FALCONID.E — BUTEONIN.E : EAGLES. 695 



THRASAE'TUS. (Gr. Bpacrvs, tJtrasus, bold ; deros, aetos, an ea_£;le.) Harpy Eagles. A 

 genus contaiuing one species of eiioruuuis size, the most powerful raptorial bird of America, it 

 not of the entire sub-order. Head with a broad flowing occipital crest. Bill of great length 

 and depth, much compressed, S(j hooked that the curve of tlie cuhnen is about a quadrant of a 

 circle; commissure about straiglit, tomia festooned but not toothed ; cere extensive, with nearly 

 vortical fore-edge, close to which are the narrowly oval nostrils, about midway betvA^een tomia 

 and cuhnen ; lores extensively naked and bristly ; superciliary shield prominent ; feet and tal- 

 ons of immense strength ; tarsus feathered a little way down iu front; feet reticulate, excepting 

 a few scales on top of toes ; lateral toes much shorter than middle; inner claw much larger 

 than middle; hinder much the largest of all. Wings rather short, very ample; secondaries 

 entirely covering primaries when folded ; wing as a whole much vaulted, outer quills strongly 

 bowed. Tail long, | the wing, fan-shaped, vaulted. 



T. harpyi'a. (Gr. ap-rrvia, harjmia, a harpy.) Harpy Eagle. The largest and finest 

 specimen before me I judge to have been nearly or about 4 feet long; wing about 2 feet ; the 

 tail 18 inclies ; chord of cuhnen, including cere, 2.75 inches; depth of bill 1.50; tarsus over 

 4.00; chord of hind claw nearly .'].00. Head and entire under parts dull white, more or less 

 obscured with ashy or dusky, particularly on crest, across throat, and on tibiae, which latter are 

 in some cases regularly barred with blackish. Upper parts at large ashy-gray, intimately but 

 irregularly barred with glossy black, especially on wing-coverts. Flight-feathers mostly 

 blackish, but witli more or less ashy nebulation, to which wliitish variegation is added on 

 inner webs. Tail pretty regularly barred with black and ash, in other cases irregularly nebu- 

 lated with light and dark ash. The bill appears to have been blackish, the feet of some yel- 

 lowish color. Young birds are much darker. Central and South America and Mexico, a well- 

 known and most formidable bird of prey, reaching the Texas border of the Lower Rio Grande; 

 also, Louisiana? 



A'QUILA. (Lat. aquiln, an eagle.) Goldex Eagles. Of great size, robust form, and 

 jxiwcrful pliysique, but in technical characters near Buteo and especially Arckibuteo. Tibia 

 extensively flagged. Tarsus closely feathered all around to the toes; toes mostly reticulate on 

 top, margined, outer and middle webbed at base. Hill large, long, very robust ; tomia lobed ; 

 nostrils oval, oblique; superciliary shield prominent. Wings long, pointed by 3d-5th quills, 

 2d sul)equal to (ith, 1st very short, 5 or (i emarginate on inner webs; 2d to 0th or 7th sinuate 

 on outer webs. Tail moderate, rounded, or graduated. Feathers of occiput and nape lanceolate, 

 acute, discrete, like a Raven's throat-plumes. Sexes alike ; clianges of plumage not great. 

 Tliis extensive genus includes Eagles properly so called, of which there are numerous Old 

 World species, but only one American. 



A. chrysae'tus. (Gr. ;(puyafrof, chrusaetos, golden eagle. Fig. 473.) GoLUEX Eagle. 

 Rin(;-taili:i> Eagle. Black Eagle. Mountain Eagle. Adult (J 9 = Dark brown, with 

 jiurplish gloss, lighter on coverts of wings and tail and on flags or tarsi; the cowl of lanceolate 

 fcatlicrs g(dden-hrown. Quills and tail-feathers blackish, but basally more or less variegated or 

 areatcd witli liglit brown, gray, or whitish; at maturity these markings extensive and definite. 

 Young birds blacker than adults, wliich " grow gray," witli age, and are "ring-tailed," — that 

 is, basal portion and finally most of tail white, offset by a broad black terminal zone. Length 

 aljout .'ncct (or more); extent (i or 7 feet; wing 2 feet (^) or more (9); t:ii' 14.00-J5.00 

 incii('s((^) or more ( 9 ) ; bill, without cere, J. 50-1. 75; tarsus 3.50-4.00. This great bird 

 inhabits North America at large, as well as Europe, Asia, etc. ; in this country rather nortlicrly, 

 S. onhuarily to about 35°. The American is not fairly distinguished from the European, but on 

 the whole is a larger and " better" bird, like several others of the present family, as well as 

 of the goose and duck tribes. This I suppose to bo owing t«> tlie fact that there is more room 

 for them, more food, less persecution, and altogether less competition in tlie struggle for exist- 

 ence. It breeds chieliy in njoiiutaiuous or boreal regions, tlie eyrie being usually upon a crag, 



