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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 263
thickets. In a way the areas inhabited by the two are reflected in
their tone of plumage, the bird of the grass ckimps being paler than
the one that frequents the darker forest border. S. a. albescens was
gregarious, so that a number w^ere found together, often in mixed
flocks with little groups of finches. It w^as not unusual to find them
in tall grass in wet localities rather distant from protecting shrub-
bery.
At Victorica, Pampa, albescens was of different habit, as here it frequented
the bushes and low trees that formed a heavy ground cover
in the open, scrubby forest. Toward the end of December the birds
had completed breeding and were encountered in little parties that
comprised adults and young. They were social and searched rather
quietly through the limbs, often in close proximity to one another.
Though quiet and deliberate in movement they clambered rather
actively through the thorny twigs, always under cover. They ranged
here from 1 to 10 meters from the earth, and were not found feeding
on the ground. This difference in habit from what I had observed
in the Chaco led me to suppose that the birds from Pampa were dif-
ferent, but such does not seem to be the case.
In a female, taken July 10, the maxilla was blackish brown number
1
; mandible mineral gray ; iris honey yellow around pupillar open-
ing, becoming lighter toward outer margin; tarsus and toes deep
grayish olive.
SYNALLAXIS ALBILORA Pelzcln
Synallaxis alMora Pelzeln, Sitzungsb. Math.-Nat. CI. Kais. Akad. Wiss.
(Wien), vol. 20, 1856, p. 160. (Cuyaba.)
Near Kilometer 80, west of Puerto Pinasco, Paraguay, on September
16, 1920, I found one of these birds in heavy, low forest
perched on a stick nest as large as a hat, while its mate hopped about
in heavy brush near by. Attention was drawn to the pair by the
curious song of the bird at the nest tas pit taho we^ a peculiar succession
of notes with rather slow nasal cadence. Both birds were
slow and deliberate in their actions.
In the adult female the maxilla was black ; mandible gray number
6 ; iris liver brown ; tarsus neutral gray and toes storm gray. These
birds may represent a new form, as the skin preserved is somewhat
paler, less rufescent below than the average of a small series in the
American Museum of Natural History from Matto Grosso, Brazil.
The species is known from Brazil and Bolivia, but does not appear
to have been recorded previously from Paraguay. Measurements
of the bird secured are as follows: Wing, 58; tail, 74.5; culmen from
base, 12.8; tarsus, 21.3 mm.