Birds
Birds do the Strangest Things
Twenty-two stories of the natural but strange and fascinating behavior of various birds. The text covers ostriches, hummingbirds, kiwis, loons, peacocks, emperor penguins, woodpeckers and much more. The text is somewhat lengthy (approx. 12-20 lines per page), but in fairly large print and at a fairly easy reading level. My children find this book completely fascinating. Part of the "Step-Up" series which includes "Meet George Washington" et al.
Falcons Nest on Skyscrapers
This is a very interesting book (with excellent illustrations) that introduces young children to various falcons living in the United States, some of their remarkable abilities and the story of how some scientists were successful in re-introducing the peregrine falcon in the Eastern United States after they nearly became extinct because of an insect spray called DDT which was overused earlier in the twentieth century.
Birds of the World
This is my favorite of the Dorling Kindersley Eyewitness Handbooks and I would venture to guess that it's probably the best bird handbook you can find. Hundreds of birds, from doves and swallows, to hawks and falcons and tropical birds are included with clear photos, a small map of where they can be found, an icon showing how large they are in comparison to the book, and other basic information about their habitat, migration, etc. Our family has used this guide extensively in identifying and learning more about the substantial variety of birds we find in our own backyard.