Birders trained to ID birds by their plumage are typically mystified by their first hawk-watching experience—from a distance, raptors may be near impossible to tell apart. Focus on the traits you can make out: size, shape, overall color or tone, and the manner and cadence of the bird’s wing beats. My advice: Don’t be intimidated, but don’t be dismissive either. If you want to play in the hawkwatching arena, you’re going to have to rethink your concept of a field mark. Distant IDs aren’t made instantly—they’re built, by piecing together multiple clues that favor one species over another. Size and Shape Most birds of prey fall into four major categories. (Northern Harrier, Osprey, and kites are a few exceptions.) These are the core attributes for each: Buteos are the large, broad-winged, short-tailed lugs with spare and labored wing beats. Accipiters are small, narrow-tailed forest dwellers with short, rapid, bursting flaps, punctuated by a...