Vol. 46, pp. 187-190 October 26, 1933 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASlfrlNdlTON. ci . CRITICAL NOTES ON AMERICAN VULTURES. BY HERBERT FRIEDMANN.' The following observations and notes were made while study-ing the Cathartidae in connection with the continuation of Ridgway's unfinished work, The Birds of North and Middle America. 1. The Genus Coragyps. Current literature treats with this monotypic genus as comprising two races, the North American black vulture, C. atratus atratus (Bechstein) and the South American form, C. atratus foetens (Lichtenstein) . The latter subspecies is said to be smaller, but otherwise not different, from the nominate race. However, there has been considerable difference of opinion among investigators as to whether or not the two forms were constant in their differences. Thus, Todd (Ann. Carnegie Mus., xiv, 1922, 142) treated the black vulture binomially; Wetmore (Bull. 133, U. S. Nat. Mus., 1926, 90) called his South American birds C. atratus foetens, but wrote that in a limited series he was unable to find any sharply trenchant difference between northern and southern birds. Through the kindness of Mr. John T. Zimmer, of the American Museum of Natural History, I have been able to borrow a series of South American birds to amplify the material in Washington. All in all I have seen 10 specimens of foetens (from Argentina, Chile, Ecuador, and Brazil) and twice that many of typical atratus. My findings are as follows: South American birds have wings ranging from 412-432 mm. (one Chilean speci-men 405 mm.); North American birds measure, in this dimension, from 415-454 mm. The average of the South American birds is 421 mm., that of the North American series 432.8 mm. It may be seen that although North American birds may achieve considerably greater proportions than South American specimens, yet, practically all (8 out of 10) of the latter group may be matched by North American birds. In other words, if we accept size as a valid criterion of race, we can identify none of the South American birds by this means, and only the larger examples from North America. Not only are the variational limits of foetens almost wholly iPublished by permission of the Secretary of the Smithsonian Institution. 39— Peoc. Biol. Soc. Wash., Vol. 46, 1933. (187)
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