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

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262 BULLETIN 133, UNITED STATES NATIONAL MUSEUM They have a variety of sputtering, scolding calls that they utter on occasion of alarm or interest, and in the spring and summer sing a pleasing little song. A male taken September 15 at Puerto Pinasco. Paraguay, was approaching breeding condition, while near Rio Negro, Uruguay, fully grown young were common during the middle of February. Young in ju venal plumage lack the rufous crown cap of adults but gain it at the post-juvenal molt. In first dress they are browner both above and below and have the wing coverts less bright than after the first molt. In an adult male the maxilla was dull black; mandible gray number 6; iris pecan brown; tarsus and toes, grayish olive. Another differed in that the maxilla and tip of the mandible were blackish slate and the iris cinnamon rufous. SYNALLAXIS ALBESCENS ALBESCENS Temminck Sijnallaxis albescens Temminck, Nouv. Rec. Planch. Col. Ois., vol. 3, 1838, pi. 227, fig. 2. (Province of Sao Paulo, Brazil.'') Birds of this species were recorded at the following points: Re- sistencia, Chaco, July 10, 1920 (immature female taken) ; Las Palmas, Chaco, July 16 to 31 (males, July 17 and 31, females on July 16, 17, and 28) ; Formosa, Formosa, August 24; Puerto Pinasco, Paraguay, September 3 (adult male) ; Victorica, Pampa, December 24 to 29 (males on December 24, 27, and 29, female, December 29). The specimens secured are allocated to the typical form without direct comparison with skins from southern Brazil. The small series from Victorica, Pampa, in somewhat worn breeding plumage is slightly grayer than skins secured during winter in the Chaco, but seems otherwise similar. The remainder of the skins taken are quite uniform. Specimens in fresh winter plumage have the rufous color of the crown slightly obscured by brownish tips. During the winter months, in the Chaco, this spine tail was abundant in saw grass and bunch grass at the borders of thickets, or in little openings among scattered trees and bushes on the savan- nas. On sharp frosty mornings comparatively few were encountered until about 11, when as the day became warmer these small birds appeared in numbers in brushy pastures where none had been visible two hours before. They flew out with quick, tilting flight to new cover or dodged in and out among the clumps of grass or low branches with quick scolding notes, but seldom paused to perch in the open. Their choice of haunt in fairly open savanna regions was in decided contrast to the habitat of Synallaxis a. frontalis that frequented the spiny growths of caraguata amid denser, darker ^ Designated by Berlepscb and Hartert, Nov. Zool., vol. 9, April, 1902, p. 59.

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.

262 BULLETIN 133, UNITED STATES NATIONAL MUSEUM<br />

They have a variety of sputtering, scolding calls that they utter on<br />

occa<strong>si</strong>on of alarm or interest, and in the spring and summer <strong>si</strong>ng a<br />

plea<strong>si</strong>ng little song. A male taken September 15 at Puerto Pinasco.<br />

Paraguay, was approaching breeding condition, while near Rio<br />

Negro, Uruguay, fully grown young were common during the middle<br />

of February. Young in ju venal plumage lack the rufous crown cap<br />

of adults but gain it at the post-juvenal molt. In first dress they are<br />

browner both above and below and have the wing coverts less bright<br />

than after the first molt. In an adult male the maxilla was dull<br />

black; mandible gray number 6; iris pecan brown; tarsus and toes,<br />

grayish olive. Another differed in that the maxilla and tip of the<br />

mandible were blackish slate and the iris cinnamon rufous.<br />

SYNALLAXIS ALBESCENS ALBESCENS Temminck<br />

Sijnallaxis albescens Temminck, Nouv. Rec. Planch. Col. Ois., vol. 3, 1838,<br />

pi. 227, fig. 2. (Province of Sao Paulo, Brazil.'')<br />

Birds of this species were recorded at the following points: Re-<br />

<strong>si</strong>stencia, Chaco, July 10, 1920 (immature female taken) ; Las Palmas,<br />

Chaco, July 16 to 31 (males, July 17 and 31, females on July<br />

16, 17, and 28) ; Formosa, Formosa, August 24; Puerto Pinasco,<br />

Paraguay, September 3 (adult male) ; Victorica, Pampa, December<br />

24 to 29 (males on December 24, 27, and 29, female, December 29).<br />

The specimens secured are allocated to the typical form without<br />

direct comparison with skins from southern Brazil. The small<br />

series from Victorica, Pampa, in somewhat worn breeding plumage<br />

is slightly grayer than skins secured during winter in the Chaco,<br />

but seems otherwise <strong>si</strong>milar. The remainder of the skins taken are<br />

quite uniform. Specimens in fresh winter plumage have the rufous<br />

color of the crown slightly obscured by brownish tips.<br />

During the winter months, in the Chaco, this spine tail was<br />

abundant in saw grass and bunch grass at the borders of thickets,<br />

or in little openings among scattered trees and bushes on the savan-<br />

nas. On sharp frosty mornings comparatively few were encountered<br />

until about 11, when as the day became warmer these small birds<br />

appeared in numbers in brushy pastures where none had been vi<strong>si</strong>ble<br />

two hours before. They flew out with quick, tilting flight to new<br />

cover or dodged in and out among the clumps of grass or low<br />

branches with quick scolding notes, but seldom paused to perch in<br />

the open. Their choice of haunt in fairly open savanna regions<br />

was in decided contrast to the habitat of Synallaxis a. frontalis that<br />

frequented the spiny growths of caraguata amid denser, darker<br />

^ De<strong>si</strong>gnated by Berlepscb and Hartert, Nov. Zool., vol. 9, April, 1902, p. 59.

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