a.k.a. Grey-headed Mollymawk
- Thalassarche chrysostoma
Identification
Similar to other mollymawks and confusable with several other species. Adult: mantle dark blue-grey, more blackish on back, upperwings blackish-brown, rump white, tail dark grey and underparts white. Head blue-grey, paler on forehead and crown with dark brow and white crescent under eye. Underwing white with dark tip and irregular dark margins broadest on leading edge. Iris brown, bill black with bright yellow upper and lower ridges and pinkish-red to orange tip. Immature: juvenile has blackish-grey bill and darker grey head and underwing almost all grey. Subadults have dark bill with yellow tip, head closer to adult and more white on underwing. Grey head, bill colour and underwing pattern distinguish adult from Black-browed Albatross D. melanophris, the most similar species. Juvenile has the darkest underwing of any southern Diomedea and separated from juvenile Black-browed by blackish bill and darker collar.
Length 81-91cm. Wingspan 215-220cm.
VOICE Various braying, grunting and cackling calls.
Distribution
Circumpolar in Southern Oceans. Breeds on Diego Ramirez off Cape Horn, on South Georgia and on Marion, Prince Edward, Crozet, Macquarie, Kerguelen and Campbell Islands. Prefers colder waters and disperses throughout the Southern Oceans mainly south of 350S but occurs north to 150S off Peru in the Humboldt Current. Uncommon but regular off eastern South Africa and in Australia occurs May to November off southern and western coasts and common off eastern Tasmania.
Vagrants reported from the North Atlantic but none are currently accepted and also reported from the Pacific coast of Panama.
Taxonomy
Diomedea vs. Thalassarche Genera Phoebastria and Thalassarche formerly placed in the Diomedea, but now considered by virtually all authorities (Clements, Howard & Moore, AOU, BOU, SACC) to be separate genera in light of Nunn et al. (1996) and Penhallurick & Wink (2004).
Habitat
At breeding sites from August until May, otherwise at sea, rarely follows ships.
Behaviour
BREEDING Nest is a large bowl made of mud and vegetable matter. One egg, white with pinkish-brown band at larger end (107 x 67mm). Incubated by both parents for about 55-60 days and young fed by both parents. Fledges after five months.
DIET Squid and fish, sometimes refuse from ships.
