Bulletin - United States National Museum - si-pddr - Smithsonian ...

112 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
form with which it is identified. An immature male from Rio Negro,
Uruguay, secured February 15, is also slightly intermediate in its
characters.
Hellmayr '•'^ has proposed to replace the subspecific name yucKerani
by su'perciliaris from Sparvius superciliaris Vieillot^* based on the
esparvero pardo ceja hlanca of Azara. Azara, however, says in the
beginning of his description that the feathers of the head and nape
in his bird were pointed, while the remaining plumes of the dorsal
surface had rounded ends, a character not to be found in Rupomis^
so that he must have had some other hawk in mind. Though the
remainder of the description may fit the immature stages of the
present bird, this first statement must identify the bird described
as one of some other genus. It is curious that Azara's Esparvero
indaye, which is undoubtedly a Ruporivis^ was not given a name by
those who republished his descriptions.
This small hawk was common in open wooded regions of the
Chaco in northern Argentina and Paraguay, and was observed in
less abundance in Uruguay. It frequented the borders of groves
where it might perch in the shade or the open as desired. The
caranchillo, as the bird was called, was fearless often to a point of
stupidity, and was seldom alarmed even by a gunshot fired close at
hand. In regions where it was common it came almost invariably
when I was "squeaking" to draw warier denizens of the thickets
from cover, and perched near at hand with jerking tail while it
peered about to locate the sound. Though most other birds were
little afraid the squalling calls of the hawk caused some to remain
partly concealed, and even frightened shyer ones from appearing
at all, so that at times I found Rupornis considerable of a nuisance.
Toward the end of August the mating season seemed near as the
hawks became very noisy, and screaming shrilly, often turned in
short circles two hundred meters in the air, while others squealed in
answer from the tree tops below.
An adult female taken July 26 had the soft parts colored as follows:
Tip of bill dull black, base clear green-blue gray, becoming
deep colonial buff on rami of mandible; cere primuline yellow; iris
massicot yellow ; tarsus and toes honey yellow ; claws black.
These hawks were recorded as follows: Resistencia, Chaco, July
9 and 10; Las Palmas, Chaco, July 13 to 31; Riaqho Pilaga, Formosa,
August 7 to 21; Formosa, Formosa, August 23 and 24; Puerto
Pinasco, Paraguay, September 3 to 25 (observed west to a point 200
kilometers from the Rio Paraguay) ; San Vicente, Uruguay, January
31, 1921 (two seen) ; Rio Negro, Uruguay, February 15 to 18.
The pelvic powder downs in these hawks are well developed.
s^Nov. Zool., vol. 28, 1921, p. 183.
" Nouy Diet. Hist. Nat., vol. 10. 1817, p. 328.