That the red-tailed hawk is a natural enemy to be reckoned with throughout the racer's extensive range was demonstrated by the analysis of contents of 116 stomachs from localities well scattered over the United States and Canada. Among the 152 vertebrate prey items represented there were three racers: a juvenile _C. c. constrictor_ from Stag Lake, New Jersey, October 16, 1927; a _C. c. mormon_ from Weiser, Idaho, April 11, 1930, and a _C. c. stejnegerianus_ from San Roman, Cameron County, Texas, in the spring of 1938. Because of the widely scattered geographical origin of these stomachs, a remarkably large number of species of prey were represented, and no one species predominated. Small mammals of the genera _Sylvilagus_, _Spermophilus_, and _Thomomys_ comprised the most important component of the food; the only other reptile so well represented as the racer was the common garter snake (_Thamnophis sirtalis_) which likewise had three occurrences. In June and July, 1954, a nest of broad-winged hawks (_Buteo platypterus_) on the Reservation yielded 71 prey items of which seven were blue racers. At least 19 species of prey were represented, although specific determinations were not possible in some instances. The prairie vole with eight records was the most frequent prey, and the racer and cardinal (nestlings) each had seven, while all other species were represented by fewer occurrences. Six of the racers were first-year young but the remaining one was thought to be an undersized second-year individual. Although an adult racer, especially a large one, would probably be an adversary too powerful to be killed and eaten by a broad-winged hawk, this hawk is perhaps one of the more important natural enemies of the first-year young in the eastern United States. Further records of predation on racers by raptors were obtained from the U. S. Fish and Wildlife Service files through the kindness of Dr. Wm. H. Stickel. There were three records of such predation by red-shouldered hawks (_Buteo lineatus_) from Lunenberg, Massachusetts, May 1, 1896; Portland, Maine, March 16, 1906; and 65 miles northeast of Sarasota, Florida, June 10, 1918. There were two records of predation by broad-winged hawks from Catlettsburg, Kentucky, July 26, 1910, and Portland, Connecticut, May 18, 1912. There were four records of predation by marsh hawks on racers--Peck's Island, Maine, September 18, 1903; Edgartown, Massachusetts, April 12, 1912; West [Tisbury?], Massachusetts, July 31, 1912; and Okanagan Landing, British Columbia, June 5, 1918. A sparrow hawk (_Falco sparverius_) from De Ranch, Wyoming, May 27, 1910, had eaten a racer, as had a barn owl (_Tyto alba_), from Franklin County, Kansas, November 16, 1922, and a crow (_Corvus brachyrhynchos_, nestling) from Onaga, Kansas, May 16, 1914.