THALASSOAETUS. 243 



3.65, middle toe 2.95-3.50. Nest on cliffs near sea-shore. Eggs 2-3, 3.00 

 X 2.30, plain dead white. Sab. Northern portions of eastern hemi- 

 sphere, and southeastern Greenland. 



351. H. albicilla (Linn.). Gray Sea Eagle. 



a . Adult with head and neck pure white, in abrupt contrast with color of body ; 

 tail-coverts also white. Young with plumage blackish, grayish brown, and 

 white, without cinnamon-brown or isabella-color. Adult: Head, neck,' tail- 

 coverts, and tail entirely white; rest of plumage dusky grayish brown, varying 

 to brownish black (the margins of the feathers usually paler). Immature (sec- 

 ond or third year) : Head and neck blackish, the lanceolate feathers of hind- 

 neck tipped with pale brownish, all the feathers pure white beneath surface ; 

 upper parts mixed grayish brown and blackish, usually with more or less 

 admixture of whitish ; tail blackish, the inner webs of feathers more or less 

 blotched or " spattered" with whitish ; lower parts mixed white and dusky, 

 either color predominating, according to the individual. Young, first year : 

 Whole plumage nearly uniform black, the feathers of lower parts, however, 

 with their bases white, this more or less concealed in places, producing a 

 somewhat spotted or blotched appearance. Downy young.- Uniform sooty 

 gray. Nest on tall trees, usually near lakes or rivers, sometimes on cliffs. 

 Male: Length 30.00-35.00, extent about 7 feet, wing 20.00-25.90, tail 11.00- 

 15.25, culmen 1.85-2.25, tarsus 2.65-3.40, middle toe 2.35-2.90, hind claw 

 1.68-1.90. Female: Length 34.00-43.00, extent about 7 to 8 feet, wing 

 23.50-28.00, tail 12.50-16.00, culmen 1.90-2.35, tarsus 3.25-3.70, middle toe 

 2.55-3.10, hind claw 1.60-2.00. Nest usually on large trees. Eggs 2-3, 2.90 

 X 2.27, plain white. Nab. Whole of North America, and across Aleutian 

 chain to Commander Islands, Kamtschatka. 



352. H. leucocephalus (Linn.). Bald Eagle. 



Genus THALASSOAETUS Kaup. 1 (Page 223, pi. LXXL, fig. 2.) 



Species. 

 Adult : General color dark grayish brown, the forehead, lesser and middle wing- 

 coverts, thighs, rump, tail-coverts, and tail, pure white ; lanceolate feathers of hind- 

 neck pale grayish brown, with lighter edges ; bill, cere, and feet intense yellow in 

 life ; iris pale yellow. Young : Entirely dusky brownish, or with more or less ad- 

 mixture of white, according to age, on those portions which are white in adult ; 

 bill more or less obscured with dusky. Male : Length 37.60-38.00, extent 87.50, 

 wing 23.25, tail 13.60 (graduated for 4.10), culmen 2.45. Female : Length about 

 41.00, extent 93.00, wing 24.00-26.00, tail 14.25, culmen 2.60-2.75, hind claw 1.95. 

 Downy young : Uniform smoky brownish gray. Nab. Sea-coasts and larger rivers 

 of Kamtschatka and borders of Okhotsk Sea, south, in winter, to Japan ; occasional 



or accidental in Aleutian Islands ? 



T. pelagicus (Pall.). Kamtschatkan Sea Eagle. 2 



1 Thalaeeoagtue Kaup, Class. S'aug. Viig. 1844, 123. Type, Aquila pelagica Pall. 



2 Aquila pelagica Pall., Zoog. Kosso-As. i. 1826, 343, pi. 1. Thalassoaetus pelagicus Kaup, Mus. Senck. 

 Hi. 1846, 261. 



