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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 43
or two complete and a series of skulls. Fishermen there told me
that it was frequent to find these birds along the beaches in winter
and apparently there is heavy mortality among them. The pajaro
nino, as the penguin is called, was also reported as frequent on the
eastern coast of the Province of Buenos Aires.
Order COLYMBIFORMES
Family COLYMBIDAE
COLYMBUS DOMINICUS BRACHYRHYNCHUS Chapman
Volymbus dominiciis brachyrhynchus Chapman Bull. Amer. Mus. Nat.
Hist, vol. 12, Dec. 23, 1899, p. 255. (Chapada, Matto Grosso, Brazil.)
On August 9, 1920, near the Riacho Pilaga, 10 miles northwest of
Kilometer 182, Formosa, Argentina, I found two of these grebes
swimming slowly across the open water of a rush-bordered lagoon.
At the time I was navigating a crude balsa made of a bundle of
cattails bound together on which I knelt and paddled with a small
pole. With this unwieldy craft I managed to approach near enough
to secure one of the grebes, but the other dived and was lost in
the rushes.
In the specimen taken the wing measures 102 mm. and the culmen
21.5 mm., so that in size this bird agrees with the measurements
given by Chapman in his original diagnosis of the subspecies hrachy-
rhynchus. It is also slightly darker below than C. d. hrachypterus
Chapman. The present specimen, when compared with a con-
siderable series of hrachypterus^ has the sides of the breast grayer,
and the band across the upper breast lighter in color.
Colynibus doTninicus differs from C. chilensis, the other common
small grebe of this region, in having the outer webs of the inner
primaries and the secondaries margined, at least near the tip, with
dull gray, while the scutes on the tarsus and middle toe are broader
and less numerous. In dominicus the large scutes on the front of
the tarsus number from 12 to 14, and those on the basal joint of the
middle toes from 11 to 12, a total of from 23 to 26 in the combined
spaces. In C. chilensis there are from 15 to 17 scutes on the front of
the tarsus, and 14 to 17 on the basal segment of the middle toe, a
total of from 30 to 34.
Should the small grebe from southern South America prove
separable from northern examples, the name Podiceps speciosus
Felix Lynch Arribalzaga,^" based on a specimen in winter plumage
taken in May, 1873, on Baradero Island, Province of Buenos Aires,
is available. La Ley, a large folio sheet, was a daily paper, published
for a short period only, under the editorship of Senor Enrique
^ La Ley, Buenos Aires, July 2, 1877, p. 1.