Aspects of Evolution in the Parrot Genus Agapornis

Abstract

Agapornis, an African genus of parrots allied to Loriculus of Asia, has usually been classified in nine species. Their geographical, altitudinal and ecological ranges are described and their temperature relations are worked out. There is a general agreement with Bergmann's rule. Only two of the Agapornids appear to be in any respect ecologically specialized: to A. swinderniana, the only one confined to tropical evergreen forest, the seeds of figs may be an essential food; and A. pullaria is more or less completely dependent on the nests of arboreal insects for nesting‐sites. The other seven Agapornids are birds of dry country with a wide range of food and are indiscriminate hole‐nesters. All nine birds are practically allopatric. The four closely allied birds in East Africa, which produce fertile hybrids very freely in captivity, seem nowhere actually to meet in nature. Certain vegetation types, especially Brachystegia‐Isoberlinia woodland, appear to be an effective barrier, for reasons not clear.