Bulletins. 50. Birds of North and Middle America, descriptive catalog of higher groups, genera, species, and subspecies of birds known to occur in North America, from Arctic lands to Isthmus of Panama, West Indies and other islands of Caribbean Sea, and Galápagos Archipelago: pt. 11, family Cathartidae, American vultures, family Accipitridae, hawks, eagles, kites, harriers, and Old World vultures, family Pandionidae, ospreys, family Falconidae, falcons and caracaras; by Herbert Freidmann.