Birds of North America (E-book)

Birds of North America is the result of the combined efforts of the American Ornithologists' Union, the Cornell Lab of Ornithology, and the Academy of Natural Sciences

The contents are updated frequently, with contributions from researchers, citizen scientists, and designated reviewers and editors.

In addition, BNA Online contains image and video galleries showing plumages, behaviors, habitat, nests and eggs, and more. And most online BNA accounts now feature recordings of the songs and calls of their species, recordings selected from the extensive collection of Cornell's Macaulay Library