980.

INTRODUCTION

Cuvier lies 40 km east of Cape Colville, the northern tip of the . The island is approximately 200 ha in area, with 180 ha forming the forested flora and fauna reserve, while the remainder is the grazed pastureland of the lighthouse station (see Fig. 1). Observations were compiled during a number of visits made by T.G.L. from 1974 to 1979,1.C.S. in August 1979, J. McC. in November to December 1979, and by P.J.B., J.McC, S.E.P. and I.C.S. during the Auckland University Field Club scientific trip from 21 to 26 May, 1980. Species nomenclature follows the Ornithological Society of (1970). Apart from kiore (Rattus exulans), the island is free of introduced mammalian predators. Since goats and cats were exterminated in the early 1960s, the forest understory has regenerated rapidly making suitable habitat for a number of native birds. By 1968 Cuvier was considered suitable for , and in January of that year 29 birds were released. In 1974, red-crowned parakeets were introduced. Recent ornithological studies included those of Blackburn (1967), McLean (1975), Jenkins (1976), Reed (1976), Lovegrove (1980), McLean and Jenkins (1980) and O'Callaghan (1980).

23 SPECIES LIST

Little blue penguin (Eudyptula minor). Penguins were often heard around the coast at dusk and nesting cavities located under boulders and in rock crevices near the shore. Wandering albatross (Diomedea exulans). A regular visitor to the seas around Cuvier in winter. Black-browed mollymawk (Diomedea melanophris). A common winter visitor to the waters of Cuvier Island from May to October. Yellow-nosed mollymawk (Diomedea chlororhynchus). This species is more numerous in New Zealand waters than previously thought and is often seen in the and around Cuvier during winter. Shy mollymawk (Diomedea cauta). A few seen offshore between May and August 1979. Giant petrel (Macronectes giganteus). Present in surrounding waters between June and November. Cape pigeon (Daption capensis). A frequent visitor during winter. Odd birds were often seen in large feeding flocks of gulls, shearwaters and prions offshore. Grey-faced petrel (Pterodroma macroptera). The breeding colonies on Cuvier Island may contain several thousand individuals. The birds arrive in April and May to clean burrows and court. Spectacular aerial displays by pairs occur in May, most eggs have hatched by August and the colonies are deserted by January. Figure 1 shows the distribution of burrows on Cuvier (density was not estimated due to haphazard spacing). Measurements of captured birds are shown in Table 1. Sexing by cloacal inspection was difficult in late May, as most breeding pairs had departed for an approximate 64 day "honeymoon" period (M.J. Imber pers. comm.). Most of our figures given in Table 1 are significantly smaller than data published by Imber (1971) as the majority measured were young birds as well as non-breeders. Kermadec petrel (Pterodroma neglecta). Since 1976 (Reed 1976), a Kermadec petrel, probably the same , has visited Cuvier every summer. It was seen during November and December 1979 and was photographed. This individual is a dark- phased bird and its visits followed a regular daily pattern. It usually appeared in late afternoon and circled the occupied gull colony. Often it was chased by the gulls and terns when it overflew their nest-sites. In shape, size and appearance, this petrel was remarkably like a young pomarine skua (Stercorarius pomarinus). Cookilaria petrels (Pterodroma spp.). The "kek-kek-kek" calls of cookilarias are often heard over the

24 Fig. 1. Distribution of grey-faced petrels burrows, Cuvier Island, May 1980, shown by shaded regions. island on summer nights. Cook's petrels breed 30 km away on Great and Little Barrier Islands, while Pycroft's petrels (Pterodroma pycrofti) breed 25 km away at the outer . Cook's petrel (Pterodroma cooki). Several individuals have been picked up after striking the lighthouse. Fairy prion (Pachyptila turtur). Large flocks of prions, most probably this species, were seen offshore during winter. Black petrel (Procellaria parkinsoni). Occasionally seen in surrounding waters, especially during summer. Flesh-footed shearwater (Puffinus carneipes). Frequently seen offshore in flocks during summer. Buller's shearwater (Puffinus bulleri). The most numerous shearwater seen off Cuvier during summer. Flocks may number hundreds of individuals. Sooty shearwater (Puffinus griseus). A few pairs breed on Cuvier. A bird sitting on an egg in a burrow on the Radar Point Ridge was captured and photographed in January 1977. Fluttering shearwater (Puffinus gavia). Present in the seas around Cuvier throughout the year. Allied shearwater (Puffinus assimilis). Regularly seen around Cuvier Island either alone or in small groups. They do not breed on islands inhabited by rats. A single, freshly used burrow was found on top of Scott's Monument, a small rat-free stack in Fairchild Bay, during May 1980 and was presumed to belong to this winter-breeding shearwater. White-faced storm petrel (Pelagodroma marina). Numerous in surrounding waters during summer. Diving petrel (Pelecanoides urinatrix). Numerous around Cuvier throughout the year. Gannet, (Sula bassana). Common around Cuvier throughout the year. Black shag (Phalacrocorax carbo). One seen in May 1979. Pied shag (Phalacrocorax varius). A small colony at Radar Point has been occupied for some years. A count in July 1979 showed 16 birds and 5 occupied nests. Little shag (Phalacrocorax melanoleucos). Seen in May 1980. White-faced heron (Ardea novaehollandiae). 2 in the damp valley behind the lighthouse station on 2.3.79. Mallard (Anas platyrhynchos). One in the North-west Bay stream on 22.1.75, while a pair inhabited

26 the valley behind the lighthouse station for most of February 1979. Harrier (Circus approximans). Odd birds are often noted over the island, but no nests have been found. Cast pellets show that kiore and small birds comprise a large portion of their diet. Red-necked stint (Calidris ruficollis). A single bird, probably completing its migration to New Zealand, was seen on several occasions in the valley behind the lighthouse station during October 1979. Black-backed gull (Larus dominicanus). One or two pairs may breed along the coast of Cuvier during summer. Red-billed gull (Larus novaehollandiae). From numbers given in previous papers (Gurr and Kinsky 1965, Blackburn 1967, Reed 1976) and from accounts by the lighthouse keepers, there are fewer gulls nesting on Cuvier Island than in the past. In 1979, only 74 occupied nests were found (numbers of eggs and chicks in these nests are shown in Table 2). In 1978, it is possible that no chicks were reared at all and the colony was practically deserted by 6.12.78. Caspian tern (Hydroprogne caspia). One seen in July 1979. White-fronted tern (Sterna striata). A small colony breeds successfully every year at Cuvier. 25 occupied nests were counted in November 1979 and contents of eggs and chicks are given in Table 3. New Zealand pigeon (Hemiphaga novaeseelandiae). Probably at least 10 pairs on Cuvier Island. A late nest found on 14.5.79 was incubated until 20.5.79 and then abandoned. Kaka ( meridionalis). A regular visitor to Cuvier, probably from Great Barrier where it is numerous. Red-crowned parakeet (Cyanoramphus novaezelandiae). Numerous, especially on grassy slopes. There has been a dramatic increase in numbers since Reed (1976). Yellow-crowned parakeet (Cyanoramphus auriceps). Occasional birds and pairs recorded during 1979 and may have originated from Little Barrier or the Coromandel Ranges. Shining cuckoo (Chalcites lucidus). Common during summer. One bird over-wintered during 1979. Long-tailed cuckoo (Eudynamis taitensis). A few birds reach the island every summer. A lack of suitable host species means these cuckoos probably do not breed on Cuvier. Sometimes they are "mobbed" by small flocks of the larger passerines. Morepork (Ninox novaeseelandiae).

27 Moreporks are very rare on Cuvier Island, despite a good food supply of kiore. During 12 visits to the island between 1974 and 1980, only one morepork has been seen. Spine-tailed swift (Chaetura caudacuta). 9 birds seen on 11.12.79 soaring high over the island. Kingfisher (Halcyon sancta). Common in the forest and along the coast. Nest holes have been found in the rotten boughs of old pohutukawas (Metrosideros excelsa). Skylark (Alauda arvensis). A few present all year round. On Cuvier, there is no sign of the seasonal movements which occur on the mainland during winter. Welcome swallow (Hirundo tahitica). Present throughout the year. Although breeding may be expected in the buildings of the lighthouse station, no nests have been found. It is probable that nesting has occurred in caves along the rocky coastline. Pipit (Anthus novaeseelandiae). Occasionally seen on the fern slopes above North-west Bay. Hedge sparrow (Prunella modularis). Rather sparingly distributed throughout the forest. Songs have been heard throughout the year at various sites on the island. (Gerygone igata). Common in the bush, but not as numerous as the fantail. Fantail (Rhipidura fuliginosa). Numerous, especially obvious during winter, when flocks of 20 or more young birds gather in sunlit forest clearings to "hawk" insects. The fantail-saddleback feeding association has been described by McLean (1975) and can be seen at any time of the year. Song thrush (Turdus philomelos). A few pairs in the forest and several birds around the lighthouse station. Blackbird (Turdus merula). Common along the forest margin near the pastureland and in the lighthouse station garden. In the forest, this bird is scarce and wary. (Zosterops lateralis). Common in the forest. Flocks of 40-50 may be seen during winter. Bellbird (Anthornis melanura). Possibly the most common passerine on Cuvier. Breeding probably begins in late September as fledged independent young were observed by 8.11.78. (Prosthemadera novaeseelandiae). It is difficult to understand why the tui is so scarce on Cuvier when it is so numerous on islands such as Hen. However the tui is clearly more dependent on nectar than the bellbird (Gravatt 1969) and Cuvier's forest does not supply the continuity necessary to sustain a population. It seems there is a minor invasion of tuis to the island in

28 May to June each year when kohekohe (Dysoxylum spectabile) flowers. There were at least 20 birds on the island during May—June 1979. Chaffinch (Fringilla coelebs). Distributed through the forest and in the open areas near the lighthouse station. Site-attached males begin singing in late July — early August. Yellow hammer (Emberiza citrinella). A few pairs breed on the steep grassy slopes around the north-east side of the island. Occasional males were heard singing during the summer. Greenfinch (Carduelis chloris). A few birds may be present during the summer, but the greatest numbers occur in winter when large flocks visit the island (e.g. 60 on 10.8.78). Goldfinch (Carduelis carduelis). A few birds present on the island throughout the year and probably breed. Redpoll (Acanthis flammea). Usually seen as a small, high flying silhouette giving its characteristic "chi-chi-chi" call. Odd birds have been recorded throughout the year, but no singing territorial males have been noted. House sparrow (Passer domesticus). Common around the lighthouse station where they nest in karo (Pittosporum crassifolium) hedges. Starling (Sturnus vulgaris). Probably 100 birds present. They are usually seen over the pastureland; post-breeding flocks may be conspicuous. They frequently enter the forest. Myna (Acridotheres tristis). A small flock of up to 6 birds frequent the paddocks behind the lighthouse station. Saddleback (Philesturnus carunculatus). Numerous - a grid count in February 1980 indicated a population of about 800 birds on Cuvier (C.R. Veitch pers. comm.). Established territories have an area of about 0.4 ha. Many birds are very long-lived, and pair-bonds may last 10 years or more. The oldest bird on record is a male observed in November 1979 (banded as an adult on Hen Island in 1968) who still occupied the same territory which it took up soon after release on Cuvier in 1968 (Jenkins 1976, Lovegrove 1980).

DISCUSSION

Cuvier Island has considerable value as a sanctuary for a number of species. This can be attributed to its remoteness, limited forest destruction during its past history and the successful removal of goats

29 and cats in the early 1960s. The saddleback transfer from Hen Island in 1968 was so successful that the population on Cuvier has reached saturation and is now used as a source of birds for liberations to other islands. At present, the only Procellariiformes which breed on Cuvier Island are sooty shearwaters (rare) and grey-faced petrels (common). Similar islands within the same region have colonies of allied, flesh-footed and fluttering shearwaters, Cook's, diving and Pycroft's petrels and white- faced storm petrels. Many of these species persist on kiore - inhabited islands. It is reasonable to suggest that the length of time rats have been on an island may be judged by their deleterious effect on the fauna and the degree to which they have modified it. Perhaps the low number of petrel species on Cuvier Island can be attributed to a longer occupancy by kiore than on neighbouring islands. Feral cats and goat browsing before the 1960s may also be responsible for Cuvier's depauperate seabird fauna of only two species. With these pressures removed, it is possible that some seabirds will return to breed. Falla (1934) recorded mottled petrels (Pterodroma inexpectata) on Cuvier (now locally extinct) while cookilaria petrels are occasionally heard flying overhead at night. Court (1978) has discussed possible forest successions on Hen Island, in which pohutukawas may be replaced by other forest. At present, the canopy on Cuvier is dominated by pohutukawa and the regenerating understory may support a large food biomass for native passerines, especially saddlebacks, bellbirds and fantails. It appears that the saddleback density on Cuvier is greater than that on Hen Island. However, as the vegetational community becomes more mature, the number of some bird species may decrease. Other species reported from Cuvier included tattlers (Tringa sp.) by Reed (1976), while Falla (1934) states that pied tits (Petroica macrocephala) were present. The latter have not been recorded since and are presumed to have succumbed to feral cats, while the tattlers may have reached Cuvier as their first New Zealand landfall while on migration. Other species occurring sporadically for the island include New Zealand falcons (Falco novaeseelandiae) in the early 1960s (Blackburn 1967) and a sooty tern (Sterna fuscata) in 1961 (Merton 1962). The avian species composition is tentatively subdivided as: -18 native; breeding confirmed -10 introduced; breeding confirmed -14 native; possibly vagrants - 3 introduced; possibly vagrants -15 native; in surrounding waters A reasonably high number of breeding species exist on Cuvier and the fact that two of these (saddleback and red-crowned parakeet) have been introduced by man suggests that more species may become 30 Table 1. Measurements of grey-faced petrels on Cuvier Island, May 1980, giving means with standard errors and range (n=20).

Culmen 36.4 ± 0.3 mm 33.5 -- 38.' mm Bill width 15.9 ± 0.3 mm 14.0 -- 17.9 mm Bill depth 18.4 ± 0.2 mm 16.5 -- 20.4 mm Tarsus 45.4 ± 0.5 mm 42.6 -- 51.8 mm Tail 122 ± 2 mm 108 -- 138 mm Wing 321 ± 3 mm 300 -- 346 mm Weight 524 + 7 g 460 -- 580 g l

Table 2. Contents of 174 occupied red-billed gulls' nests examined at Cuvier Island on 24.11.79.

3 5 • • • • • Number of 2 31 1 • • • • 1 27 19 2 • • •

eggs 0 • 32 24 25 1 7

0 12 12 1 alive &1 dead alive dead

Number of chicks

Table 3. Contents of 35 occupied white-fronted terns' nests examined at Cuvier Island on 24.11.79

2 2 •

Number of ( 22 2

eggs Q • 9

0 1 Number of chicks

established on the island in the future. The abundance of introduced species may be related to the degree to which the native vegetation has been modified. With the bush regenerating to produce a climax community, these species may decline. Closing the manned lighthouse station will probably allow regeneration in the area which has been maintained in pasture. This would mean fewer habitats for introduced species. As seen by the richness and diversity of its bird fauna, the continued preservation of Cuvier Island from excessive disturbance is justified.

ACKNOWLEDGEMENTS

The authors would like to thank all those who provided assistance in the field, especially M.A. Potter and F.R. Darker. J.R. Hay for critically reading the manuscript; and K. Bellingham for typing.

31 REFERENCES

Blackburn, A. 1967: A brief survey of Cuvier Island. Notornis 14:3-8 Court, D.J. 1978: Forest regeneration on Hen Island. Tane 24:103-118 Falla, R.A. 1934: The distribution and breeding habits of petrels in northern New Zealand. Records of the Auckland Institute and Museum 1 (5): 245-259. Gravatt, D.J. 1969: The feeding ecology of honey eaters (Aves-Meliphagidae) on Little Barrier Island. M.Sc. thesis, University of Auckland. 94 p. Gurr, L. & Kinsky, F.C. 1965: The distribution of breeding colonies and status of the red- billed gull in New Zealand and its outlying islands. Notornis 12:223-240. Imber, M.J. 1971: Filoplumes of petrels and shearwaters. New Zealand Journal of Marine and Freshwater Research 5:396-403. Jenkins, P.F. 1976: The social organisation and vocal behaviour of the saddleback Philesturnus carunculatus refusater{Aves). Ph.D. thesis, University of Auckland. 204 p. Lovegrove, T.G. 1980: The saddleback pair bond. M.Sc. thesis. University of Auckland. 93 p. McLean, I.G. 1975: Aspects of the social and feeding ecology of the fantail, Rhipidura fuliginosa. M.Sc. thesis, University of Auckland, 138 p. McLean, I.G. & Jenkins, P.F. 1980: Breeding and development of the Rhipidura fuliginosa Notornis 27:105-113. Merton, D.V. 1962: Sooty tern at Cuvier Island (short note). Notornis 10:40. O'Callaghan, A.P. 1980: Use of space by the Philesturnus carunculatus rufasater (Aves). M.Sc. thesis. University of Auckland. 96 p. Ornithological Society of New Zealand (Kinsky, F.C. Convener). 1970: "Annotated Checklist of the Birds of New Zealand". A.H. & A.W. Reed, Wellington. 96 p. Reed, S.M. 1976: Report on Cuvier Island, January 1976 (short note). Notornis 23: 259- 262.

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