Robin Oggins' The Kings and Their Hawks: Falconry in Medieval England is both an excellent place to start for an understanding of medieval hawking and falconry as practiced by English royalty and as a reference work on the subject. I learned quite a bit from this book, particularly on just how big a role this pasttime played as a mark of medieval royal status and the lengths various English kings were willing to go to in its practice.
One important thing I learned was just what the differences were between falcons and hawks:
"The basic physical difference between falcons and hawks lies in the length and shape of their wings and tails. Falcons have narrow pointed wings and narrow tapering tails. The wing beats of the falcon are moderately rapid and regular - the French all falcons ramiers, or rowers, because of the resemblance of their flight to sculling. The hawks used in medieval Europe - goshawks and sparrowhawks - have shorter, rounder wings than falcons, and a relatively longer tail. They have a gliding flight broken at intervals by three or four wing beats, and they frequently soar with wings spread and tail fanned out - hence their French name of voiliers, or sailors.
--As a result of these physical differences, the hunting styles of falcons and hawks vary considerably. Falcons typically attack by diving or "stooping" from a considerable height. If the stoop is successful, the falcon hits its prey with tremendous speed: in the case of the peregrine, this may reach over two hundred miles per hour. The prey is struck with a blow from the talons and the first blow alone is often fatal....
--Hawks, on the other hand, usually approach their quarry at a low altitude and fly it down with a quick burst of speed. 'In fact, the hawk is called accipiter, and also astur from its natural adroitness [astus], because it almost always stays hidden and flies close to the ground, contrary to the manner of falcons, and when it takes a bird, it seizes it [accipit] from below as if whirling around on itself.' Rather than hitting the prey and returning to pick it up, as falcons do, hawks grab or clutch their prey, usually killing by driving their talons into the victim's body and holding on until the creature is dead, though they may also kill with a stroke of the beak. While both falcons and hawks have strong feet, the feet of hawks are particularly well developed for holding and killing."
My only real quibble with the book is that too often Oggins sticks to strict references to facts gleaned from medieval source materials without attempting to step back and provide a broader picture of the times. The occasional anecdote is often far more illuminating than the at times seemingly endless recitation of the costs of birds in pounds, shillings and pence drawn from royal ledgers.
Recommended for anyone with an interest in hawking and falconry as it was practiced in the Middle Ages and its role as a defining mark of status amongst royalty.