More or less cosmopolitan groups like herons, Falconidae, Anseres, Columbae, &c., and circumtropical families like Parridae, Trogonidae,.
Falconidae, cosmopolitan, since the Eocene.
Thus he separates the birds of prey into three great groups - (I) the ordinary Diurnal forms, including the Falconidae and Vulturidae of the systematist of his time; but distinguishing the American Vultures from those of the Old World; (2) Gypogeranus, the secretary-bird; and (3) the owls (q.v.).
Gypo - Falconidae.
In some external characters the lammergeyer is intermediate between the families Vulturidae and Falconidae, and the opinion of systematists has from time to time varied as to its proper position.