532 SYSTEMATIC SYNOPSIS. — RAPTORES — ACCIPITRES. 
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; Ist longer than 4th, and decidedly emarginate on inner web. (Gyr- 
Falcons, lanners, and peregrines. ) ; 
Gyrfalcons: Tarsus feathéred fully 4 down in front and on sides, leaving but a uarrow 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 7 + + + candicans 501 
Lanners: Tarsus feathered $ way down in ion, icoaaaly bare Tbabind: longer than middle toe 
without claw; 1st quill shorter than 3d. Medium; piace above; sexes alike. (GEN- 
NAIA.) . BY Src » mexicanus 502 
Peregrines: Tars Sus feathered but a little — ‘down in front, broadly — behind ; not longer 
than middle toe without claw; 1st quill not shorter than 3d. Medium: slaty- bluish above; 
sexes alike. (FALCO.). Fi : . peregrinus 503, 504 
Tarsus scarcely feathered above, with ‘the plates: in front enlarged, like a "double row of alternating 
scutella (and often with a few true scutella at base); 2d or 8d primary longest; 1st not longer thar 
4th; 1st and 2d emarginate on inner webs. (Merlins and Kestrels.) 
Merlins: Tarsus longer than middle toe without claw. Sexes unlike; young of both like adult 
female. Small; wing 7.50-8.50. (AZSALON.) & - + columbarius 505, 506, 507 
Kestrels: Tarsus longer than middle toe without claw. "Sexes very unlike at allages. Smallest: 
wing 7.00-7.50. (TINNUNCULUS.) 
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 femalerufous . .. . sparverioides 510 
Hobbies: Tarsus little longer than middle toe without claw. Sexes alike; young little different. 
Medium; wing 10.00 or more (RHYNCHOFALCO.) . . see ew ew « fuscicwrulescens 511 
498. F,sa/cer. (Lat. sacer, sacred.) AMERICAN CONTINENTAL GYRFALCON. One of the largest 
and most powerful of the Falconine. Feet very stout; tarsus rather longer than middle toe 
without claw, feathered fully half-way down in front and on sides, with narrow bare strip 
behind; elsewhere reticulate. Wing pointed by 2d quill, supported nearly to the end by the 
3d; lst rather shorter than 3d, only the 1st decidedly emarginate on inner web. Tail rounded. 
Sexes alike. Young little 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’. gyrfalco 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 cireumpolar species; that with specimens enough 
an uninterrupted series could be established connecting the blackest ‘‘obsoletus” 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- 
ern States in winter, sometimes even reaching the Middle States and Kansas. They reside 
in summer beyond the U. 8., and abound in the Arctic regions, nesting in trees or clifis, preying 
upon hares, grouse, ptarmigan, ducks, auks, ete. The eggs range from 2,25 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.) LasBrapor GYRFALCON. A dark phase of 
the last, almost entirely dusky, the usual markings nearly obliterated ; from the foggy coast of 
