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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 307
the long, pointed wings, gray back, and black tail with its light
border that form the characters by which the bird may be recognized
in the field. The flight is strong and certain, and the birds alighted
alertly with head erect. All noted were silent. On March 17, along
the Rio Mendoza below Potrerillos, they were in passage downstream
in small parties that appeared to be in migration from the higher
altitudes,
A female, taken November 29, had the base of the mandible cream
buff ; remainder of the bill black ; iris Hay's brown ; tarsus and toes
black.
LESSONIA RUFA RUFA (Gmelin)
Alauda rufa Gmelin, Syst. Nat, vol. 1, pt. 2, 1789, p. 792. (Buenos Aires.)
Mathews ®2 shows that Alauda nigra Boddaert for this species is
antedated by Alauda nigra of the same author for another bird so
that the specific name becomes rufa of Gmelin.
This ground-inhabiting flycatcher was recorded at the following
localities: Berazategui, Buenos Aires, June 29, 1920 (adult male
taken) ; Santa Fe, Santa Fe, July 4; Zapala, Neuquen, December 8
and 9 (two adult males shot) ; Carrasco, Uruguay, January 16, 1921;
Guamini, Buenos Aires, March 3 to 8 (four males, three females
taken) ; Tunuyan, Mendoza, March 22, 23, and 27 (adult male shot)
and Concon, Chile, April 23 (adult male taken). Twelve skins were
secured in all. Birds from Zapala, shot in summer, were in full
breeding plumage. Four males, shot in March at Guamini, were all
in immature plumage, in which they are similar to females, save
that the back is more rufescent. One shows distinct signs of molt,
apparently from a juvenal plumage. On this basis the young males
molt from a juvenal plumage into a first winter plumage that is
similar to the dress of the female. A specimen taken in September
at Conchitas, Buenos Aires (in the United States National Museum),
is in molt from the dull winter dress into the black adult plumage. On
this slender evidence it may be supposed that the young males assume
adult dress by a prenuptial molt in spring. An adult male, shot
at Tunuyan March 27, in full adult plumage, is renewing the outer
primaries. A skin in the United States National Museum, taken
in April at Conchitas, has the throat white and the lower surface
mottled with whitish. Other winter taken adult males do not differ
from breeding specimens, save for an occasional specimen with very
faint whitish tips on the feathers of the lower surface. It is common
usage in recent years to consider Lessonia oreas,^^ which differs
from nigra in larger size and whitish edgings on the inner webs
'^Austr. Av. Rec, vol. 3, Nov. 19, 1915.
s^Centrites areas Sclater and Salvin, Proc. Zool. Soc. London, 1869, p. 154. (Tinta,
Peru.)
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