304 FALCONS, CARACARAS, ETC. 



354. Falco rusticolus rusticplus (Linn.}. GRAY GYRFALCON. Ads. 

 Head streaked with buffy or whitish and fuscous, in about equal amounts; 

 upperparts grayish, slaty or brownish gray barred with white or whitish; 

 tail barred with brownish gray and white in about equal amounts; below 

 white with elongate spots from chin to vent; flank plumes barred, under 

 tail-coverts barred or with shaft-streaks. Im. Head more narrowly streaked 

 with fuscous; upperparts browner margined with whitish and with more or 

 less concealed spots or broken bars of whitish or buffy; underparts more 

 heavily streaked. L., 20'00; W., 15'50; T., 9'50; B. from N., '90. 



Remarks. In any plumage the various races of rusticolus are to be 

 distinguished from islandus by their barred, streaked, or shaft-streaked 

 under tail-coverts. The distinctive characters of our three races of rusticplus 

 are the broadly-streaked head of F. r. rusticolus, the barred or margined 

 back and solid or comparatively unstreaked head of gyrfalco, and the black 

 back and almost black underparts of obsoletus^. 



Range. Arctic regions. Breeds in Arctic Am. from Alaska, e. to s. 

 Greenland; in winter casual s. to B.'C., Kans., Wise., Ont., and Maine. 



Nest, on cliffs or in trees. Eggs, 3-4, not distinguishable from those 

 of the preceding, 2'37 x 172. Date, Iceland, Apl. 15 (Thayer Coll.). 



35 la. F. r. gyrfalco (Linn.}. GYRFALCON. Similar to F. r. rusticolus 

 but darker; ad. less distinctly barred above and with the head fuscous, 

 unstreaked. Im. Head grayish brown, little if at all streaked or margined 

 with buffy; back grayish brown, almost uniform, or but slightly margined 

 or spotted with buffy. 



Range. Arctic regions. Breeds in Ellesmere Land, n. Greenland, and 

 e. to Franz Josef Land; in winter casual s. to Minn., N. Y., R. L, Mass., 

 and Maine. 



Nesting date, Ft. Anderson, Mack., May 9. 



354b. F. r. obsoletus (GmeL). BLACK GYRFALCON. Head fuscous, 

 narrowly margined with buffy, rest of upperparts uniform slaty fuscous, 

 without bars; tail the same, without or with only broken bars; underparts 

 of the same color as the back ; the feathers with partly concealed buffy spots 

 or margined with buffy. 



Range. Breeds in Ungava; s. in winter to N. S., Que., Ont., and Maine, 

 and casually to N. Y., N. H., Mass., and R. I. 



Nesting date, Ft. Chimo, Lab., May 22. 



355. Falco mexicanus Schleg. PRAIRIE FALCON. Ads. Above, 

 grayish brown; primaries and inner webs of all but the middle tail-feathers 

 with numerous buffy bars or spots; below, white, streaked and spotted with 

 dark grayish brown. Im. Similar, but with the upperparts margined with 

 ochraceous-buff or. buffy. <? L., 17'00; W., 12'20; T., 7'00. 



Range. Transition and Sonoran zones from e. border of the Great 

 Plains and from s. B. C. and se. Sask. to s. L. Calif., and s. Mex.; casual e. 

 to Minn, and Ills. 



Nest, on cliffs, sometimes in hollow trees. Eggs, 2-5, "creamy white, vin- 

 aceous-white, or pale vinaceous-buffy, sprinkled, speckled, or irregularly 

 spotted with madder-brown, 2*06 x 1*60" (Ridgw.). Date, Gilmer, Wyo., 

 Mch. 25. 



"The Prairie Falcon, as the names implies, is a typical plains bird, 

 and inhabits the dry interior. . . . 



"The flight of this Hawk is swift and graceful, though in most 

 cases it is carried on at no great distance from the ground. It is not 

 a shy bird, except in sections where it has been persecuted and has 

 learned that man is its worst enemy' 7 (Fisher). 



