Breeding populations of Adelie Penguins in the Pacific Sector.
No. of breeding
Region Location pairs (approx.)
Bellingshausen Sea Charcot Island 50
Peter I Island 20
Marie Byrd Land Mt Siple ? small
Maher Island ? small
Mathewson Point 30,000
Worley Point 10,000
Cruzen Island 100
Ross Island Cape Royds 4,000
Cape Bird South 15,800
Cape Bird Middle 3,200
Cape Bird North 40,100
Cape Crazier West 151,500
Cape Crozier East 28,400
Ross Sea Islands Beaufort Island 53,700
Franklin Island West 55,300
Franklin Island East 1,200
Terra Nova / Wood Bays Inexpressible Island 28,000
Terra Nova Bay 11,600
Edmonson Point 2,400
Coulman Island Cape Anne 500
Coulman Island South 22,600
Coulman Island Middle 5,500
Coulman Island North 1,900
Daniel Peninsula Cape Jones 200
Mandible Cirque 19,500
Cape Phillips 4,400
Hallett Peninsula Cape Wheatstone 2,300
Cape Cotter 49,500
Cape Hallett 57,600
Possession Islands Foyn Island 41,900
Possession Island 157,600
Adare Peninsula Downshire Cliffs 22,600
Cape Adare 240,000
Pennell Coast Duke-of-York Island 4,600
Sentry Rock 80
Unger Island 150
Nella Island 200
Oates Land Aviation Is. "Conical Island" 150
Aviation Is. "Dome Island" 150
Aviation Is. "South West Island" 700
Balleny Islands Sabrina Island 4,400
Chinstrap Island 2,400
South West Promontory 300
Cape Davis 550
Cape Cornish 500
Totals 45 colonies > 1,076,000
Three species of petrels that breed near to or north of the Subtropical Convergence regularly forage close to the Antarctic pack ice in summer : they are the Sooty Shearwater (Puffinus griseus), Short-tailed Shearwater (Puffinus tenuirostris) and Mottled Petrel (Pterodroma inexpectata.) These are joined by many sub-antarctic species of procellariids which migrate south to forage chiefly on the summer swarms of Antarctic krill (e.g., Harper, 1973,1987; Croxall, 1984).
Since the review of Young (1981), the main advances in knowledge about seabirds in the Antarctic Sector of the Pacific have been concerning their status and conservation (Harper et al., 1984; Schlatter, 1984) and their marine ecology in summer (Ainley et al., 1984). However, there is still virtually nothing known about the winter life of these birds.
Aerial reconnaissance and photography have been used in the Ross Sea region since 1981 to determine the breeding locations of Adelie Penguins and to count the numbers of nests occupied during the early incubation period (Taylor and Wilson, 1982; Wilson and Taylor, 1984). Despite years of exploration in the region, new colonies continue to be found (Wilson and Thomas, 1988).
Since 1985, radio transmitters have been attached to penguins at Cape Bird on Ross Island to track them at sea. During the incubation stage, most penguins went northwards beyond the range of the tracking equipment (100 km) for most of their time at sea (Ward et al., 1985; Davis et al., 1988). During the chick-feeding stage, most penguins stayed in McMurdo Sound within 5 km of the colony, but a few disappeared around the north end of Ross Island more than 10 km away (Sadleir, 1987). This project is the beginning of new developments which may extend to tracking the critical winter movements of penguins. It may also provide useful data in the event of an increase in shipping or air traffic for tourism, fishing, oil or mineral exploration, with consequent increased risk of serious oil pollution.
The New Zealand plateau is the only large continental platform adjacent to the Antarctic Sector of the Pacific, and consists of a substantial area of relatively shallow seas (depth less than 2,000 m) which allows a complex mixing of waters about its margins. The New Zealand plateau contains six subantarctic island groups. These islands, together with the three main islands of New Zealand, support a seabird diversity unmatched anywhere else on Earth. Accounts of these islands and their avifauna are given in Clark and Dingwall (1985) and Fraser (1986). About 60 seabird species breed in the New Zealand Province, but only about half of these breed south of the Subtropical Convergence (Table 10.2). The remainder are subtropical and/or transequatorial species and lie outside the scope of this chapter. Apart from the Taiko (Pterodroma magentae), a subtropical species on the Chatham Islands, perhaps the most interesting finding in recent years was the discovery of the South Georgia Diving Petrel (Pelecanoides georgicus) nesting in consolidated sand dunes at Codfish Island, off Stewart Island, by Imber and Nilsson (1980). The presence of warm subtropical waters in Foveaux Strait makes the find of this subantarctic species all the more remarkable.
This small (3.3 km2) group of two low-lying and mainly forest-covered islands, and several small islets and rocks, has no introduced mammals and remains virtually in a natural state. At 48°02'S, 166°33'E, The Snares lie just north of the Subtropical Convergence. The seabirds which breed there represent a mingling of subtropical and subantarctic elements.
Twenty-one species of seabirds breed on The Snares. The endemic Snares Crested Penguin (Eudyptes robustus) has a population of 30,000-50,000 birds in 133 scattered colonies (Warham, 1974). Two species of albatross breed at the islands, about 700 pairs of Buller's Mollymawk on Northeast and Broughton Islands and
Alert Stack (Warham and Bennington, 1983), and smaller numbers of Salvin's Mollymawk (D. salvini) on the outlying islets of the Western Chain. Warham and Wilson (1982) estimated the total population of Sooty Shearwaters (Puffinus griseus) breeding on The Snares to be 2,750,000, or a bird population "similar in size to that of the whole of the seabird population of Britain and Ireland". The food resources required to feed this biomass of 4.4 x 10s kg must also be impressive, although studies to investigate this remain to be carried out. Fenwick (1978) reported four species of birds and six species of fish feeding on euphausiid and amphipod swarms near The Snares during the summer of 1976/77.
Another common species on The Snares is the Southern Diving Petrel (.Pelecanoid.es urinatrix chathamensis). Other breeding birds are the Snares Cape Pigeons (Daption capense australe), Mottled Petrel (Pterodroma inexpectata), Broad-billed Prion (Pachyptilla vittata), Fairy Prion (P. turtur), Fulmar Prion (P. crassirostris), Antarctic Tern (Sterna vittata), Red-billed Gull (Larus scopulinus), and Southern Skua (Catharacta lonnbergi).
The University of Canterbury has a biological station on the islands and scientific parties have visited there regularly since 1961. Research on Snares Islands seabirds has included studies on the Snares Crested Penguin (Stonehouse, 1971; Warham, 1974), Buller's Mollymawk (Richdale and Warham, 1973; Warham and Bennington, 1983; Warham and Fitzsimons, 1987), Mottled Petrel (Warham et al., 1977), Sooty Shearwater (Warham et al., 1982; Warham and Wilson, 1982), Snares Cape Pigeon (Sagar 1979,1986), Antarctic Tern (Sagar, 1978). There are also several general accounts of the island's birdlife (Warham, 1967a; Warham and Keeley, 1969; Fleming and Baker, 1973; Horning and Horning, 1974; Sagar, 1977a, b; Miskelly, 1984).
The uninhabited Auckland Islands (50°40'S, 166°10'E) extend for 52 km from north to south and for 35 km from east to west, and have a land area of about 620 km2. The group consists of two large, partly forested islands with peaks over 600 m, four smaller islands, and numerous small islets and stacks. Although there are pigs, goats, cats and mice on the main island — and cattle, rabbits and mice on a few others — the group as a whole still supports a rich and plentiful birdlife.
These islands are a known breeding station for 25 species of seabird — including 3 penguins and 16 albatrosses and petrels. The colonial nesting Rockhopper Penguin (Eudyptes c. chrysocome ) is the most numerous penguin with 5-10,000 pairs breeding (Bell, 1975). There are also considerable numbers of the solitary nesting Yellow-eyed Penguin (Megadyptes antipodes) on Adams, Enderby and Rose Islands where there are no introduced predators. The Erect-crested Penguin (E. sclateri) also breeds in small numbers on the Auckland group. There are over 13,500 pairs of Wandering Albatross (Diomedea exulans) and 64,000 pairs of White-capped Mollymawk (D. cauta steadi ) — the former mainly on predator-free Adams Islands and the latter mainly on Disappointment Island (Robertson, 1975). Smaller numbers of Southern Royal Albatross (D. epomorphora), Light-mantled Sooty Albatross (Phoebetria palpebrata), and Northern Giant Petrel (Macronectes halli) also nest on various islands in the group.
Crevice or burrow nesting petrels are the Snares Cape Pigeon, White-headed Petrel (Pterodroma lessoni), Antarctic Prion (Pachyptila desolata), Subantarctic Fulmar Prion (P. crassirostris eatoni), White-chinned Petrel (Procellaria aequin-octialis), Sooty Shearwater, Subantarctic Little Shearwater (P. assimilis elegans), Grey-backed Storm Petrel (Garrodia nereis), White-faced Storm Petrel (Pelago-droma marina maoriana), Black-bellied Storm Petrel (Fregetta tropica), Subantarctic Diving Petrel (Pelecanoides urinatrix exsul), and South Georgia Diving Petrel.
The Southern Skua, Southern Black-backed Gull (Larus dominicanus), Red-billed Gull, Antarctic Tern and White-fronted Tern (Sterna striata) also breed at the islands. There is one marine cormorant, the endemic Auckland Island Shag (Leucocarbo campbelli colensoi) which nests in small scattered colonies on cliff tops and ledges, and fishes inshore waters.
The lack of permanent bases or regular expeditions has affected the type of research carried out on the Auckland Islands. Seabird studies have been confined to surveys, banding (movement) studies, and the incidental collection of data on breeding and other aspects (Falla, 1965; Bell, 1975; Robertson, 1975; van Tets, 1975; Falla et al., 1979; Anonymous, 1985c; Penniket et al., 1986). Greater opportunities for in-depth research on Auckland Island seabirds may occur in the near future. Much more detailed ecological information is needed on the different seabird species using the islands. Such information is essential to help formulate sound management policies, not only for these important Nature Reserves but also for the surrounding seas from which the birds derive their food.
The Campbell Islands, situated at 52°33'S, 169°E, are the most southerly of the islands on the New Zealand Plateau. They comprise Campbell Island (113 km2), which reaches 567 m a.s.l. and a number of small islets and stacks. The vegetation is mainly tussock grassland, shrubland and herbfield. The plant cover and wildlife of the main island are much modified by past farming ventures and the presence of feral sheep, cats and Norway rats. Only the small offshore islets remain in a natural state.
Three penguin species breed on the islands. The most common species is the Rockhopper Penguin which previously bred in millions (Bailey and Sorensen, 1962) but more recently their numbers have declined drastically (Moors, 1986). Reasons for this are uncertain but are probably connected with food supplies at sea. Small numbers of Erect-crested Penguins also breed amongst the Rock-hoppers. Campbell Island has the southernmost population of the Yellow-eyed Penguin, with several hundred pairs nesting behind beaches and sheltered sloping shores on many parts of the island.
The island is the main nesting locality of the Southern Royal Albatross. The breeding population has been increasing since the 1930s and now numbers about 10,000 pairs (Taylor et al., 1970; Dilks and Wilson, 1979). The Light-mantled Sooty Albatross nests on the coastal cliffs and offshore stacks, and a few Wandering Albatrosses also breed on the main island (Fig. 10.3). Campbell is also the main breeding station of the New Zealand Black-browed Mollymawk (D. m. impavidd), and of the Grey-headed Mollymawk (D. chysostoma) in the South Pacific, but the numbers of both these species appear to have declined recently, perhaps from the same factors affecting Rockhopper Penguins. Northern Giant Petrels nest in small colonies on several parts of Campbell Island and on offshore islets. The numbers of these scavengers have also declined in recent years, a trend that is probably linked to the large decline in the island's penguin and elephant seal populations.
The burrowing petrel populations of the Campbell Islands have been severely reduced by predation from cats and rats over the past 100 years. Medium-sized petrels still breeding in small numbers on the main island include the Snares Cape Pigeon, Grey Petrel, White-chinned Petrel, and Sooty Shearwater (Bailey and Sorensen, 1962). However, it is only on the small outlying islets that there are any numbers of White-chinned Petrels, Sooty Shearwaters, Grey-backed Storm Petrels, Black-bellied Storm Petrels, and Subantarctic Diving Petrels (Robertson, 1980; Foggo and Meurk, 1981). There is a breeding population of about 2,000 pairs of the endemic Campbell Island Shag (Leucocarbo campbelli campbelli) that nest on the cliff ledges on the main island and on several offshore islets (van Tets, 1980). Southern Skuas, Southern Black-backed Gulls, Red-billed Gulls and Antarctic Terns are the other seabird species breeding at the Campbell Islands.
Campbell Island was the site of continuous coast-watching expeditions during World War II and has had a manned meteorological station since 1946. Conse-
quently, more biological investigations have been carried out there than at most other New Zealand subantarctic islands. Unfortunately, with the exception of J.H. Sorensen in the 1940s, no professional ornithologist was attached to these expeditions for more than a few summer months until 1984. Published research on Campbell Island seabirds includes studies on the Rockhopper Penguin (Moors, 1985), Southern Royal Albatross (Sorensen, 1950a; Westerskov, 1959,1963; Taylor et al., 1970; Dilks and Wilson, 1979), Light-mantled Sooty Albatross (Sorensen, 1950b), Campbell Island Shag (van Tets, 1980), as well as many more general surveys and reviews (Westerskov, 1960; Bailey and Sorensen, 1962; Falla, 1965; Kinsky, 1969; Robertson, 1980).
This group is situated at 49°42'S, 178°47'E and consists of Antipodes Island (20.2 km2), six small offshore islets and several stacks. The main island consists of an elevated plateau with hills reaching about 400 m a.s.l. Small, sparse patches of low shrubs form the only woody vegetation, and the plant cover is predominantly tussock grassland and fern. There has been little human impact on the islands, and mice — which are confined to the main island — are the only introduced mammals.
Twenty species of seabirds, including 2 penguins and 15 petrels, breed at the islands. Erect-crested Penguins and Rockhopper Penguins occur in over 80 mixed colonies on all suitable parts of the coastline, and on Bollons, Archway and Windward Islands (Fig. 10.4).
About 1,500-1,800 pairs of Wandering Albatross breed on the main island (Warham and Bell, 1979) and 150 pairs of Black-browed Mollymawk (D. melano-phrys melanophrys) on Bollons Island (Robertson, 1985a). Numerous Light-mantled Sooty Albatrosses nest on steep coastal slopes and cliff ledges, and c. 320 pairs of Northern Giant Petrels nest in small scattered colonies. Of the burrow-nesting petrels, the White-headed Petrel is the most abundant, and the White-chinned Petrel and the winter-breeding Grey Petrel are also common. The Subantarctic Little Shearwater nests on the offshore islets in vast numbers. Imber (1983) considered that the Antipodes group has the largest population of this species in the South Pacific — in excess of 100,000 pairs. Other petrels breeding in smaller numbers are the Subantarctic Diving Petrel, Grey-backed Storm Petrel, Black-bellied Storm Petrel, Snares Cape Pigeon (c. 300 pairs), Subantarctic Fairy Prion, Soft-plumaged Petrel (Pterodroma mollis), and Sooty Shearwater. Other breeding seabirds are the Southern Skua and the Antarctic Tern. Rather surprisingly there are no shags, but the surrounding waters are much deeper than around the other New Zealand subantarctic islands and it is probable that no suitable niche exists for them.
There have been several major expeditions to the islands since 1950. Resulting publications on seabirds include a general account of the birdlife (Warham and Bell, 1979) as well as the results of studies on the Southern Skua (Moors, 1980), the lesser petrels (Imber, 1979,1983), and the Antarctic Tern (Sadleir et al., 1986).
The Bounty Islands (1.3 km2) are a group of more than 20 small granite islands and rocks situated at 47°45'S, 179°03'E. The islands are all less than 75 m a.s.l. and the only land plants are lichens and green algae.
Seven species of seabirds breed on the Bounty Islands. According to Robertson and van Tets (1982), there are about 115,000 pairs of Erect-crested Penguins, 76,000 pairs of Salvin's Mollymawks, many thousands of Fulmar Prions, small numbers of Snares Cape Pigeon and Antarctic Terns and fewer than 600 pairs of the endemic Bounty Island Shag (Leucocarbo campbelli ranfurlyi). Three predatory or scavenging species — Northern Giant Petrels, Southern Black-backed Gulls and Southern Skuas — are found in some numbers at the Bounty Islands during the summer but do not breed there. Their nearest breeding sites are at the Antipodes Islands, 250 km away.
Few ornithologists have made more than a fleeting visit to the Bounty Islands, and only one scientific party has camped ashore. Consequently, most accounts of the birdlife are in general terms (Oliver, 1955; Darby, 1970; Falla et al., 1979; Robertson and van Tets, 1982; Anonymous, 1985c).
The Chatham Island archipelago (963 km2) is situated at 44°00'S, 176°30'W, 800 km east of New Zealand's South Island. It consists of two large islands (Chatham and Pitt) and about 10 smaller islands as well as many stacks and rocks.
As a result of centuries of human occupation, the vegetation and birdlife of the larger islands have been seriously depleted. Feral farm stock, pigs, cats, rats and mice occur on Chatham Island, and all these pests except for rats are also on Pitt Island. Fortunately, all other islands and islets are now uninhabited and free of introduced mammals, and provide safe refuge for most of the surviving seabird species. Several of the smaller islands and large parts of Pitt Island are now Nature Reserves. The islands lie within the Subtropical Convergence. The seabird fauna of the islands is therefore made up of species of warmer waters, species of cooler waters, and local endemics — most of which feed in the productive waters along the convergence zone.
One species of penguin and 16 petrels breed at the islands. The predominantly warm-water species include the Blue Penguin (Eudyptula minor), Northern Royal Albatross (Diomedea sanfordi), Northern Buller's Mollymawk (D. bulleri platei), and the Black-winged Petrel (Pterodroma nigripennis). Local endemic petrels are the Chatham Island Mollymawk (D. eremita ) with a total population of about 4,000 pairs breeding on the Pyramid (Robertson, 1985b), the recently re-discovered and extremely rare Chatham Island Taiko (Pterodroma magentae) with a total population of perhaps only 40 birds (Crockett, 1985), and the Chatham Island Petrel (P. axillaris) which is also rare and breeds only on South East Island (Imber, 1985). Petrels breeding at the Chathams which also breed further south in the subantarctic are the Northern Giant Petrel, Snares Cape Pigeon, Broad-billed Prion, Fairy Prion, Fulmar Prion, Sooty Shearwater, Subantarctic Little Shearwater, Grey-backed Storm Petrel, White-faced Storm Petrel, and the Southern Diving Petrel (Pelecanoides urinatrix chathamensis).
There are two endemic shags, the Chatham Island Shag (Leucocarbo c. carun-culatus) and the Pitt Island Shag (Stictocarbo punctatus featherstoni). Other breeding seabirds are the Southern Skua, Southern Black-backed Gull, Red-billed Gull and White-fronted Tern.
Although much fieldwork has been carried out on Chatham Island seabirds by both privately funded and government expeditions over the last 20 years, few results have been published in detail. Notable exceptions are Dawson's (1973) work on Albatross and mollymawk colonies, and Young's (1978) study of the Southern Skua. Other papers and short notes published on Chatham Island seabirds since Fleming's (1939) standard work deal with survey results (Bell, 1954), Northern Royal Albatross and Northern Buller's Mollymawk (Robertson, 1974), Northern Giant Petrel (Hemmings and Bailey, 1985), Chatham Island Taiko (Crocket, 1979), Black-winged Petrel (Merton, 1984), various small petrels (Imber, 1978), subfossil petrel bones (Bourne, 1964,1967; Scarlett, 1976), and the Chatham Island Shag (Morris, 1977). Much original information on the different species has also been published in field guides and books on New Zealand birds (e.g., Oliver, 1955; Falla et al., 1979; Anonymous, 1985c).
The most southerly of the islands in the New Zealand Province is Macquarie Island, situated at 54°37'S, 158°54'E. The island lies on the Macquarie Ridge which is separated from the New Zealand Plateau by the Emerald Basin. It has four species of penguins, including one endemic subspecies of the Macaroni Penguin (Eudyptes chrysolophus schlegeli), 13 species of procellariids, an endemic subspecies of shag, the circumpolar Southern Skua, the Black-backed Gull and the Antarctic Tern. The lack of endemicity in Macquarie Island seabirds reflects the dominant circumpolar elements in its avifauna.
Since the island's discovery in 1810, Macquarie has suffered severely from the impact of human exploitation by early sealers, and the associated introduction of predators and vermin such as mice, rats, cats, dogs, rabbits, and the Stewart Island Weka (Gallirallus australis scotti). These imports have devastated the island's marine avifauna to the extent that the Grey Petrel (Procellaria cinerea) has been exterminated as a breeding species, and the population of most of the remaining species have been greatly reduced (Falla, 1947; Jones, 1980; Brothers, 1984).
Studies on Macquarie birds have included those of the Royal Penguin (Shaughnessy, 1970, 1975), Rockhopper Penguin (Warham, 1963), the feeding ecology of the Giant Petrels (Johnstone, 1977) and White-headed Petrel (Warham, 1967b). The status and conservation of the Macquarie Island birds has recently been reviewed by Rounsevell and Brothers (1984).
The Magellanic District of the Atlantic Province embraces the southern fjords and archipelagoes of Chile where Murphy's (1936) pioneering treatise on South American seabirds remains the definitive work (see also Johnson, 1965). As recently as 1984, Roberto Schlatter of Valdivia University, Chile, remarked, "few ornithologists have conducted searches for and surveys of breeding colonies, and more work in this vast and inaccessible area is urgently needed." Jehl (1973) has discussed the distribution of marine birds in Chilean waters in winter, and, more recently, the Totorore expedition made valuable seabird observations in the southern Chilean fjords in 1983, including the discovery of Thin-billed Prions (Pachyptila belcheri) breeding on Ilsa Noir and a new colony of 200,000 Sooty Shearwaters breeding on Ilsa Guafo (Clark et al., 1984a, b).
The dominant influence in this region is the Peru Current which carries sub-antarctic waters northwards along the west coast of South America to just south of the equator. This cool-water system enables 18 species of chiefly subantarctic seabirds to nest in Chile (Murphy, 1936; Schlatter, 1984). The breeding list includes four species of penguin, including one endemic (Sphenicus magellanicus) to the Fuegian coasts, nine species of petrels (one endemic), five species of cormorants (one endemic), the Chilean Skua, and four species of gulls and terns (two endemic). Boswell and Maclver (1975) reviewed the breeding biology and ecology of Magellanic Penguins, which are numbered "in millions, possibly tens of millions".
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