Members of the genus Haliaeetus are large to very large eagles, with long, broad wings and medium to short rounded or wedge-shaped tails. The bill is large, strong and compressed. The legs are short and the toes and talons powerfully developed
Immatures are entirely brown above, the feathers fringed paler, with white on the inner webs of the secondary flight feathers. The tail is dark brown, mottled white towards the base. The throat is fulvous with darker central streaks. The rest of the underside is darker brown, the feathers often tipped paler. The eyes are brown; the cere grey, legs off-white. Tail of immatures may be longer than in adult. Most easily confused with the Golden Eagle (Aquila chrysaetos), which is about the same size. At rest, in adult plumage, the golden-brown head and neck forming a cape extending on to the back and contrasting with the dull brown upper parts, together with the white band on the brown tail are distinctive. In flight it is slimmer and lighter-looking than the Golden Eagle, possibly more like a kite. Adults with white tail bases are paler overall than immature Golden Eagles. Immatures are distinguished from those of the Golden, White-tailed and Bald Eagles (with which it scarcely comes in contact except at the eastern end of the range) by its all-dark tail without the pale base; they are not so dark as young Golden Eagles. In all plumages the bare tarsus distinguishes it from the Golden Eagle. The species is much smaller than the White-tailed Eagle, and has a weaker, dark-coloured bill.
Listen to the sound of Pallass Sea-Eagle
Copyright remark: Most sounds derived from xeno-canto
Between two and four eggs are laid at intervals of two days. They are white, rather coarse and glossless. Incubation begins with the first egg and is mostly the responsibility of the female, though the male does take a small share. Food is brought to the nest by the male during the incubation period and he often perches nearby for long periods. The incubation period of is about 40 days.
When the young first hatch, they are tended by the female. In the early stages the male usually catches prey, while the female remains on the nest and feeds the young; later the female takes a share and the male also helps in feeding the young. The fledging period is about 70-105 days, the latter in north India making, with the 40 days incubation period, a total breeding period of about 140-150 days. Birds breeding further north could not take this long to rear their young, and young are fledged in Turkestan by early July from eggs laid in late March, a combined period of about 100 days. Young from clutches laid in May in Tibet must be able to migrate within a month or so of leaving the nest in late August to September.
Video Pallass Sea-Eagle
copyright: J. del Hoyo
The extralimital range of the species lies in Kazakhstan, Tajikistan, Uzbekistan, Iran and Afghanistan, the last two of which it visits as a non-breeding visitor (to the Seistan swamps, south Caspian Sea and the Persian Gulf). Breeding has not been confirmed in Tajikistan, but passage and non-breeding visitors occur at water bodies in the south of the country and the Pamis mountains. Similarly, no nests are known in Uzbekistan, but breeding is considered probable on the eastern Aral Sea and in the Amudar’ya valley where there are (or were until recently) frequent sightings, although some of these probably refer to non-breeders or birds moving north after breeding in India. In Turkmenistan, too, records are considered to relate to dispersing non-breeders. In Kazakhstan Pallas’s Fish-eagle formerly summered regularly and in some numbers in the Volga_Ural steppes and it is generally more regular in the west of the country, over half of c.50 records during 1970_1995, including five in the breeding season, coming from the area between the Volga, Ural and Emba rivers.
There are further widespread reports of birds in summer from the north of the country (e.g. Turgay depression, Kurgal’dzhino) as well as the south and south-east. One was collected in the southern Altay in 1966, but none there in the period 1978_1986. There are few breeding records in Kazakhstan, where the range apparently once extended from the north-east shores of the Caspian Sea (last bred 1947) east to the Aral Sea, Syrdar’ya river and Balkhash lake_Ili river area. A nest was found even further east at Lake Markakol’ (Altay) in 1876. After dramatic declines in these areas, observations suggested breeding may have taken place on or near the Ili river in the 1980s: in the Ili valley close to the Malaysary mountains, two adults were recorded in May 1985, single birds in June 1985 and May 1986; some 100 km further east in the valley (near the Kalkany mountains), single birds were seen in July and August, and two displaying birds in August 1989. Stragglers have occurred elsewhere from Ukraine, Crimea, and the Sea of Azov to eastern Caucasus, but it is now only an accidental visitor to these regions. Similarly, it was once a regular winter visitor to Iraq in small numbers, but this no longer appears to be the case. It has occurred further west into several European countries as a vagrant, although there appear to be no recent records. The population is likely to be <10,000 mature individuals.
Autumn dispersal USSR begins October in central Kazakhstan. Spring return to some extent dependent on thawing of rivers; reappears Syr-Dar’ya river in February and begins breeding there March, but northward movement continues April-May and these presumed immatures. In the warmer parts of its range, such as in north India and north Burma, it is resident, but on the high Asian plateau and in Central Asian steppes it is a migrant, departing in September-October and returning late in the year, March to mid-May, to breed. On migration it travels in small groups of five to seven individuals, but may collect in larger numbers in favourable feeding places. It is more gregarious than most of the genus, and it is only in winter that it is likely to appear on any sea coast, and then only on the landlocked Black and Caspian Seas.