698 SYSTEMATIC SYNOPSIS.— RAPTORES — ACCIPITRES. 



orous ; a piratical parasite of the Osprey : otherwise notorious as the emblem of the republic. 

 There is a sort of jingoism about this bird which tickles the fancy of the average American 

 patriot, who imagines that it can be heard around the world when it rumples up its feathers 

 and screeches, making as much noise as a liritish lion with its tail twisted. It sometimes 

 fishes for itself, at others stoops to carrion like a vulture, and also preys upon water fowl and 

 mammals of considerable size. The nest is bulky, finally acquiring huge dimension by 

 annual accretions, generally placed high in a tail tree, often also on a clifi", bluff, or cut- 

 bank, rarely on level ground; eggs usually two, of whicli one is larger than the other, probably 

 hatching opposite sexes, sometimes 3, or only one ; average size 2.90 X 2.25, with extremes 

 of 3.05 X 2.35 and 2.45 X 2.00; color white, normally unmarked, rarely with a few spots. 

 Tliey are laid from November all through the winter on our southern border, all through the 

 spring in most latitudes, ov not till early summer in the far North. 



H. 1. alasea'uus. (Lat. Alaskan. Fig. 475.) Alaskan Bald Eagle. Averaging some- 

 what larger. Wing 24.00-24.50; taU 11.50-12.00 ; tarsus 4.00 ; bill 2.50, its depth at base 

 1.50: thus at extremes of size for this species. Alaska; type from Unalaska Island. C. H. 

 TowNSEND, Pr. Biol. Soc Wasli. xi, June 9, 1897, p. 145 ; A. 0. U. Suppl. List, Auk, Jan. 

 1899, p. 109, No. 352 a. 



Obs. Thalassaetus pelagicus. (Gr. 6aKacr(Ta, Thalassa, the sea, ocean; Lat. pelagicuSy 

 pelagic, oceanic, marine.) White-shouldeked !Sea Eagle. Kamtschatkan Sea Eagle. 

 This most magnificent of the Eagles is found on the Commander Islands in Bering's Sea, as 

 well as on the Asiatic mainland, and no doubt sometimes files across to the neighboring Aleu- 

 tian islands, as our Bald Eagle easily makes the same fiiglit in the opposite direction, thus 

 figuring as a bird of Asia. A fair exchange would be no robbery, but we have no authentic 

 data for introducing the genus and species formally in the Key. Adult $ 9 • Dark brown ; 

 forehead, most of the wing-coverts, tail, rump, and thighs, pure white ; bill and feet chrome- 

 yellow ; iris pale yellow. Length of $ over 3 feet ; extent 7\ feet ; wing nearly 2 feet ; tail 14 

 inches, cuneate, graduated 4.00, with 14 feathers ; bill 2.50. 9 larger ; length nearly 4^ feet; 

 extent nearly 8 feet ; wing 2 feet or more. The great white area on the wings, involving the 

 lesser and middle coverts, is very conspicuous. Young birds are darker than the adults, 

 have the white parts more or less mixed with dusky, according to age, and the bill is not 

 bright yellow. 



Family PANDIONID^ : Fish Hawks ; Ospreys. 



See page 619. Plumage i)eculiar, close and firm, imbricated, oily, lacking after- sh afts ; 

 head densely feathered to eyes ; occipital feathers lengthened ; legs closely feathered, with- 

 out any sign of a fiag ; quills of wings and tail acuminate, stiff and hard; primary coverts of 

 similar character. Feet immensely hirge and strong, rouglily granular-reticulate ; tarsi little 

 featliered above in front ; toes all free to the base, the outer versatile. Claws very large, all 

 of equal lengths, subcylindric or tapering terete, not scoo[)ed out underneath, but all com- 

 pressed, and middle one sharply grooved on inner face. Bill toothless, contracted at cere, else- 

 where inriated, with very large hook ; gonys convex, ascending ; nostrils oval, oblique, without 

 tubercle, in edge of cere. The peculiarities of the plumage and of the feet are in evident 

 adaptation to the semi-aquatic piscivorous habits of these '' fishing hawks," which require a 

 water-proof covering, and great talons to grasp their slippery quarry- The structural char- 

 acters are rather those of buteonine than falconine birds of prey, in the coracoid arrangement, 

 etc. The tarso-metatarsus has a bony canal for the passage of the common extensor of the toes, 

 as in most Owls. The synqielmous condition of the flexor tendons occurs as in Falconidce, 

 but with the modification tluit while the flexor perforans has 3 tendinis for the 2d-4th toes the 

 flexor hallucis splits into four, which thus also supply the same 2d-4th toes as well as the 1st. 



