To make sure that your identifications are correct it's helpful to have several bird
guides against which to cross-check your ideas. Listed here are some of the more popular
guides (good for at least our geographical region):
The Audubon Society
Field Guide to North American Birds - Eastern Region
National Geographic Society
Field Guide to the Birds of North America
Donald and Lillian Stokes
Field Guide to the Birds of North America - Eastern Region
Peterson Field Guide Series
Eastern Birds of North America
Golden Publishing
Eastern Birds - A Guide to Field Identification of North American Species