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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 73
probable that with extensive material two or more forms may be
separated.
COSCOROBA COSCOROBA (Molina)
Anas Coscoroha Molina, Sasg. Stor. Nat. Chili, 1782, p. 234. (Chile.)
The coscoroba was first observed on November 15, 1920, at the
raouth of the Rio Ajo, Lavalle, Buenos Aires, when four passed in
companj' with flamingos. Other white birds that I took to be this
species were noted occasionally flying across the marshes, but none
came Avithin gun range. On January 31, 1921, at the Laguna Castillos,
near San Vicente, Uruguay, I found a considerable number
gathered on open shores with Cygnus Tnelancorifhus. The white
coloration of these fine birds, especially when massed in flocks, made
them conspicuous at long distances, and they were correspondingly
v^ary. Before I was able to creep up within 100 meters the flocks
flew out a meter into the lagoon, and then swam away over the high
waves out of range, to return when I had passed. At rest they appear
entirely white, but as the wings are extended the black at the
tips of the primaries is revealed. The bill appears to be light red-
dish in color. No specimens were taken.
DAFILA SPINICAUDA (Vieillot)
Anas spinicauda Vieillot, Nouv. Diet. Hist. Nat., vol. 5, 1816, p. 135.
(Buenos Aires.)
Six adults of the southern pintail were collected near Lavalle in
Buenos Aires as follows? One female on November 2, 1920, another
on November 3, and three males and one female on November 6. An
adult male taken November 2 was preserved as a skeleton. In addi-
tion to the usually recognized characters of longer tail and greenish
black speculum used to distinguish males from females, it may be
noted that in females the throat is so nearly immaculate as to ap-
pear almost white, while in males it is strongly spotted. In a small
series of these birds from Chile, Argentina, Paraguay, and Peru,
I am unable to detect differences in size or coloration that may be
correlated with geographic range.
An adult secured at Lavalle had the soft parts colored as follows
Stripe down culmen nearly to nail, nail and margin of maxilla ad-
jacent, serrate margin of bill, and tip of mandible including nail,
black; space behind nail on maxilla and mandible gray number 7;
rest of bill mustard yellow; iris Vandj^ke brown; tarsus and toes
olive gray, clouded on joints with neutral gray; webs slate color.
The coloration of young in the down, less than a week old, taken
from one of four specimens secured at General Roca, Territory of
Rio Negro, on November 27 is as follows (Cat. No. 283,675, U.S.N.M.
male) ; forepart of crown buffy brown, becoming clove brown, mixed
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