I 



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 pri- 

 maries 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, 

 54207—26 11 



