FAMILY HIRUNDINIDAE 



7 



Usually Bank Swallows are noted in company with other migrants 

 of the family, less often alone in groups of up to 100 individuals. Dur- 

 ing the winter of 1975-76, a year of exceptional swallow flights in 

 Panama, Ridgely and J. J. Pujals noted about 25 on January 27 at 

 Tocumen, eastern Province of Panama, with thousands of Barn Swal- 

 lows that were definitely not migrating. P. Donahue saw 2 on January 

 2, 1980, at Aguadulce, Code (Eisenmann in litt). 



TACHYCINETA BICOLOR (Vieillot): Tree Swallow; Golondrina Bicolor 



Hirundo bicolor Vieillot, Hist. Nat. Ois. Amer. Sept., vol. 1 (1807), 1808, p. 61, 

 pi. 31. (New York.) 



Medium size; undersur face white; adult, above steel blue; immature, 

 duller, browner above; differs from the Mangrove Swallow in lack of 

 white on upper surface, and larger size. 



Description. — Length 130-140 mm. Male, upper surface, including 

 lesser wing coverts, greenish steel blue; middle wing coverts black, 

 edged with greenish to steel blue; rest of wings and tail dusky; lores 

 black; undersur face white; axillars and underwing coverts brownish 

 gray; edge of wing white. 



Female, similar but usually duller colored above; breast in some 

 washed with brownish gray. 



Immature, upper surface dark mouse gray; usually with breast 

 washed with grayish brown; tertials, and in some individuals, outer 

 upper tail coverts, edged narrowly with white to grayish white. 



Measurements. — Males (10 from Florida, winter) , wing 115.0-125.2 

 (118.4), tail 52.1-58.0 (54.7) , culmen from base 9.0-11.2 ( 10.2) , tarsus 

 12.0-14.4 (13.1) mm. 



Females (10 from Xew York, Florida, winter, spring), wing 108.8- 

 117.0 (112.2), tail 47.8-53.6 (51.5), culmen from base 8.2-10.9 (9.2), 

 tarsus 11.1-13.2 (12.3) mm. 



Winter migrant from the north; irregular, recorded chiefly in the 

 Caribbean coastal lowlands of western Bocas del Toro, and in the Canal 

 Zone. 



The Tree Swallow, an abundant species over a wide range in the 

 north, is common during the winter months south to eastern Honduras. 

 Farther south, along the eastern coast of Central America, it is little 

 known. 



On January 17, 1958, more than 100 Tree Swallows ranged with 

 other swallows over open lands partly flooded from recent rains near 

 Changuinola, Bocas del Toro. I collected a male there on March 4 



