Whether soaring or perched, diurnal birds of prey often present challenging identification problems for the bird enthusiast. Variable plumage, color morphs, and unique individual characteristics are just some of the factors bird watchers must consider when identifying the different species. In this authoritative reference, two of the world's top experts on raptors provide an essential guide to the variations in the species, allowing for easier recognition of key identification points. All the distinguishing marks described have been exhaustively tested in a wide range of field conditions...