Great FREE App for iPhone,iPad and IPod. Peterson bird guide, range maps, bird sounds, and more. Upload and use during the Great Backyard Bird Count.
Review from the Birder's library:
When A Field Guide to the Birds was published in 1934, I doubt that anyone, including the author, even considered that it would still be around over 75 years later. But even though it has gone through many changes, Roger Tory Peterson’s field guide is still here and still relevant. And now it has made the transition into the digital realm as the Peterson Birds of North America app.