White-bellied sea-eagle

Description

The white-bellied sea eagle (Haliaeetus leucogaster),also known as the white-breasted sea eagle,is a large diurnal bird of prey in the family Accipitridae.Originally described by Johann Friedrich Gmelin in 1788,it is closely related to Sanford's sea eagle of the Solomon Islands,and the two are considered a superspecies.A distinctive bird,the adult white-bellied sea eagle has a white head,breast,under-wing coverts and tail.The upper parts are grey and the black under-wing flight feathers contrast with the white coverts.The tail is short and wedge-shaped as in all Haliaeetus species.Like many raptors,the female is slightly larger than the male,and can measure up to 90 cm (35 in) long with a wingspan of up to 2.2 m (7.2 ft),and weigh 4.5 kg (9.9 lb).Immature birds have brown plumage,which is gradually replaced by white until the age of five or six years.The call is a loud goose-like honking.The white-bellied sea eagle has a white head,rump and underparts,and dark or slate-grey back and wings.In flight,the black flight feathers on the wings are easily seen when the bird is viewed from below.The large,hooked bill is a leaden blue-grey with a darker tip,and the irides are dark brown.The cere is also lead grey.The legs and feet are yellow or grey,with long black talons (claws).Unlike those of eagles of the genus Aquila,the legs are not feathered.The sexes are similar.Males are 66–80 cm (26–31 in) long and weigh 1.8–3 kg (4.0–6.6 lb).Females are slightly larger,at 80–90 cm (31–35 in) and 2.5–4.5 kg (5.5–9.9 lb).The wingspan ranges from 1.78 to 2.2 m (5.8 to 7.2 ft).A 2004 study on 37 birds from Australia and Papua New Guinea (3 °S to 50 °S) found that birds could be sexed reliably on size,and that birds from latitudes further south were larger than those from the north.There is no seasonal variation in plumage.The moulting pattern of the white-bellied sea eagle is poorly known.It appears to take longer than a year to complete,and can be interrupted and later resumed from the point of interruption.The wings are modified when gliding so that they rise from the body at an angle,but are closer to horizontal further along the wingspan.In silhouette,the comparatively long neck,head and beak stick out from the front almost as far as the tail does behind.For active flight,the white-bellied sea eagle alternates strong deep wing-beats with short periods of gliding.The wings are modified when gliding so that they rise from the body at an angle,but are closer to horizontal further along the wingspan.In silhouette,the comparatively long neck,head and beak stick out from the front almost as far as the tail does behind.For active flight,the white-bellied sea eagle alternates strong deep wing-beats with short periods of gliding.A young white-bellied sea eagle in its first year is predominantly brown,with pale cream-streaked plumage on their head,neck,nape and rump areas.The plumage becomes more infiltrated with white until it acquires the complete adult plumage by the fourth or fifth year.The species breeds from around six years of age onwards.The lifespan is thought to be around 30 years.The loud goose-like honking call is a familiar sound,particularly during the breeding season;pairs often honk in unison,and often carry on for some time when perched.The male's call is higher-pitched and more rapid than that of the female.Australian naturalist David Fleay observed that the call is among the loudest and furthest-carrying of all Australian bird calls,in stark contrast to the relatively quiet calls of the wedge-tailed eagle.