534 SYSTEMA TIC SYNOPSIS. — BAPTOBES— A CCIPITBES. 
503. F. mexica'nus. (Liit mexicanus, Mexican. Fig. 376.) American Lanner Falcon. Prairie 
Falcon. A medium-sized species, distinguished from any gyrfalcon by the smaller size, 
different feathering of the tarsus, etc. ; from the duck hawk by the general much lighter color, 
which is dull brownish above instead of dark slate, etc. Adult J 9 • Upper parts brownish- 
drab, each feather with a paler border of brown, grayish, or whitish ; the top of the head more 
uniform, the occiput and nape showing more whitish. Under parts white, everywhere ex- 
cepting on the throat marked with firm spots of dark brown, most linear on the breast, then 
more broadly oval on the belly, enlarging and tending to merge into bars on the flanks, very 
sparse or obsolete on the crissum, in the maxillary region forming a broad firm moustache; 
these markings corresponding with the ground color of the upper parts. Primaries ashy- 
brown, with narrow but firm pale edging of outer webs and ends, the inner webs regularly 
marked with white in form of barred indents or circumscribed spots, most numerous and regular 
on the outer few primaries ; the white tinged with fulvous, next to the shafts ; the outer web 
of the first primary either plain, or with whitish indents as in F. lanarius ; outer webs of sec- 
ondaries more or less marked with fulvous ; axillars plain dark brown ; lining of wings other- 
wise white, spotted with dark brown. Tail pale brownish-gray, nearly uniform, but with 
white tip, and more or less distinct barring or indenting with whitish, especially on the lateral 
feathers, producing a pattern not unlike that of the primaries. Bill mostly dark bluish hom- 
color, but its base, and much of under mandible, yellow ; feet yellow. Young birds have more 
fulvous in the dark ground of the upper parts ; are more heavily spotted below, and the 
white is there tinged M'itli buff or ochrey, feet plumbeous. Size very variable : length of ^ about 
18.00, extent 40.00 ; wing 12.00-13.00 ; tail 7.00-8.00; tarsus about 2.00 ; middle toe without 
claw about the same; chord of culmen, including cere, 1.00. 9 larger: wing 13.00-14.00; 
tail 8.00-9.00, etc. A noble species, representing the Old World lanner and jugger, and scarcely 
separable therefrom ; abundant in Western N. Am., especially on the plains ; E. occasionally to 
Illinois. I have traced it from Montana at lat. 49° to Arizona and S. California, and found 
it very numerous in Wyoming, where it is the characteristic species of its genus ; it extends 
into Mexico. In the region first named it was nesting on cliffs. Eggs 2-3, from 2.05 to 2.25 
X 1.55 to 1.65, white or creamy -whitish, irregularly but usually thickly clouded, mottled, and 
blotched with reddish -brown ; often with a purplish shade; thus indistinguishable from those 
of related species. (F. 2^olyagrus Cass.) 
503. F. peregri'nus. (Lat. per6f/rwws, wandering. Fig. 377.) Peregrine Falcon. Duck Hawk. 
Great-footed Hawk. A medium-sized falcon, about as large as the foregoing, but known 
at a glance from any bird of N. Am. by the slaty -plumbeous or dark bluish-ash of the upper 
parts, the black moustache," and other marks, taken with its particular size and shape. 
Wings stiff, long, thin, pointed by the 2d quill, supported nearly to its tip by 1st and 3d ; 1st 
quill alone abru])tly emarginate on inner web, this about 2 inches from its tip ; none cut on 
outer webs. Tomium of upper mandible strongly toothed, of under mandible deeply notched. 
Tarsus feathered but a little way down in front, otherwise entirely reticulate ; toes very long, 
giving great grasp to the talons. Adult ^ 9 '■ Above, rich dark bluish-ash or slate-color, 
— very variable, sometimes quite slaty-blackish, again much lighter bluish-slate; the tint 
pretty uniform, whatever it may be, over all the upper parts, but all the feathers with some- 
what paler edges, and the larger ones for the most part obscurely barred with lighter and 
darker hues. Under parts at large varying from nearly pure white to a peculiar muddy buff 
color of different degrees of intensity; the throat and breast usually free from markings (or 
only with a few sharp shaft pencillings) , and this white or light color mounting on the auricu- 
lars, so that it partly isolates a blackish moustache from the blackish of the side of the head; 
the under parts, except as said, and including the under wing- and tail-coverts closely and 
regularly barred, or less closely and more irregularly spotted, with blackish ; the bars best 
pronounced on the flanks, tibiae, and crissum, other parts tending to spotting, which may extend 
