Birding is the fastest growing wildlife-related activity in the U.S., and even conservative estimates put the current number of U.S. birders at 50 million. According to the New York Times, some authorities predict that by 2050 there will be more than 100 million�and the National Geographic Field Guide to the Birds of North America will be the essential reference for field identification and the cornerstone of any birder's library. This is the ultimate, indispensable bird field guide�comprehensive, authoritative, portable, sturdy, and easier than ever to use. * 504 pages with 4,000 color illustrations and maps * Softcover * 5'' x 8'' * � 2006