Name : Titan

Sex : Male

Species : Steller's Sea Eagle - Haliaeetus pelagicus

Hatch Date : 06-04-2017



Steller's sea eagle (Haliaeetus pelagicus) is a large diurnal bird of prey in the family Accipitridae. It was originally described by Peter Simon Pallas in 1811. No subspecies are recognised. A sturdy eagle, it has dark brown plumage with white wings and tail, and yellow beak and talons. On average, it is the heaviest eagle in the world, at about 5 to 9 kg (11 to 20 lb), but may be below the harpy eagle (Harpia harpyja) and Philippine eagle (Pithecophaga jefferyi) in some standard measurements.

It lives in coastal northeastern Asia and mainly preys on fish and water birds. The Kamchatka Peninsula in Far Eastern Russia is known for its relatively large population of these birds. Around 4,000 of these eagles live there. Steller's sea eagle is listed as vulnerable on the International Union for Conservation of Nature (IUCN)'s Red List of Endangered species.

Steller's sea eagle is the largest bird in the genus Haliaeetus and is one of the largest raptors overall. Females vary in weight from 6,195 to 9,500 g (13.658 to 20.944 lb), while males being rather lighter with a weight range of 4,900 to 6,800 g (10.8 to 15.0 lb). The average weight is variable, possibly due to seasonal variation in food access or general condition of eagles, but has been reported as high as a mean mass of 7,757 g (17.101 lb) to a median estimate weight of 6,250 g (13.78 lb), excluding expired eagles that were poisoned by lead and endured precipitous weight loss by the occasion of their deaths. At its average weight, the Steller's seems to outweigh the average harpy by approximately 500 g (1.1 lb) and the average Philippine eagles by more than 1,000 g (2.2 lb). Steller's sea eagle can range in total length from 85 to 105 cm (2 ft 9 in to 3 ft 5 in), apparently males average about 89 cm (2 ft 11 in) in length, while females average about 100 cm (3 ft 3 in), marginally shorter on average than the harpy eagle and about 65 mm (2.6 in) shorter than the Philippine eagle. The wingspan is from 1.95 to 2.5 m (6 ft 5 in to 8 ft 2 in) and the wing chord measurement is 560 to 680 mm (22 to 27 in). The sea eagle's wingspan is one of the largest of any living eagle, at a median of 2.13 m (7 ft 0 in) per Ferguson-Lees (2001) or a median of 2.2 m (7 ft 3 in) per Saito (2009). The Steller's sea eagle's absolute maximum wingspan is less certain; many sources place it at up to 2.45 m (8 ft 2 in). However, less substantiated records indicate that it may also reach even greater wingspans. Three separate sources claim unverified Steller's sea eagles spanning up to 2.7 m (8 ft 10 in), 2.74 m (9 ft 0 in) and 2.8 m (9 ft 2 in), respectively. It is unique among all sea eagles in having a yellow bill even in juvenile birds, and possessing 14, not 12, rectrices.

The mature Steller's sea eagle has mostly dark brown to black plumage, with strongly contrasting white on the lesser and median upper-wing coverts, underwing coverts, thighs, under-tail coverts and tail. Their diamond-shaped, white tails are relatively longer than those of the white-tailed eagle. The bold, pied coloration of adults may play some part in social hierarchies with other eagles of their own species during the nonbreeding season, although this has not been extensively studied. The eyes, the bill, and the feet of adults are yellow.
The downy plumage of chicks is silky white on hatching, though it soon turns a smoky brown-grey. As in other sea eagles, remiges and rectrices of the first-year plumage are longer than those of adults. Juvenile plumage is largely a uniform dark brown with occasional grey-brown streaking about the head and the neck, white feather bases, and light mottling on the rectrices. The tail of the immature eagle is white with black mottling distally. The young Steller's sea eagle has a dark brown iris, whitish legs, and blackish-brown beak. Through at least three intermediate plumages, mottling in the tail decreases, body and wing feathering acquires a bronze cast, and the eye and bill lighten in colour. Definitive plumage is probably reached in the fifth year of life, based on fragmentary data from captives. First and intermediate plumages are difficult to distinguish from those of the white-tailed eagle, which co-occurs in the entire breeding range of the Steller's.

Steller's sea eagle is known to make a deep barking cry, ra-ra-ra-raurau, in aggressive interactions, its call similar to the white-tailed eagles but deeper. During the display at the beginning of the breeding season, they have been heard to make calls to each that sound like very loud, deep-voiced gulls.

Steller's sea eagle breeds on the Kamchatka Peninsula, the coastal area around the Sea of Okhotsk, the lower reaches of the Amur River and on northern Sakhalin and the Shantar Islands, Russia. The majority of birds winter south of their breeding range, in the southern Kuril Islands, Russia and Hokkaidō, Japan. The Steller's sea eagle is less prone to vagrancy than the white-tailed eagle, as it lacks the long-range dispersal typical of juveniles of that species, but vagrant eagles have been found in North America, at locations including the Pribilof Islands and Kodiak Island, and inland in Asia to as far as Beijing in China and Yakutsk in Russia's Sakha Republic, and south to as far as Taiwan.

The large body size (see also Bergmann's rule) and distribution of Steller's sea eagle suggests it is a glacial relict, meaning it evolved in a narrow subarctic zone of the northeasternmost Asian coasts, which shifted its latitude according to ice age cycles, and never occurred anywhere else. Nests are built on large rocky outcroppings or at the tops of large trees on the coast and alongside large rivers with mature trees. Habitat with large Erman's birches (Betula ermanii) and floodplain forests of larches, alders, willows and poplar are preferred. Some eagles, especially those that nest in sea coast, may not migrate. The timing, duration, and extent of migration depends on ice conditions and food availability. On Kamchatka, eagles overwinter in forests and river valleys near the coast, but are irregularly distributed over the peninsula. Most wintering birds there appear to be residential adults. Steller's sea eagles that do migrate fly down to winter in rivers and wetlands in Japan, but will occasionally move to mountainous inland areas as opposed to the sea coast. Each winter, drifting ice on the Sea of Okhotsk drives thousands of eagles south. Ice reaches Hokkaido in late January. Eagle numbers peak in the Nemuro Strait in late February. On Hokkaido, eagles concentrate in coastal areas and on lakes near the coast, along with substantial numbers of white-tailed eagles. Eagles depart between late March and late April, adults typically leaving before immatures. Migrants tend to follow sea coasts and are usually observed flying singly. In groups, migrants are typically observed flying 100–200 m (330–660 ft) apart. On Kamchatka, most migrants are birds in transitional plumages. They are also occasionally seen flying over the northern ocean or perching on sea ice during the winter.


CLICK HERE - To Return To Our Birds Page