32 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



ridge near Cerro Azul he saw a full grown (flying) juvenal being fed 

 by an adult; by this period many birds were in small flocks. 



NOTIOCHELIDON CYANOLEUCA (Vieillot): Blue-and-white Swallow, 

 Golondrina Barranquera Azul 



Small; undersurface from throat to abdomen white; above, dark 

 steel blue. 



Description. — Length 110-125 mm. Adult (sexes alike), tail mod- 

 erately forked; dorsal surface, including the scapulars, iridescent dark 

 steel blue; lores and space immediately behind eye black; wings and tail 

 dull black; undersurface with throat, breast, and abdomen white; up- 

 per sides black; undertail coverts black (nominate race cyanoleuca) , or 

 black and white (patagonica) . 



Immature, upper surface dull sooty brown on crown and back; else- 

 where, including wings and tail, dull brown; throat, band across breast, 

 and sides wood brown; throat, breast, and abdomen white; undertail 

 coverts dull brown, or mixed dull brown and white. 



The dark (or partly dark) undertail coverts distinguish this species 

 in life from the Mangrove Swallow, which also is small, with clear 

 white undersurface, but with this color including also all of the under- 

 tail coverts. In addition, the Mangrove Swallow has a white rump and 

 a short, narrow white supraloral, lacking in cyanoleuca. 



Two geographic races are found in Panama. The nominate form 

 breeds in Panama, and in South America, from Colombia to southern 

 Brazil, Uruguay, and northern Argentina. The more southern breed- 

 ing form, N. c. patagonica, is recorded as nesting from the mountains 

 in northern Argentina to northern Tierra del Fuego. In the period of 

 southern winter, patagonica moves northward, and with it move the 

 more southern populations of nominate cyanoleuca. It is probable that 

 the flocks recorded irregularly in Panama during the breeding season 

 comprise migrants of both races. 



NOTIOCHELIDON CYANOLEUCA CYANOLEUCA (Vieillot) 



Hirundo cyanoleuca Vieillot, Nouv. Diet. Hist. Nat., nouv. ed., vol. 14, September 

 1817, p. 509. (Paraguay.) 



Characters. — Adult, with all of the undertail coverts black; under- 

 wing coverts dark to blackish grayish brown. 



Immature, undertail coverts dark brown, in some individuals tipped 

 lightly with white; underwing coverts dark brown. 



An adult female, collected at 1350 m along the Rio Chiriqui Viejo, 



