Opening the field guide
Astur cooperii
A crow-sized woodland hawk with a large, blocky head that projects well ahead of the wings in flight.

Big, block-shaped head that pushes well past the leading edge of the wings when gliding
Tail tip rounded, with a broad white terminal band
Dark cap contrasting against a paler nape, giving a 'capped' look
Sturdy legs and a body roughly crow-sized
Woodlands, forest edges, leafy suburbs, and city parks across much of North America.
Bursts from cover with a few stiff flaps and a long glide, hunting birds around woodland edges and feeders. Increasingly common in towns and suburbs.
Sharp-shinned hawks are smaller with a small head that barely projects, a squared tail tip, and a hooded rather than capped head. Sizes overlap — a large female sharp-shinned can approach a small male Cooper's.
Watch from a distance and never linger near a nest. If a hawk is hunting a feeder, pausing feeding for a week or two is the usual advice rather than intervening.
No danger to people, though a bird defending a nest may stoop close. Injured raptors should be handled only by a licensed rehabilitator.
Populations recovered strongly after the decline of DDT-era pesticides and the species has adapted well to suburban life.
Sources are linked below. Field marks vary with age, sex, season, region, light, and viewing distance.