Thursday 10 November 2011

Haliaeetus pelagicus Steller

Haliaeetus pelagicus Steller

Flying Animal | Haliaeetus pelagicus Steller | Steller's sea eagle (Haliaeetus pelagicus) is one of the largest of the sea and fish eagles of the genus Haliaeetus .These large blackish-brown birds have an enormous, strongly arched yellow bill . The feathers on the shoulders, tail and legs are white , and females are generally the larger sex .The relationships of Steller's Sea-eagle are not completely resolved. mtDNA cytochrome b sequence data tentatively suggests that this species's ancestors diverged early in the colonization of the Holarctic by sea eagles. This is strongly supported by morphological traits such as the yellow eyes, beak, and talons shared by this species and the other northern sea-eagles, the White-tailed and Bald Eagles, and biogeography. It is unique among all sea eagles in having a yellow bill even in juvenile birds, and possessing 14, not 12, rectrices. The skull (at about 14.6 cm (5.7 in)) and bill are the largest of any eagle and comparable in size to the largest Old World vultures, the biggest accipitrids.
Habitat – Steller's sea eagle

Inhabits coastal cliffs and estuaries; further inland, Steller's eagles are associated with river and lakeshore forests.

Haliaeetus pelagicus Steller

Reproduction
This eagle builds several aeries (height, 150 cm; diameter up to 250 cm) high up on trees and rock. It is possible that the eagles change occasionally between these nests.

After courtship, which usually occurs between February and March, the animals lay their first white-green eggs around April to May. Usually only one chick survives. After an incubation period of around 39 – 45 days the chicks hatch, having ash grey to white down. As young birds the down changes to brown feathers and at an age of around ten weeks, the young birds learn to fly. They reach sexual maturity at around four to five years. Full adult plumage in the Steller's Sea Eagle only appears at age eight to ten years.

Eggs and nestlings can be preyed on by arboreal mammals, such as martens, and birds, usually corvids. In one case, a brown bear was able to access a nest and ate the nestlings contained in it. Once fully grown, the eagle has no natural predators.

Haliaeetus pelagicus Steller

Biology – Steller's sea eagle
Steller's sea eagles start to build their large, bulky nests in the trees in late February and early March. The first eggs are laid in mid-April, and clutch size varies from one to three eggs; hatchlings emerge in mid-May to mid-June and begin to fly by August and early September. These large birds feed predominately on salmon (Onchorhynchus spp.), which are taken both dead and alive. Prey is usually caught by swooping from perches located at the waters' edge, or from circling and diving down; occasionally birds will stand in the shallows to catch fish. Steller's sea eagles have a large, powerful bill that is perfectly adapted to ripping and tearing at flesh and these birds will also prey on other fish and the carcasses of animals such as seals and sea lions . Where there are large congregations of prey such as salmon, groups of eagles will gather and individuals will often attempt to steal food from each other in a behaviour known as 'kleptoparasitism. and very amazing bird.

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