532 SYSTEMATIC SYNOPSIS.— BAPTOBES—ACCIPITBES. 



178. FAl^CO. (Lat. falco, a falcon or faucon.) Characters as above, with minor modifications as 

 follows : — 



Analysis of Subgenera and Species. 



Tarsus more or less feathered above, elsewhere irregularly reticulate in small pattern (no large plates 

 like scutella); 2d primary longest; 1st longer than 1th, and decidedly emarginate on inner web. (G^r- 

 falcons, lanners, and peregrines. ) 



Gerfalcons: Tarsus feathered fully J down in front and on sides, leaving but a narrow strip 

 bare behind ; longer than middle toe without claw ; 1st quill shorter than 3d, Sexes alike. 

 Very large ; about 2 feet long. (Hierofalco.) 



Prevailing color dark ; head and neck darker than back sacer 498, 499 



Prevailing color dark ; head and neck lighter than back islandicus 500 



Prevailing color white candicans 501 



La/liners: Tarsus feathered ^ way down in front, broadly bare behind; longer than middle toe 

 without claw; 1st quill shorter than 3d. Medium; grayish-brown above; sexes alike. (Gen- 



NAIA.) . .... mexicanus 502 



Peregrines : Tarsus feathered but a little way down in front, broadly bare behind ; not longer 

 than middle toe without claw; Ist quill not shorter than 3d. Medium: slaty-bluish above; 



sexes alike. (Falco.) peregrinus 503, 504 



Tarsus scarcely feathered above, with the plates in front enlarged, like a double row of alternating 

 8cutella(and often with a few true suutella at base); 2d or 3d primary longest; 1st not longer than 

 4th; 1st and 2d emarginate on inner webs. {Merlins aQ(i Kestrels.) 



Merlins : Tarsus longer than middle toe without claw. Sexes unlike ; young of both like adult 



female. Small; wing 7.50-8.50. (^salon.) . . coliimbarins 505,506,507 



Kestrels: Tarsus longer than middle toe without claw. Sexes very unlike at all ages. Smallest: 

 wing 7.00-7.50. (TiHNONCULUS.) 



Under parts white or tawny ; back of male and female rufous, barred or plain sparverius 508, 509 



Under parts rufous; back of male plumbeous, of female rufous sparverio'ides 510 



Bobbies: Tarsus little longer than middle toe without claw. Sexes alike; young little different. 

 Medium ; wing 10.00 or more (Rhtkchofalco.) fuscicoerulescens 511 



498. F. sa/cer. (Lat. sacer, sacred.) Ambhican Continental Gtefalcon. One of the largest 

 and most powerful of the Falconinne. Feet very stout; tarsus rather longer than middle toe 

 without claw, feathered fully half-way down in front and on sides, with narrow hare strip 

 behind; elsewhere reticulate. Wing pointed by 2d quill, supported nearly to the end by the 

 3d; 1st rather shorter than 3d, only the 1st decidedly emarginate on inner web. Tail rounded. 

 Sexes alike. Young Uttle different. Wing of ^13.50-14.50; tail 8.50-9.50; wing of ? 

 15.00-16.00; tail 9.00-10.00. Adults: General plumage of the upper parts barred with dark 

 brown and pale ash, the former predominating, especially on the head and neck ; tail closely 

 barred with light and dark in about equal amounts. Lower parts white, immaculate on 

 throat, elsewhere streaked and variously spotted with dusky. Young darker than the adults ; 

 at an early stage, some of the lighter markings tinged with ochraceous. This is the stock- 

 form of Continental N. Am., probably inseparable from F. gyrfako of Europe ; the distinctions 

 from F. islandicus being moreover not very apparent. I suspect the truth to be, in respect to 

 all the gyrfalcons, that there is but a single oiroumpolar species ; that with specimens enough 

 an uninterrupted series could be established connecting the blackest " obsoletiis " with the 

 whitest " candicans'' ; and that the races even, which most ornithologists recognize, are not 

 coincident with geographical areas. But I defer in this case to those authorities who have 

 formed the contrary opinion, upon much further investigation of the subject than I have 

 ever made. Gyrfalcons of the present kind, or of Nos. 499, 500, not infrequently visit the North- 

 em States in winter, sometimes even reaching the Middle States and Kansas. They reside 

 in summer beyond the U. S., and abound in the Arctic regions, nesting in trees or cliffs, preying 

 upon hares, grouse, ptarmigan, ducks, auks, etc. The eggs range from 3.25 to 2.50 in length, 

 X 1.60 to 1.90 in breadth, and are usually heavily colored with reddish and brownish pig- 

 ments in interminable variety. 

 499. F. s. obsole'tus. (Lat. obsoletus, unwonted.) Labrador Gtefalcon. A dark phase of 

 ^he last, almost entirely dusky, the usual markings nearly obliterated ; from the foggy coast of 



