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

100 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
noiseless, so that the downy margins on the flight feathers seem to
serve to deaden the sound of the wings. In life the facial niif was
almost as prominent as in the marsh hawk.
Swann^^ has described a subspecies from Sarayacu, Ecuador, as
huckleyi on basis of small size. Specimens available agree more or
less in measurement throughout the entire range of the bird, so
that it is possible that this bird from Ecuador, with a wing measurement
of only 217 mm., may be an aberrant specimen or may belong
elsewhere.
My skin from Paraguay is a male (apparently in its second year)
of the extreme of the rufescent phase for this species. The dorsal
surface is entirely warm brown in color, with the transverse lighter
markings on wings and back more definitely indicated than is usual.
A few dusky feathers are in evidence on the crown and back. It
measures as follows: Wing, 246; tail, 248; culmen from cere, 18;
tarsus, 81.5 mm.
SPIZIAPTERYX CIRCUMCINCTUS (Kaup)
Earpagus circumcinctus Kaup, Proc. Zool. Soc. London, 1851 (pubL Oct.
28, 1852), p. 43. (" Chili "= Argentina.)
This rare hawk was found in small numbers near Victorica,
Pampa, on December 23, 27, and 28, where three specimens were
secured, a. pair on December 23 and an adult male on December 28.
The birds frequented the larger growth of woodland in this
region, usually where the forest of heavy-limbed, stocky trees was
fairly open. To avoid the intense rays of the sun, they chose shaded
perches in such trees as the calden, where the foliage was confined
largely to the tips of the branches and did not obscure the outlook
below or at the side. Attention was drawn by the querulous whining
calls of these falcons, similar to a note of the brown thrasher, but
given in a much louder tone. At times the birds, rather tlian fly,
hopped agilely through the limbs to place a screen of branches
between themselves and the observer. Their flight was direct, like
that of a small falcon, with the white rump displayed as a prominent
identification mark. When they appeared in the open they were
pursued hotly by fork-tailed flycatchers and other related species.
The birds taken were breeding (though no nests were observed) and
were in somewhat worn plumage. (PI. 9.)
An adult female shot December 23 had the tip of the bill dull
black; base of maxilla light grayish olive; base of mandible mignonette
green ; cere, gape, skin of lores, and bare skin about eye wax
yellow; iris light cadmium; tarsus and toes slightly paler than
deep colonial buff; nails black.
« Syn. Accipitres, ed. 2, pt. 1, Sept. 28, T921, p. 25.