Short-tailed Albatross
| Short-tailed Albatross | |
|---|---|
 | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Procellariiformes |
| Family: | Diomedeidae |
| Genus: | Phoebastria |
| Species: | P. albatrus |
| Binomial name | |
| Phoebastria albatrus (Pallas, 1769) | |
| Synonyms | |
Diomedea albatrus
| |
The Short-tailed Albatross or Steller's Albatross, Phoebastria albatrus, is a large rare seabird from the North Pacific. Although related to the other North Pacific albatrosses, it also exhibits behavioural and morphological links to the albatrosses of the Southern Ocean. It was described by the German naturalist Peter Simon Pallasfrom skins collected by the Georg Wilhelm Steller (after whom its other common name is derived). Once common, it was brought to the edge of extinction by the trade in feathers, but with protection has recently made a recovery.
Taxonomy
Short-tailed Albatrosses are a type of Albatross that belong to Diomedeidae family and come from the Procellariiformes order, along with Shearwaters, Fulmars, Storm-petrels, and Diving-petrels. They share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns. Although the nostrils on the Albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between 7 and 9 horny plates. Finally, they produce a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus. This is used against predators as well as an energy rich food source for chicks and for the adults during their long flights. They also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, due to the high amount of ocean water that they imbibe. It excretes a high saline solution from their nose. Going back in time, fossils of albatrosses from the mid-Pleistocene inBermuda and North Carolina are considered to be closest to the Short-tailed Albatross.
Description
The Short-tailed Albatross is a medium sized albatross, with a wingspan of 215–230 cm (85–91 in), a length of 84–94 cm (33–37 in) and a body weight that can be 4.3–8.5 kg (9.5–19 lb). Its plumage as an adult is overall white with black flight feathers, some coverts, as well as a black terminal bar on its tail. It has a yellow-stained nape and crown. Its billis large and pink; however, older birds will gain a blue tip. The juveniles are an all-over brown colour, and they will whiten as they mature,in about 10 to 20 years. It can be distinguished from the other two species of albatross in its range, the Laysan Albatross and the Black-footed Albatross by its larger size and its pink bill (with a bluish tip), as well as details of its plumage. Contrary to its name its tail is no shorter than that of the Laysan or Black-footed, and is actually longer than that of the other member of the genus Phoebastria, the Waved Albatross.
Range and habitat
Short-tailed Albatrosses now nest on four islands, with the majority of birds nesting on Torishima, and almost all of the rest on Minami-kojima in the Senkaku Islands. A female-female pair began nesting on Kure in the late 2000s, but to date they have not produced a viable egg. A chick hatched on 14 January 2011 on Midway. Both Midway and Kure are in the Northwestern Hawaiian Islands. During non-breeding season they range across the North Pacific, with the males and juveniles gathering in the Bering Sea, and the females feeding off the coast of Japan and easternRussia. They can also be found as far east as California. In fact, the Short-tailed Albatross is seen on a number of the United States' state endangered species lists including Washington State.
The species has been extirpated as a breeder from Kita-no-shima, Enewetak Atoll, Kobishi, and theBonin Islands (Nishino Shima, Yomejima, and Mukojima).
Behavior
Feeding
Reproduction
This albatross historically preferred to nest on large open areas near stands of the grass, Miscanthus sinensis.
Conservation
| Breeding Location | Breeding Pair | Trend |
|---|---|---|
| Torishima | 1,922 adults | up from 25 since 1954 |
| Minami-kojima | 442 | Unknown |
| Total | 2,364 | 79% increase over 76 years |
The IUCN classifies this species as vulnerable, with an occurrence range of 34,800,000 km2 (13,400,000 sq mi) and a breeding range of 9 km2 (3.5 sq mi).
The Short-tailed Albatross came perilously close to extinction. They were hunted on an almost industrial scale for their feathers in the later half of the 19th century, with some estimates claiming upward of 10 million birds hunted. By the 1930s the only population left was on Torishima, between 1927 and until 1933 hunting continued when the Japanese governmentdeclared the ban of hunting to save the species, after which the albatrosses stopped breeding on the island. At this point the species was assumed to be extinct and research became impossible with the outbreak of World War II. On 1949 an American researcher arriving on this island declared the species to be extinct, but an estimated 50 individuals, most likely juveniles, survived at sea (all albatross species take a long time to reach sexual maturity and will not return to their natal colony for many years). After the return of the birds they were more carefully protected, and the first egg was laid by the returning birds in 1954. Varieties of albatross decoys were placed around on the island after it was discovered that like other albatross species, this species also were enticed to breed if placed in a group.
Today, longline fisheries, and volcanic eruptions on Torishima are the largest threats; however, introduced predators, environmental contaminants, soil instability, and extreme weather are also threats.
There are many measures underway to protect this species. Japan, Canada, and the USA list this bird as a protected species. Torishima is a National Wildlife Protection Area, and native plant species are being transplanted to assist in nesting. Also, most commercial longline fisheries use bycatch mitigation devices.
No comments:
Post a Comment