FAMILY IlIRUXDINIDAE 



13 



the last day, usually feeding with larger numbers of Blue-and-white 

 Swallows. Then, up to 80 were seen feeding over open hillsides near 

 the Volcan Lakes, western Chiriqui, on January 13-14, 1977. All field 

 marks were noted with care, including the white patches on the sides of 

 the rump, the white vent, and the white on the sides of the head (Tou- 

 can, vol. 4, no. 2, 1977, pp. 6-7) . 



HIRUNDO RUSTICA ERYTHROGASTER Boddaert: Barn Swallow, 

 Golondrina Tijereta 



Hirundo crythrogastcr Boddaert, Table Planch. Enlum., 1783, p. 45. (French 

 Guiana.) 



Size medium; adult, in full plumage, with long, deeply forked tail 

 (the lateral feathers often lost during the winter molt, so that this char- 

 acter is not evident; identified then by the steel blue back and rump) . 



Descripion. — Length 149-186 mm. Adult male, forehead chestnut; 

 rest of upper surface steel blue, including edging on tertials and mid- 

 dle wing coverts; wings and tail dusky; inner webs of rectrices (ex- 

 cept central pair) with a white spot; malar area, chin, throat, and fore- 

 neck to upper margin of chest cinnamon-rufous; steel blue color or 

 lower side of neck extending over the side of the chest, in some the 

 two sides joined; rest of undersurface, including sides, axillars, under- 

 wing coverts and undertail coverts, pale cinnamon-rufous. 



Adult female, usually similar, but in some the undersurface paler. 



Immature, much duller colored; forehead dull white to buff; crown 

 and hindneck dull brown to sooty black; undersurface duller, browner; 

 in some, breast, sides, and abdomen white. 



Measurements. — Male (10 from eastern and western United States, 

 British Columbia, and Alaska), wing 114.3-123.6 (119.9), tail 71.2- 

 92.8 (82.9), culmen from base 9.4-11.5 (10.7), tarsus 11.1-12.0 

 (11.6) mm. 



Females (10 from eastern and western United States, British Co- 

 lumbia, and Alaska), wing 109.1-119.2 (115.7), tail 69.7-83.3 (76.3), 

 culmen from base 10.0-11.9 (10.9), tarsus 11.2-12.2 (11.6) mm. 



Migrant from the north, abundant; common winter resident espe- 

 cially on the more open Pacific slope from early September through 

 April, with many in passage to and from wintering grounds in South 

 America. A few remain through the period of northern summer. Most 

 common in the lowlands but ranging also across the higher levels. 



Migrant flocks en route to and from South America move regularly 

 over the sea along the Caribbean coast, and also are seen crossing the 



