207 
browns instead of dark brown, black, or bluish-grey. Below, the dark markings are less 
extensive, and never predominate over the white. Like the much rarer and larger Gyr- 
falcon, the first primary is shorter than the third, instead of being equal or longer. 
Field Marks. Recognized as a Falcon by sharp triangular wings, fairly long tail, 
seldom spread in flight, rapid wing beat without sailing, and the repetition of a single harsh 
note when agitated. Very much like the Peregrine Falcon in size, outline, and action (See 
Figures 202-8 and 231), from which it is best distinguished in life by its pale, sandy color- 
ation. 
Nesting. On cliffs, in crevices, or under overhanging ledges, in the most arid localities. 
Distribution. Western North America, south to southern Mexico. In Canada, the 
prairie regions of Saskatchewan and Alberta and the valleys of southern British Columbia. 
The Prairie Falcon is the prairie and desert representative of the 
Peregrine and resembles that species in many ways. It has the same 
bold dash and gallant hardihood, but shows more inclination to prey on 
small mammals, instead of birds. On occasions it even turns seriously to 
grasshoppers and the crop of at least one specimen examined by the writer 
was filled with these insects. Of 8 other stomachs examined, 3 contained 
game birds; 5, other birds; 2, mammals; and 2, insects. The above is 
not a very reassuring record for the species, but it is a bird of the arid 
wilds and except in the neighbourhood of typical bad lands is rarely numerous 
enough to have any decided economic effect. The greatest complaint that 
can be normally laid against it is its tendency to visit the vicinity of grain 
elevators on the edges of prairie towns, and prey upon the domestic pigeons 
attracted by the spilled grain. 
356. Peregrine Falcon (Including Duck Hawk and Peale's Falcon). Falco 
peregrinus. L, about 18. Plate XXVII B. Adult: slaty blue above, slightly barred and 
lightest on rump, darkening to black on crown and tip of 
tail. Below, white to cream, sharply barred with black on 
abdomen, flanks, and thighs. 
Juvenile: dark brown above, slightly feather-edged with 
lighter. Below, dark brown, with broad feather-edges of 
cream, producing a striped effect but tending to bars on 
flanks. Breast, flanks, and upper abdomen with dark pre- 
dominating; throat and lower abdomen lighter. 
Distinctions. Recognizable as a Falcon by toothed bill 
(Figure 229) and pointed wing (Figure 228). Rather 
variable in size, but with above distinctions only likely to 
be confused with the Prairie Falcon. The juvenile 
Peregrine, however, is a dark brown, instead of a sandy, 
coloured bird, and the underparts may approach a solid 
brown, relieved by feather-edge stripes of cream to rufous- 
buff, instead of white or cream ground, with sparse brown 
spots or stripes. 
The adult is distinctly slaty colour on the back, lightest 
on rump, darkest to nearly bfack on head and tail tip — 
colours that never occur on the Prairie Falcon. The faces 
of these two Falcons are distinctive, with a dark bar down each side of the face from the 
gape, a detail that can be seen for considerable distance. The first primary, when full 
grown, is usually longer than the third, sometimes equal to it, but very rarely shorter. 
Figure 231 
Peregrine Falcon. 
Showing characteristic wing action 
and outline in flight. 
Field Marks. Recognized as a Falcon by sharp, triangular wings, fairly long tail 
seldom spread in flight, rapid wing beat without sailing, and wings descending on the down 
stroke as far as they ascend on the up beat (Figure 231). The note when agitated is a 
rapid repetition of a harsh ‘ t Kack-kack-Kack-etc. ,> Hardly distinguished from the 
Prairie Falcon by size, outline, or action, but of stronger, darker coloration, nearly black 
above instead of sandy in adult, and the dark predominating in the underparts of the 
juvenile. 
Nesting. On cliff ledges, but never under shelter of strong overhangs ,or in clefts; and 
always (?) in the immediate vicinity of water. 
