Friday, Nov 21, 2014

Albatrosses

Indian Yellow-nosed Albatross, Thalassarche carteri


Amsterdam Albatross or Amsterdam Island Albatross, Diomedea amsterdamensis Albatrosses are large web-footed seabirds that range widely in the Southern Ocean and the North Pacific.

Albatrosses

In the North Pacific, they were once known as Goonie birds or Gooney birds. In the southern hemisphere, they are often referred to as mollymawk.

Albatrosses are long lived with a life expectancy of 50 or longer. The oldest recorded was a Northern Royal Albatross that was ringed as an adult and lived for another 51 years. Its age at death was estimated to be 61.


Buller's Albatross or Buller's Mollymawk, Thalassarche bulleri Description

They are amongst the largest of flying birds. The great albatrosses (Diomedea) specifically have the largest wingspans of any extant birds exceeding 340 cm (11 ft) - but the other species' wingspans are considerably smaller at 1.75 m (5.7 ft). The long, slender wings are stiff and cambered, with thickened streamlined leading edges.

They have large heads with massive hooked bills that are strong and sharp-edged. The beak is composed of several horny plates. Along the sides are the two "tubes" (long nostrils), which allow the albatrosses to have an acute sense of smell.

The feet have no hind toe and the three anterior toes are webbed.

Their bodies are mainly white with some variation of dark upper-wing and back, white undersides. Although the Southern Royal Albatross is almost completely white except for the ends and trailing edges of the wings in fully mature males.

Albatrosses are highly efficient flyers - using dynamic soaring and slope soaring to cover great distances and they can remain aloft for several hours.


Short-tailed Albatross or Steller's Albatross, Phoebastria albatrus Species

 Laysan Albatross feeding its chick

Black-footed Albatross, Phoebastria nigripes Breeding and Courtship Behavior

Albatrosses usually nest in colonies on isolated islands. Albatrosses reach sexual maturity when they are about five years old, although some species may not start breeding until they are 10.

Their courting behavior involves preening, pointing, calling, bill clacking and staring. When birds return to their colonies, they may perform a dance with many partners, until one partner is chosen. They then continue to perfect an individual language that will eventually be unique to that one pair. Once they have established a pair bond, they may never dance again. Even though these relationships are typically for life, "divorces" may occur - particularly after several years of breeding failure.

The Albatross female only lays one subelliptical white egg that is covered with reddish brown spots. The eggs weigh from 200–510 g (7.1–18 oz).

Incubation lasts around 70 to 80 days - which is the longest incubation period of any bird.

The newly-hatched chicks are semi-altricial that requires brooding and frequent feedings by their parents. They are fed fresh squid, fish, krill and stomach oil.

Albatross chicks develop slowly. The chicks of larger species fledge 280 days after hatching,, while the chicks of the smaller species fledge when they are 140 and 170 days old.

Black-browed Albatross (Thalassarche melanophrys) - Nesting Colony


Laysan Albatross died from ingestnig plastic garbageStatus

21 species of albatrosses are recognized by the IUCN - 19 of which are threatened with extinction. Their numbers have declined in the past due to harvesting for feathers. But they are also threatened by introduced species, such as rats and cats that take the eggs and prey on the chicks and nesting adults.

Another big problem is pollution and the decline in fish stocks due to overfishing. Many of them are killed in long-line fisheries - as they are attracted to the bait and get hooked on the lines.

Ingestion of plastic flotsam is another danger that they faces. The amount of plastic in the seas has increased dramatically since the first record in the 1960s, coming from waste discarded by ships, offshore dumping, litter on beaches and waste washed to sea by rivers. Studies have shown that ingestion of plastics results in declining body weight and body condition. This plastic is also regurgitated and fed to chicks. A study of Laysan Albatross chicks showed large amounts of ingested plastic iny dead chicks.


Diet / Feeding

They feed on squid, fish and krill by either scavenging, surface seizing or diving.

Wandering Albatross, Snowy Albatross, or White-winged Albatross, Diomedea exulansSooty Albatross or Dark-mantled Sooty Albatross Waved Albatross, Phoebastria irrorata - also known as Galapagos Albatross Southern Royal Albatross, Diomedea epomophora hybrid albatross Southern Royal Albatross, Diomedea epomophoraAmsterdam Albatross adult in flight, showing dark plumage typical of the species

Species Research by Sibylle Johnson

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