532 SYSTEM A TIC SYNOPSIS. — RAPTORES— A CCIPITBES. 
178. FAL.'CO. (Lat. falco, a falcon or faucoii.) 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 4th, and decidedly emarginate on inner web. {Gyr- 
falcons, lanners, and peregrines. ) 
Gyrfalcons: Tarsus feathered fully ^ 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 
Lanners : 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- 
^-"^i^-) mexicanus 502 
Peregrines : Tarsus feathered but a little way down in front, broadly bare behind ; not longer 
than middle toe without claw; 1st 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 
scutella (and often with a few true scutella at base); 2d or 3d primary longest ; 1st not longer than 
4tli; 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. (^salon.) coiumbarius 505,506,507 
Kestrels : Tarsus longer than middle toe without claw. Sexes very unlike at all ages. Smallest : 
wing 7.00-7.50. (Tijjnunculus.) 
Under parts white or tawny ; back of male and female rufous, barred or plain sparvei-ius 508, 509 
Under parts rufous; back of male plumbeous, of female rufous sparverio'ides 510 
Hobbies : Tarsus little longer than middle toe without claw. Sexes alike ; young little different. 
Medium ; wing 10.00 or more (Rhynchofalco.) fuscicoirulescens 511 
498. F. sa'cer. (Lat. sacer, sacred.) American Continental Gyrfalcon. One of the largest 
and most powerful of the Falconince. 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; 1st rather shorter than 3d, only the 1st decidedly emarginate on inner web. Tail rounded. 
Sexes alike. Young little different. Wing of 13.50-11.50; tail 8.50-9.50; wing of 9 
15.00-16.00; tail 9.00-10.00. Adults: General plumage of the upper parts barred with dark 
bro\ATi 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 circumpolar 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. S., and abound in the Arctic regions, nesting in trees or cliffs, preying 
upon hares, grouse, ptarmigan, ducks, auks, etc. 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. ohsoletus, unwonted.) Labrador Gyrfalcon. A dark phase of 
the last, almost entirely dusky, the usual markings nearly obliterated ; from the foggy coast of 
