The Sibley Guide to Trees (Sibley Guides)

The Sibley Guide to Birds, 2nd Edition (Sibley Guides)

The Sibley Field Guide to Birds of Eastern North America: Second Edition (Sibley Guides)

Sibley's Birding Basics: How to Identify Birds, Using the Clues in Feathers, Habitats, Behaviors, and Sounds (Sibley Guides)

Sibley Birds West: Field Guide to Birds of Western North America

Bark: A Field Guide to Trees of the Northeast

Audubon Society Field Guide to North American Trees: Eastern Region

What It's Like to Be a Bird: From Flying to Nesting, Eating to Singing--What Birds Are Doing, and Why (Sibley Guides)

National Wildlife Federation Field Guide to Trees of North America

Sibley Backyard Birding Flashcards: 100 Common Birds of Eastern and Western North America (Sibley Birds)

Winter Tree Finder: A Manual for Identifying Deciduous Trees in Winter (Eastern US) (Nature Study Guides)