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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 261
regions cited in the original reference. These are the city of Goyaz,
Engenho do Cap Gama, and Cuyaba.
The limited series in the United States National Museum does not
permit the description of new forms among the birds placed under
this name, although one or more are probably represented. It may
be noted that specimens that I secured at Rio Negro, Uruguay (in
worn plumage), are slightly darker above than skins from the Chaco,
while examples from the Chaco in turn seem slightly darker than
those from Brazil.
This form was recorded and secured as follows: Resistencia,
Chaco, July 9, 1920 (adult male secured) ; Las Palmas, Chaco, July
; Riacho Pilaga, For-
19 to 30 (female, July 19, and male, July 30)
mosa, August 7 to 21 (males, August 7 and 9)
; Kilometer 80, west
of Puerto Pinasco, Paraguay, September 15 (adult male) ; Rio
Negro, Uruguay, February 14 to 19 (male and female immature,
February 14, adult male, February 17, and immature male, February
18)
male). This form is recorded by Hellma3^r from Buenos Aires west
; Tapia, Tucuman, April 9 (immature female) and 11 (adult
to Cordoba, Tucuman, and Salta, and north probably to the plains
of Bolivia. Tremoleras has noted it from Montevideo and Canelones
in Uruguay.
Synallaxis f. frontalis has chosen as its haunt dense growths of
weeds or thorny plants and heavy thickets, usually in low areas
shaded by groves. It was especially common in the Chaco and in
the dense thickets along the Rio Negro, in western Uruguay, and
elsewhere was found in smaller numbers. The birds were found
throughout the winter in bands containing from three to eight, ap-
parently family parties still in company from the previous season,
that often fed in growths of heavy grass at the borders of thickets.
When startled they flew a short distance with tilting flight to some
secure cover and at times paused in the open for a few seconds
before disappearing among the branches. Frequently they fed
among the leaves of bushes or dense herbage, usually near the
ground, where they were constantly in motion. When not hopping
about restlessly they peer quickly from side to side, at the twigs
below or the leaves above, flitting the wings and twitching the long
tail. All of these activities were carried on behind a screen of
leaves so that only occasionally did a glimpse of them offer through
some little opening.
They appear much richer in color in life than in the form of a
skin, as the dark browns and grays of their plumage enlivened by
touches of rufous on crown, wings, and tail form a pleasing combi-
nation. The feathers of the throat in life are puffed out so that their
slaty black bases form a shield-shaped patch that appears almost
black.
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