354b. BLACK GYRFALCON. _Falco rusticolus obsoletus._ Range.--Labrador; south casually, in winter, to Long Island. A slightly darker variety. Eggs indistinguishable. Data.--Ungava coast, Labrador, May 25, 1900. Nest a heap of seaweed and feathers on sea cliff, containing three eggs. 355. PRAIRIE FALCON. _Falcon mexicanus._ Range.--United States west of the Mississippi, and from Dakota and Washington southward to Mexico. This species abounds in suitable localities, generally placing its nests upon rocky ledges and cliffs, and sometimes trees, generally upon the banks of some stream. The nests are masses of sticks, lined with weeds and grasses. The three or four eggs have a reddish buff ground color, and are thickly sprinkled and blotched with reddish buff brown and chestnut; size 2.05 × 1.60. 356a. Duck Hawk. _Falco peregrinus anatum._ Range.--Whole of North America, breeding locally, chiefly in mountainous regions, throughout its range. This beautiful species, characterized by its black moustache, is the most graceful, fearless, and swiftest of the Falcons, striking down birds of several times its own weight, such as some of the larger Ducks. It breeds quite abundantly on the Pacific coast and in certain localities in the Dakotas, laying its eggs on the rocky ledges. Their eggs are similar to those of the Prairie Falcon, but are darker and brighter, in fact they are the darkest, brightest marked, and most beautiful of Falcon eggs; size 2.05 × 1.55. [Illustration 221: Reddish buff.] [Illustration: Prairie Falcon.] [Illustration: Duck Hawk.] [Illustration: Buff or reddish buff.] [Illustration: right hand margin.] Page 220 356b. PEALE'S FALCON. _Falco peregrinus pealei._ Range.--Pacific coast from northern United States north to Alaska. A darker form of the preceding, such as occurs in this section with a great many other birds. The nesting habits and the eggs are precisely like those of the Duck Hawk. 357. Pigeon Hawk. _Falco columbarius columbarius._ Range.--North America, breeding chiefly north of the United States except in some of the higher ranges along our northern border. A small Falcon, about 11 inches long, often confused with the Sharp-shinned Hawk, but much darker and a more stoutly built bird. It is a daring species, often attacking birds larger than itself; it also feeds on mice, grasshoppers, squirrels, etc. They generally build a nest of sticks in trees, deep in the woods; less often in natural cavities of dead trees; and sometimes on rocky ledges. Their four or five eggs have a brownish buff ground color, heavily blotched with brown and chestnut. Size 1.50 × 1.22. 357a. BLACK PIGEON HAWK. _Falco columbarius suckleyi._ Range.--Pacific coast from northern United States north to Alaska. Very similar in appearance to the preceding, but much darker, both above and below. Its nesting habits and eggs will not differ in any manner from those of the Pigeon Hawk.