FA L CONID.E — FA LCONIN.E : FA L CONS. 667 



top of head and back of neck darker instead of lighter tlian other upper parts, the crown often 

 plain dusky ; barring of back and wing-coverts indistinct, the dark there prevailing over the 

 light markings ; under ])arts never whitey tliroughout, much obscured witli gray, and heavily 

 marked with blackish on the sides, flanks, flags, and crissum ; lieavy blackish moustaches ; 

 tail closely barred with light and dark bands of about equal widths. J wing 13.50-14.50 ; 

 tail 8.50-9.50 ; 9 wing 15.00-1 (5.00; tail 9.00-10.00; dimensions thus not distinctive. Young 

 darker than the adults ; at an early stage, some of the light markings tmgcd with ochraceous. 

 This is the ordinary Gerfalcon of continental America, also found in Greenland, and in- 

 separable from that of continental Europe; it inhabits Arctic America from Labrador to Alaska 

 (probably never reaching as high latitudes as islandus) in the breeding season, and ranges 

 freely S. in winter over the border of the U. S., sometimes reaching southern New England, 

 the Middle States, Kansas, etc. It abounds in its summer home, mostly N. of kit. 65°, where 

 it breeds, and preys on hares, Grouse, Ptarmigan, Ducks, Auks, etc. The nest is built in a tree 

 or on a cliff", indiff"erently, of sticks, twigs, mosses, grasses, feathers, etc, and the eggs are laid 

 from the middle of May to that of June; eggs 3-4, with the usual variation in size, shape, 

 and color, indistinguishable from those of other Gerfalcons; they range from 2.25 to 2.50 long 

 X 1-70 to 1.90 broad, and are usually heavily colored with reddish and brownish pigments in 

 interminable variation, to an extent which almost entirely hides the ground color. Principal 

 synonyms: F. gi/rfaJco Linn. S. N. 10th ed. 1758, ]). 91 ; 12th ed. 1766, p. 130, and of most 

 authors. F. sacer Forster, Philos. Trans. Ixii, 1772, p. 382. F. sacer, var. /3, Gm. S. N. 

 1788, p. 273 (from Forster). F. sacer Cassin, IJ. Cal. 1853, p. 89, in part (includes islandus, 

 as above, and lahradora. as below ; excludes rusticolus, as above). F. sacer var. gyrfalco 

 COUES, Key, 1872, p. 213. Falco (Hierofalco) gyrfalco, var. sacer and var. gyrfalco Ridgw. 

 in Bd. Brew, and IIidgw. Hist. X. A. B. iii, 1874, pp. 108, 115. F. sacer Coues, Key, 

 2d ed. 1884, p. 532, name restricted to the present subspecies. F. rusticolus gyrfalco Stej. 

 Auk, Apr. 1885, p. 187. — This subspecies is Ridgw. No. 412 h, Coues No. 498, A. 0. U. 

 No. 354 a. 



F. (H.) r. obsole'tus. (Lat. ohsoletus, unwonted ; obsolete, as the pattern of coloration is in 

 this case.) Black Gvrfalcon. Labrador Gyrfalcon. A dark phase of the last, al- 

 most entirely dusky, the usual markings nearly obliterated; from the foggy coast of Labradoi, 

 where it breeds on cliff's, .S. in winter to New England and New York. In extreme cases it is 

 quite black, unmarked. There is no difference in measurements, and the eggs are indistin- 

 guishable. I suspect the truth to be, in respect to all the Gyrfalcons, that there is but a single 

 circumpolar species ; that with specimens enough an uninterrupted series could be established 

 connecting tlie blackest " ohsoletus" with the whitest " caudicans '' ; and that the races which 

 most ornith(dogists recognize, are not coincident with geographical areas. F. holboelli of Mr. 

 Sharpe appears to be somewhat of a connecting link between the two species now generally 

 considered distinct. But I defer in this case to those who have formed the contrary opinion, 

 upon further investigation of the subject than I have made. F. ohsoletus, G\n. Syst. Nat. 1788, 

 p. 268. F. labr((dora, Aud. f(dio jd. 196, ])ub. about 1834. Falco (Hierofalco) sacer, var. 

 labradora Ridgw. in Bd. Buew. and Hidgw. Hist. N. A. li. iii, 1874, p. 108 and p. 117. 

 F. sacer ohsoletus CouE.s, Key, 2d ed. 1884, p. 532. F. rusticolus ohsoletus Stej. Auk, 1885, 

 p. 187. Ridgw. No. 412 c, Coues, No. 499, A. 0. U. No. 354 b. 



F. (H.) mexica'nus. (Liit. vie.vicanus, 'Slcxk-a.n. Figs. 456, 459.) American Laxxeu Fal- 

 con. Prairie Falcon. A medium-sized species, distinguished from any Gyrfalcon by smaller 

 size, different feathering of tarsus, etc.; from the Hnck Hawk by mnch lighter c<dor, which is 

 dull brownisii above instead of dark slate, etc. Adult ^ 9- I'i>pi'i' parts l)rownish drab, each 

 feather with a paler border of brown, grayish, or whitish; top of head more uniform, occiput 

 and nape showing more whitish. Under parts white, everywiiere excepting tui throat marked 

 with firm spots of dark brown, most linear on breast, then more broadly oval on belly, enlarg- 



