SYSTEMATIC NOTES CONCERNED WITH THE 

 AVIFAUNA OF PANAMA 



By ALEXANDER WETMORE 



Research Associate 

 Smithsonian Institution 



The observations and descriptions included in the following pages 

 have come to attention during detailed studies of the birds of the 

 Isthmus of Panama and their comparison with forms from other 

 tropical areas. They are based in the main on the collections of the 

 United States National Museum, with addition of specimens seen 

 in the course of work at other institutions. 



I. GEOGRAPHIC VARIATION IN THE BLACK VULTURE, 

 CORAGYPS ATRATUS (BECHSTEIN) 



Opinion on recognition of races in the black vulture has varied 

 from treatment of the entire population as undivided throughout the 

 vast range, from southern United States south through Central 

 America and South America to southern Chile and Argentina, and 

 recognition of two races, one northern and one tropical, based on 

 difference in size. The latter view has been abandoned currently in 

 the main since a study by Friedmann (1933, pp. 187-188) in which 

 he compared average size of North American birds with a small 

 series from southern South America to find that the wing measure- 

 ments appeared too similar to warrant separation. In the course of 

 studies during recent years I have had opportunity to examine ap- 

 proximately 130 black vultures in various collections in the United 

 States and to assemble a series of measurements that verify the 

 findings of Brodkorb (1944, pp. 115-121) that three size groups are 

 present, a smaller population in the tropical area and two larger ones 

 in the temperate regions to the north and south on either side. 

 Brodkorb was uncertain as to the nomenclature to be used since he 

 could not distinguish between the two larger groups, which he there- 

 fore treated under one name. The extensive material that I have 

 seen has justified the recognition of 3 races, as follows: 



CORAGYPS ATRATUS ATRATUS (Bechstein) 



Vultur atratus Bechstein, in John Latham's AUg. Uebers. Vogel, Bd. i, Anh., 

 1793, p. 655. (Florida.) 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 145, NO. 1 



