"Keith L. Bildstein has studied migrating raptors on four continents and directs the conservation science program at Hawk Mountain Sanctuary, Pennsylvania, the

Identifying hawks in flight is a tricky business. Across North America, tens of thousands of people gather every spring and fall at more than one thousand known

" ... This book changes field guide design to make you a better birder ... The most comprehensive guide : 640 stunning scenes created from 10,000 of the author'