Fossil and Recent Avifaunas and the Interamerican Interchange

Abstract

Ornithologists have long known that important interchanges took place in the Cenozoic between the North and South American avifaunas (von Ihering, 1927; Lönnberg, 1927). The debate about what taxa were involved and what direction they migrated has not often been resolved satisfactorily, however, because Recent birds give clues that can be interpreted in different ways by different people and because fossil birds have frequently been dismissed since they apparently offer such insignificant evidence.