158 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



Buenos Aires, where they arrived from regions farther south, tarried 

 for a time, and then continued their north^yard flioht. 



The birds ranged in small flocks that occasionally fed with other 

 sandpipers in the shallows or on muddy shores, but more frequently 

 worked a short distance farther back on alkaline barrens where 

 the surface was damp from the salt in the soil, but there was no 

 standing water, and where vegetation was reduced to stumps of 

 herbaceous growth that had been killed by concentration of alkali. 

 They walked nervously, picking at the ground, and were active and 

 quick in all their movements, constantly in motion, occasionally 

 running a few feet to join others that had passed on ahead. When 

 in the air or on the ground they are distinctly buff in color, with 

 a glimpse of the marbled underAving surface as they rise or pass, 

 and a flash of the gray tail with its darker markings as they alight. 

 On the ground in profile, they show a long neck and long legs, 

 while the short bill is suggestive of that of a pigeon. The neck 

 is drawn in during flight. As they rise they may give a Ioav call 

 that resembles chump^ somewhat robinlike in tone; a second call 

 note is a low trilled fr-r-r-reet. The species is to be confused in 

 the field Avith no other shore bird. 



An adult male shot September 21 had the bill black, shading to 

 deep olive gray at the base of the maxilla ; iris cameo brown ; tarsus 

 olive ocher, changing to dark olive buff on the toes, with a shading 

 of the same color on the crus and the tarsal joint; nails black. 

 Another male taken March 3 had the tarsus yellow ocher, shading 

 to honey yellow on the toes. 



A male shot September 21 was in worn breeding plumage. Others, 

 secured March 3 and 5 that were completing the molt, had the outer 

 primaries not quite grown and new contour feathers still develop- 

 ing. Specimens secured in March were extremely fat and difficult 

 to prepare. 



MICROPALAMA HIMANTOPUS (Bonaparte) 



Tringa himantopus Bonaparte, Ann. Lye. Nat. Hist. New York, vol. 2, 

 1826, p. 157. (Long Branch, New Jersey.) 



The stilt sandpiper was encountered only in the Chaco, west of 

 Puerto Pinasco, Paraguay, though it has been said that it is common 

 in some parts of the Province of Buenos Aires in winter. At Kilo- 

 meter 80, on September 20, 1920, the first arrivals, a flock of a dozen, 

 were recorded at the border of a lagoon; as I watched thev rose 

 suddenly to whirl rapidly away to the southward. On the follow- 

 ing day about 20 were seen and an adult female was taken. At 

 Kilometer 170 on September 24 a small flock passed down the 

 nearly dry channel of an alkaline stream known as the Riacho 

 Salado, while at Laguna Wall (Kilometer 200) about 30 were seen 

 September 24. and 40 on the day following. The birds were found 



