GEN. CHAR. Bill strong, its breadth at the base equalling or exceeding
its height; upper outline of cere on a level with, or rather lower
than, the base of the culmen; gonys much arched, the chord of the arch
equalling about half that of the culmen. Near the tip of the upper
mandible is a prominent tooth on the commissure, and near the end of the
lower mandible, which is truncated, is a deep notch corresponding; the
end of the upper mandible is compressed, giving the situation of the
tooth an inflated appearance when viewed from above. Nostrils circular,
with a conspicuous central tubercle. Orbital region bare; projecting
superciliary shield conspicuous, arched, but not very prominent. Tail
shorter than wing, the feathers hard and stiff. Primaries very strong,
elongated, tapering rapidly toward their points; only the first or first
and second with their inner webs emarginated, the cutting being angular,
and near the end of the quill. Tarsus never with a single series of
transverse scutellæ either in front or behind; middle toe very long.
[Illustration: =13077=, ♀. ½]
Subgenera.
One primary only with inner web emarginated; first to second longest;
first longer than fourth.
Tarsus longer than middle toe, and feathered far below the knee;
first quill shorter than third. Coloration of the sexes alike; old
and young slightly different in pattern and tints. Size large …
_Hierofalco._
Tarsus not longer than middle toe, and scarcely feathered below the
knee; first quill equal to or longer than the third. Coloration of
the sexes alike; old and young very different in pattern and tints.
Size, very small to large …
_Falco._
Two primaries with inner webs emarginated; second to third longest;
first shorter than fourth.
Basal joint of toes without transverse scutellæ; tarsus about equal
to middle toe.
Coloration of the sexes in adult plumage very different in tints;
in the young alike, the young ♂ resembling the adult ♀. Size
small …
_Æsalon._
Basal joint of toes with transverse scutellæ; tarsus longer than
middle toe.
Coloration of the sexes very different, in pattern and tints, at
all ages; old and young alike. Scutellæ of the toes and tarsus
interrupted at the digito-tarsal joint; tarsus much longer than
middle toe. Bill small, the cere on top less than one fourth the
culmen. Size small …
_Tinnunculus._
Coloration of the sexes alike at all ages; old and young slightly
different in pattern and tints. Scutellæ of tarsus and toes
uninterrupted from “knees” to claws; tarsus but little longer
than middle toe. Bill large, the cere on top about one third the
culmen. Size medium; form very slender …
_Rhynchofalco._