Antarctic Petrel Thalassoica antarctica Scientific name definitions

40–46 cm; 510–765 g; wingspan 100–110 cm (1 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ). Unmistakable pattern on upperparts in flight. Characteristic and contrasting dark and white pattern, both in flight and at rest, unique in seabirds. Adult has dark chocolate-brown hood and upperparts to rump, darkest when fresh, paler brown with some paler blurry scaling in worn plumage , when can show an ill-defined pale collar  ; uppertail-coverts and tail white except sharply-defined blackish to dark brown terminal bar on tail ; upperwing has dark chocolate-brown anterior half, including primary-coverts and outer primaries, rear half white, including inner primaries (with small dark tips) and a few of their innermost coverts, all greater and tips of median coverts, and all secondaries except dark chocolate-brown tips forming narrow trailing edge broken on inner primaries; underwing-coverts  white except obvious dark chocolate-brown bar on leading edge, broadest on inner wing, the remiges having narrow dark trailing edge like above, but outer primaries also white except small dark tips; transition between dark hood and white underparts is not sharp, can start at mid breast, but sometimes central area is diffusely pale up to chin, with dark area extending via breast-sides to axillaries; iris very dark; bill  dusky brown with dull olive tinge over most of sides; legs greyish, with more or less flesh or pinkish tinge. Female slightly smaller in most measurements, except perhaps tail (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Unmistakable if well seen, but Daption capense may be rather similar at first glance, especially from below; dark speckles on underparts and pattern of rump and inner upperwing prevent confusion. Juvenile as adult but has all-black bill, and feathers are slightly and narrowly fringed paler, especially on mantle and inner upperwing-coverts (1 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ).

Southern Ocean, breeding in Antarctica and on surrounding islands.

Marine; prefers open waters in vicinity of pack ice, especially in areas with icebergs; style of flight was considered probably unsuitable to pelagic foraging over long distances, but it seems to travel further offshore than Fulmarus glacialoides and satellite-tracked birds have conducted foraging trips of up to 3000 km during incubation period (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), while even when open water is available for foraging closer to nest-sites during chick-rearing period, the adults still undertake long-range feeding trips (3 Creuwels, J.C.S., Engelhard, G.H. and van Franeker, J.A. (2005). Do different petrel species feed their chick differently? Alauda. 73(3): 234. Close ); largely pelagic outwith breeding season. Nests on snow-free cliffs and rock faces, often north-facing (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), mostly along coast or on offshore islands, but up to 350 km inland (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) and at least 700 m above sea-level (4 Bassett, J.A., Woehler, E.J., Ensor, P.H., Kerry, K.R. and Johnstone, G.W. (1990). Adélie Penguins and Antarctic Petrels at Mount Biscoe, Western Enderby Land, Antarctica. Emu. 98(1): 58–60. Close ).

Little known; dispersive within normal extent of floating ice, rarely straying far; could be partially migratory. Some birds move N in winter, reaching Antarctic Convergence and sometimes beyond (48–55º S versus 62º S in summer) (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), e.g. regularly recorded around South Georgia at this season, between Jun and Aug (5 Prince, P. A., and J. P. Croxall (1996). The birds of South Georgia. Bulletin of the British Ornithologists’ Club 116(2):81–104. Close ); others remain around edge of ice. Vagrant to the Falklands (Jun, Sept and Feb) (6 Woods, R. W. (1988). The Birds of the Falkland Islands. Anthony Nelson, Oswestry, England. Close , 7 Gregory, P. (1994) Notes on new and scarce birds in the Falkland Islands 1988–1990. Bulletin of the British Ornithologists' Club 114: 12–20. Close ), South Africa (Mar–Oct, to 33º S) (8 Chadwick, P.I. (1991). Third specimen record of the Antarctic Petrel Thalassoica antarctica for Africa. Marine Orn.. 19(1): 69–70. Close , 9 Ward, V.L. (1998). Antarctic Petrel Thalassoica antarctica records from the Prince Edward Islands and South Africa. Marine Orn.. 26(1): 86–87. Close ), New Zealand  (where beached birds surveys recorded unusually high totals of 77 and 18 birds in 1978 and 1991, respectively, with most recoveries between 1990 and 2000 in month of Sept) (10 Powlesland, R.G. and Powlesland, M.H. (1993). Seabirds found dead on New Zealand beaches in 1991, and a review of Morus and Sula species recoveries, 1943 to 1991. Notornis 40(4):233–245. Close , 11 Wood, J. (2004). Annual and monthly patterns in recoveries of beach-wrecked Procellariiformes from Southland, New Zealand 1990-2000. Notornis 51(2):103–112. Close ) and Tasmania, with old records from extreme S Chile (12 Marín, M. (2004). Lista Comentada de las Aves de Chile. Annotated Checklist of the Birds of Chile. Lynx Edicions, Barcelona. (In English and Spanish.) Close ).

Mostly krill (Euphausia superba); also fish (Pleuragramma antarcticum) (13 van Franeker, J.A. (1994). Summer diet of Antarctic fulmarine petrels. Journal of Ornithology. 135(1): 183. Close ), squid (Gonatus antarcticus), crustacea and medusae (jellyfish) (14 Norman, F.I. and Ward, S.J. (1992). Foods and aspects of growth in the Antarctic Petrel and Southern Fulmar breeding at Hop Island, Rauer Group, East Antarctica. Emu. 92(4): 207–222. Close ). In one study, the fish Electrona antarctica comprised 62% of the diet (15 Ainley, D.G., Ribic, C.A. and Spear, L.B. (1993). Species-habitat relationships among Antarctic seabirds: a function of physical or biological factors? Condor. 95(4): 806–816. Close ). Feeds mainly by surface-seizing, but also by surface-plunging and contact-dipping; also known to dive both from air and from surface. Foraging trip duration during chick-rearing is shortened by parents with older chicks and prolonged by parents with younger chicks, probably in response to the chick’s food demand (16 Varpe, Ø., Tveraa, T. and Folstad, I. (2004). State-dependent parental care in the Antarctic petrel: responses to manipulated chick age during early chick rearing. Oikos. 106: 479
–488. Close ). Often associates with baleen and other large whales (Balaenoptera acutorostrata, Megaptera, Hyperoodon) (17 Hodges, C. L., and E. J. Woehler (1994). Associations between seabirds and cetaceans in the Australian sector of the southern Indian Ocean. Marine Ornithology 22(2):205–212. Close , 18 Orgeira, J.L. (2004). Asociaciones entre aves marinas y cetáceos en el Océano Atlántico Sur y Antártida. Orn. Neotropical. 15(2): 163–171. Close ) and seabirds, e.g. Pagodroma (especially in winter) (1 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ) and Arctic Tern (Sterna paradisaea); concentrations of up to 5000–6000 birds recorded around whaling ships.

Mostly silent at sea (1 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ). Antagonistic and sexual displays at nest-site are accompanied by a “kook-kook-kook...” or similar churring, clucking and cackling calls, all of which are stronger and more resonant than calls of Fulmarus glacialoides (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 1 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ).

Starts Nov, following main return to colony in Oct and complete pre-laying exodus from late Oct until third week of Nov (19 Creuwels, J.C.S., van Franeker, J.A., Doust, S.J., Beinssen, A., Harding, B. and Hentschel, O. (2008). Breeding strategies of Antarctic Petrels Thalassoica antarctica and Southern Fulmars Fulmarus glacialoides in the high Antarctic and implications for reproductive success. Ibis. 150(1): 160–171. Close ); highly synchronized egg-laying frequently starting c. 18–23 Nov and lasting 10–18 days, median hatching date 12 Jan, with 82% of eggs hatching 11–14 Jan at Svarthamaren colony (mean date 9 Jan on Hop I) (20 Norman, F.I., Whitehead, M.D., Ward, S.J. and Arnould, J.P.Y. (1992). Aspects of the breeding biology of Antarctic Petrels and Southern Fulmars in the Rauer Group, East Antarctica. Emu. 92(4): 193–206. Close , 21 Norman, F.I. and Ward, S.J. (1999). Aspects of the ecology of South Polar Skuas Catharacta maccormicki at Hop Island, Rauer Group, East Antarctica. Emu. 99(3): 176–190. Close ), and most chicks fledging and adults departing in late Feb/early Mar (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 19 Creuwels, J.C.S., van Franeker, J.A., Doust, S.J., Beinssen, A., Harding, B. and Hentschel, O. (2008). Breeding strategies of Antarctic Petrels Thalassoica antarctica and Southern Fulmars Fulmarus glacialoides in the high Antarctic and implications for reproductive success. Ibis. 150(1): 160–171. Close ). Studies in E Antarctica suggest that this species, in common with other Antarctic birds, is starting to arrive at its colonies and breed later over the last half-century, which appears counter-intuitive given trends in global climate change (22 Barbraud, C. and Weimerskirch, H. (2006). Antarctic birds breed later in response to climate change. Proceedings of the National Academy of Sciences of the United States of America. 103(16): 6248–6251. Close ). Considered to be monogamous, with long-term pair-bonds (1 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ), but extra-pair copulations known; three of 41 chicks were fathered by different male, one of which was being raised by a female-female pair (23 Lorentsen, S.-H., Amundsen, T., Anthonisen, K. and Lifjeld, J.T. (2000). Molecular evidence for extrapair paternity and female-female pairs in AntarcticPetrels. Auk. 117(4): 1042–1047. Close ). Diurnal at breeding sites (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Forms colonies ranging in size from c. 100 pairs to over 1,000,000 birds, but numbers breeding at any given colony can fluctuate fourfold between years (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), with nests sometimes < 1 m apart (4 Bassett, J.A., Woehler, E.J., Ensor, P.H., Kerry, K.R. and Johnstone, G.W. (1990). Adélie Penguins and Antarctic Petrels at Mount Biscoe, Western Enderby Land, Antarctica. Emu. 98(1): 58–60. Close ); nests on cliff ledges or in hollows, on fairly level to sloping ground, with nests sparsely lined with small pebbles, bones, feathers, etc (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Single white egg, mean size 69·4 mm × 47·4 mm (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); incubation 40–49 days, in c. 5–6 shifts, first by female (19 Creuwels, J.C.S., van Franeker, J.A., Doust, S.J., Beinssen, A., Harding, B. and Hentschel, O. (2008). Breeding strategies of Antarctic Petrels Thalassoica antarctica and Southern Fulmars Fulmarus glacialoides in the high Antarctic and implications for reproductive success. Ibis. 150(1): 160–171. Close ), with shift length declining markedly over this period from mean c. 16 days at start to five days just before hatching (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), and males taking greater share of incubation than females (24 Lorentsen, S.-H. and Røv, N. (1995). Incubation and brooding performance of the Antarctic Petrel Thalassoica antarctica at Svarthamaren, Dronning Maud Land. Ibis. 137(3): 345–351. Close ); chicks have pale grey down  , whiter on head  and neck, hatch weight c. 56–65 g (25 Amundsen, T., Lorentsen, S.-H. and Tveraa, T. (1996). Effects of egg size and parental quality on early nestling growth: an experiment with the Antarctic petrel. Journal of Animal Ecology. 65: 545–555. Close ), brooded for c. 9–21 days (19 Creuwels, J.C.S., van Franeker, J.A., Doust, S.J., Beinssen, A., Harding, B. and Hentschel, O. (2008). Breeding strategies of Antarctic Petrels Thalassoica antarctica and Southern Fulmars Fulmarus glacialoides in the high Antarctic and implications for reproductive success. Ibis. 150(1): 160–171. Close ), then fed every 25–26 hours (26 Creuwels, J.C.S., Engelhard, G.H., van Franeker, J.A., van der Veer, W., Hasperhoven, J.G. and Ruiterman, W. (2010). Foraging strategies of Antarctic fulmarine petrels. Marine Orn.. 38(1): 17–22. Close ), with mean meal size of 146–151 g (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 26 Creuwels, J.C.S., Engelhard, G.H., van Franeker, J.A., van der Veer, W., Hasperhoven, J.G. and Ruiterman, W. (2010). Foraging strategies of Antarctic fulmarine petrels. Marine Orn.. 38(1): 17–22. Close ); fledging 42–47 days when 700 g (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Adults, chicks and eggs are predated by South Polar Skuas (Catharacta maccormicki) (20 Norman, F.I., Whitehead, M.D., Ward, S.J. and Arnould, J.P.Y. (1992). Aspects of the breeding biology of Antarctic Petrels and Southern Fulmars in the Rauer Group, East Antarctica. Emu. 92(4): 193–206. Close , 21 Norman, F.I. and Ward, S.J. (1999). Aspects of the ecology of South Polar Skuas Catharacta maccormicki at Hop Island, Rauer Group, East Antarctica. Emu. 99(3): 176–190. Close ), while egg desertion can be caused by incubating bird losing too much weight (24 Lorentsen, S.-H. and Røv, N. (1995). Incubation and brooding performance of the Antarctic Petrel Thalassoica antarctica at Svarthamaren, Dronning Maud Land. Ibis. 137(3): 345–351. Close ). Nesting success poorly known, but 63% of eggs survived at least 37 days while hatching success was 81% in another study (25 Amundsen, T., Lorentsen, S.-H. and Tveraa, T. (1996). Effects of egg size and parental quality on early nestling growth: an experiment with the Antarctic petrel. Journal of Animal Ecology. 65: 545–555. Close ), with mean overall breeding success estimated at c. 60% on Prydz Bay islands (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); on Ardery I, E Antarctica, over three years, mean hatching success was 53·3%, varying from c. 7% in 1996 to > 83% in 1998, while mean fledging success was 68·5%, range 50–69·2%, and mean overall breeding success was 36·5%, varying between 3·4% and 57·4% (19 Creuwels, J.C.S., van Franeker, J.A., Doust, S.J., Beinssen, A., Harding, B. and Hentschel, O. (2008). Breeding strategies of Antarctic Petrels Thalassoica antarctica and Southern Fulmars Fulmarus glacialoides in the high Antarctic and implications for reproductive success. Ibis. 150(1): 160–171. Close ). Hatching success is positively related to egg size (25 Amundsen, T., Lorentsen, S.-H. and Tveraa, T. (1996). Effects of egg size and parental quality on early nestling growth: an experiment with the Antarctic petrel. Journal of Animal Ecology. 65: 545–555. Close ), while chick growth is positively correlated to male body condition and average body condition of the pair (as such birds provide larger meals to their chicks) (27 Lorentsen, S.-H. (1996). Regulation of food provisioning in the Antarctic petrel Thalassoica antarctica. Journal of Animal Ecology. 65: 381–388. Close , 28 Tveraa, T., Sæther, B.-E., Aanes, R. and Erikstad, K.E. (1998). Regulation of food provisioning in the Antarctic petrel; the importance of parental body condition and chick body mass. Journal of Animal Ecology. 67: 699–704. Close ), and overall reproductive success is influenced by stochastic variation in the environment, probably related to climatic conditions (29 Sæther, B.-E., Lorentsen, S.-H., Tveraa, T., Andersen, R. and Pedersen, H.C. (1997). Size-dependent variation in reproductive success of a long-lived seabird, the Antarctic Petrel (Thalassoica antarctica). Auk. 114(3): 333–340. Close ). Annual adult survival estimated at 96%, and frequency of breeding at 47% (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ).

Not globally threatened (Least Concern). Thirty-five breeding colonies known, of which largest-known colony is that at Svarthamen, Dronning Maud Land, where between 55,000 and 205,000 pairs nest each year (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), although others may await discovery (30 Wilson, K.-J. and Harper, P.C. (1996). Birds observed at Scott Island, Ross Sea, Antarctica. Marine Orn.. 24(1): 51–52. Close , 31 Johansson, P. and Thor, G. (2004). Observations on the birds of the Vestfjella and Heimefrontfjella, Dronning Maud Land, Antarctica, 1991/92 and 21181181/1182. Marine Orn.. 32(1): 43–46. Close ). Total population may number several million birds, though considerable disagreement, especially between at-sea data and counts at breeding sites (2 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), with estimates of 1,200,000 birds and just 380,000 breeding pairs (of which > 170,000 pairs in Australian Antarctic territory) (32 Baker, G. B., R. Gales, S. Hamilton, and V. Wilkinson (2002). Albatrosses and petrels in Australia: a review of their conservation and management. Emu 102(1):71–97. Close ); in contrast, estimated 1,500,000–2,500,000 pairs in Prydz Bay area, and estimated 3,900,000 pairs in Ross Sea sector (late 1970s). Local declines at colonies have been reported (33 SCAR Bird Biology Subcommittee (1993). Scientific Committee on Antarctic Research Working Group on Biology Bird Biology Subcommittee Minutes of Meeting, 7-8 June 1992, Bariloche, Argentina. Marine Orn.. 21(1): 79–104. Close ), although these might reflect ‘natural’ fluctuations in numbers (see Breeding). Restriction to bleak, icy habitat and breeding on mountains far inland imply few adverse factors, apart from rigors of climate. Could be affected by development of krill fisheries, as breeding success known to be related to levels of euphausiid and fish abundance.