Short-tailed Albatross (Phoebastria albatrus)

Short-tailed Albatross

Subspecies

Monotypic species

Genus

Albatrosses are the ‘largest’ birds in terms of wingspan. Royal Abatrosses, for instance, may reach a wing span of almost 3.5m, which make them look like feathered sail plaines. They are also the largest members of the tubenose family. Only the smallest albatross species are equalled in size by the Giant Petrels (Macronectes). Albatrosses occur in all oceans, except the northern part of the Atlantic. In ancient times they were also present in that part of the world, but nowadays only an occasional straggler find its way to the North Atlantic. Most of the 24 species are Southern Hemisphere breeders, only three actually breed north of the Equator in the Pacific Ocean.
Albatross taxonomy is subject of discussion for a long time, and has been at times rather chaotic. Based on external characters: plumage patterns, tail shapes, bill structure (size, organization of the plates and coloration) albatrosses were, until recently, divided in 13-14 species in four ‘natural groups’: the Great Albatrosses, the Mollymawks, the North Pacific Albatrosses, grouped in the genus Diomedea and the Sooty Albatrosses Phoebastria. More recently DNA-analyses supports the division in four distinct groups but the were elevated to a generic status and has led to a splitting into 24 species: Great Albatrosses Diomedea (7 species), the Northern (Pacific) Albatrosses Phoebastria (4 species), the southern Mollymawks Thalassarche (11 species) and the Sooty Albatrosses Phoebetria (2 species). Recently this taxonomy is challenged by who proposed to lump some of the ‘species’ again based on their molecular analysis. Since then the discussion flared up and has not ended yet. Some list six species of Great Albatrosses, including two subspecies of Antipodian Albatross.

Physical charateristics

Medium-sized albatross. Adult has white head and body and golden cast to crown and nape. White tail with black terminal bar. White upperwing with black flight feathers and some coverts. White underwing with black margins, some grey-brown axillaries and coverts. Juvenile is blackish-brown with flesh-coloured legs. Immatures progressively whiten with age. All ages, large pink bill, bluer at tip with age.

wingspan min.:	190	cm	wingspan max.:	210	cm
size min.:	89	cm	size max.:	91	cm
incubation min.:	64	days	incubation max.:	65	days
fledging min.:	140	days	fledging max.:	150	days
broods:	1		eggs min.:	1
			eggs max.:	1

Range

Pacific Ocean : North, Central. Phoebastria albatrus breeds on Torishima (Japan), and Minami-kojima (Senkaku Islands), that are claimed jointly by Japan, mainland China and Chinese Taipei. Historically there are believed to have been at least nine colonies south of Japan and in the East China Sea. Its marine range covers most of the northern Pacific Ocean, but it occurs in highest densities in areas of upwelling along shelf waters of the Pacific Rim, particularly along the coasts of Japan, eastern Russia, the Aleutians and Alaska. During breeding (December – May) it is found in highest densities around Japan. Satellite tracking has indicated that during the Pacific Oceanst-breeding period, females spend more time offshore of Japan and Russia, while males and juveniles spend greater time around the Aleutian Islands, Bering Sea and off the coast of North America

Habitat

it prefers level, open, areas adjacent to tall clumps of the grass Miscanthus sinensis for nesting

Reproduction

Phoebastria albatrus is a colonial, annually breeding species, with each breeding cycle lasting about 8 months. Birds begin to arrive at the main colony on Torishima Island in early October. A single egg is laid in late October to late November and incubation lasts 64 to 65 days. Hatching occurs in late December through January. Chicks begin to fledge in late May into June. There is little information on timing of breeding on Minami-kojima. First breeding sometimes occurs when birds are five years old, but more commonly when birds are aged six. Both parents feed the
chick, often by regurgitating (vomiting) partially digested food directly into its beak. The young albatross leaves the nest at about five months of age but does not reach full maturity for eight to nine years. Short-tailed albatrosses mate for life. The couples return to the same nest sites year after year.

Feeding habits

It forages diurnally and potentially nocturnally, either singly or in groups primarily taking prey by surface-seizing. It feeds mainly on squid, but also takes shrimp, fish, flying fish eggs and other crustaceans

Video Short-tailed Albatross

httpv://www.youtube.com/watch?v=4viHuO3KIKc

Conservation

This species is listed as Vulnerable because, although conservation efforts have resulted in a steady population increase, it still has a very small breeding range, limited to Torishima and Minami-kojima (Senkaku Islands), rendering it susceptible to stochastic events and human impacts.
Its historical decline was caused by exploitation. Today, the key threats are the instability of soil on its main breeding site (Torishima), the threat of mortality and habitat loss from the active volcano on Torishima, and mortality caused by fisheries. Torishima is also vulnerable to other natural disasters, such as typhoons. Introduced predators are a potential threat at colonies. Environmental contaminants at sea (oil based compounds) may also be a threat

Short-tailed Albatross status Vulnerable

Migration

Present movements unknown, probably still disperses widely in N Pacific, reaching the Gulf of Alaska and W coast of N America, as in past; 3 recent records from Hawaii, including a ringed adult that has visited Midway I regularly since 1972.

Distribution map

Short-tailed Albatross distribution range map

Planet of Birds