LINES OF MIGRATORY FLIGHT 149 



paratively few of these pass beyond the tropics. 

 There are some however that go south regularly to 

 the South Temperate Zone, and among those that 

 perform this extended flight are a few birds of com- 

 paratively small size. The barn swallow migrates in 

 part to Paraguay and Argentina, and may be found 

 in the southern spring hawking about with flocks of 

 native swallows, some of which later may retreat to 

 Patagonia to breed. The bobolink is more worthy of 

 mention as, though the barn swallow ranges from 

 the West Indies southward in winter, the bobolink 

 withdraws entirely into Brazil and the Chaco. 



The cliff" swallow, the olive-backed thrush, the 

 yellow-billed cuckoo, the nighthawk, and Swainson's 

 hawk are regular, though not abundant, arrivals as 

 far as northern i\rgentina, while along the coasts of 

 the Province of Buenos Aires we may expect para- 

 sitic and long-tailed jaegers, and Cabot's, royal, and 

 arctic terns. The bulk of North American migrants 

 here, however, is composed of shore-birds, of which 

 some species, as the golden plover, the upland 

 plover, Baird's, white-rumped, buff-breasted, and 

 pectoral sandpipers, the Hudsonian godwit, and for- 

 merly the Eskimo curlew, find in the pampas and in 

 Patagonia their winter metropolis. A few individuals 

 of these northern species arrive in the south in 

 July and August, but the main southward flight 

 occurs from September to October. In other words 



