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

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BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 157
species. At times the chattering of these active flocks reminded me
of the twittering of swallows.
One adult femal^ taken September 6 is still in worn breeding
plumage, another has replaced a part of the plumage of breast and
back. Both have worn rectrices. An immature female in full plum-
age was taken September 21, while one shot November 7 has lighter
tips on the feathers of the dorsal surface partly worn away. Two
more females, shot March 4 and 5, are in full prenuptial molt, a
change that has involved the upper tail coverts so that these are as
much brown as white and, though in migration, have the outer primaries
still not quite grown. A complete molt seems to take place in
February and March.
CALIDRIS CANUTUS RUFUS (Wilson)
Tringa rufa Wilson, Amer. Ornith., vol. 7, 1813, p. 43, pi. 57, fig. .l.
(Shores of Middle Atlantic States.)
On November 7, 1920, a sanderling in winter plumage was killed at
a pool of fresh water in the dunes 24 kilometers south of Cape San
Antonio on the coast of Buenos Aires. The bird was feeding in
company with white-rumped sandpipers.
TRYNGITES SUBRUFICOLLIS (Vieillot)
Tringa subriificoUis Vieillot, Nouv. Diet. Hist. Nat., vol. 34, 1819, p. 465.
( Paraguay.
In addition to the generic characters usually cited, Tryngites may
be recognized by the conformation of the nostril, wliich is elongate
and has a median lobe projecting from the upper margin so as to
lend the appearance of a median division. In addition, a single
line of tiny plumes extends forward from the frontal antiae along
the lower side of the nasal slit to a point anterior to the dividing
lobe. These feathers ma}'^ be worn away in some specimens but are
present in the majority. Aechmorhi/nchus has an approach to
this condition in a slightly swollen flap on the upper margin of the
nostril, but this extends for the full lenglh of the slit, and there
are (in the four specimens seen) no feathers below the nostril.
Prosohonia I have not seen. The nasal lobe in Aechmorhynchus
is suggestive of the condition found in the plovers.
The buff-breasted sandpiper was first recorded in fall when an
adult male was found on September 21, 1920, standing a little apart
from other sandpipers on the open shore of a lagoon at Kilometer
80, west of Puerto Pinasco, Paraguay. On November 13 another
was seen with other sandpipers on the tidal flats below Lavalle,
Buenos Aires. No others were noted until, from March 3 to 8,
1921, a few were encountered in northward migration near Guamini,
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