The Patuxent Bird Identification Infocenter provides general information on
each species, including identification tips, photographs and song clips
(for many species), basic life history information, and maps of the
distribution in North America in the breeding season (from the North American
Breeding Bird Survey) and in early winter (from the Christmas Bird Count).
Information on population trends for each species from the North American
Breeding Bird Survey can also be accessed by a hypertext link from the
species' Identification Tips.