Cornell Lab of Ornithology

Cornell Lab of Ornithology has a very nice online bird guide with information, photographs, and sounds of many American birds. They also have a page with the birdhouse requirements of various birds. Western Screech Owls, Gila Woodpeckers, and Ash-Throated Flycatchers have all nested in birdhouses in my yard here in Tucson, while Roadrunners and Mourning Doves have nested in bird baskets (large, woven baskets placed in a tree).