_Asturina_, VIEILL. 1816. (Type, _Falco nitidus_, LATHAM.)
GEN. CHAR. Somewhat similar to _Astur_, but of much heavier and more
robust build; tarsi longer and stouter, tail shorter and less rounded,
wings longer, etc. Bill more elongated than in _Astur_, the cere
longer, and the festoon on the commissure more developed; nostril
oval, horizontal. Wings rather short, but less concave beneath than
in _Astur_; third to fourth quill longest; first shorter than eighth
or ninth; four outer quills with their inner webs sinuated. Tail
considerably shorter than the wing, slightly emarginated, the lateral
pair of feathers longest. Feet large and robust, when outstretched
reaching almost to the end of the tail; tarsi very robust compared to
the toes, about one and a half times as long as the middle toe, the
frontal and posterior rows of transverse scutellæ very distinct and
regular; outer toe longer than inner; claws strong, well curved, but not
very acute. Sexes alike in color; old and young plumages very different.
[Illustration:
=34002=, ♀. ½
=34002=, ♀. ¼
=34002=, ♀. ½
_Asturina plagiata._]
This genus is peculiar to tropical America, and contains but a single
species, the _A. nitida_, with its two climatic races, _nitida_ of South
America and _plagiata_ of Middle America. The species of _Rupornis_,
Kaup (_R. magnirostris_ and _R. leucorrhoa_), have been associated with
the species of the present genus, but they are very distinct. The genera
(or, more properly, subgenera) most nearly related to _Asturina_ are
_Leucoptrinis_, Kaup, of tropical America, and _Kaupifalco_, Bonap.,
of Western Africa. The former differs mainly in more or less rounded,
instead of emarginated, tail, and in having the old and young plumages
similar; the latter in having the posterior face of the tarsus without a
well-defined row of transverse scutellæ.
Species and Races.
=A. nitida.= Wing, 9.80–11.50; tail, 6.70–8.00; culmen, .80–1.00;
tarsus, 2.50–2.90; middle toe, 1.40–1.75. _Adult._ Above clear
ash, paler on the head and darker on the rump; the general surface
with more or less appreciable transverse bars, or indications of
bars, of a paler shade, and with darker shafts. Upper tail-coverts
immaculate white. Tail deep black, fading into pale grayish-brown
at the end, narrowly tipped with white, and crossed by two to three
white bands. Lower parts, including the tibiæ, axillars, and throat,
regularly barred with deep ash and white, the two colors about
equal in extent; chin and crissum immaculate white. _Young._ Above
blackish-brown, variegated with pinkish-ochraceous. Tail umber, tipped
with pinkish-brown or dull whitish, and crossed by six to seven narrow
bands of black. Beneath white, sometimes tinged with ochraceous; the
breast, abdomen, and sides with longitudinal tear-shaped spots of
black.
_Adult._ Upper surface distinctly barred, the lighter bars
predominating; the top of the head as distinctly barred as the lower
parts. _Young._ Tibiæ immaculate white or pale ochraceous. Culmen,
.80–.90. _Hab._ South America, from S. E. Brazil and W. Ecuador, to
Panama …
var. _nitida_.[84]
_Adult._ Upper surface only obsoletely barred, or almost uniform;
the top of the head without any bars. _Young._ Tibiæ transversely
barred with dusky. Culmen, .75–.80. _Hab._ Middle America, north to
the southern border of the United States; straying northward in the
Mississippi Valley, to Southern Illinois …
var. _plagiata_.
Asturina nitida, var. plagiata (SCHLEG.).