Family II. FALCONINAE. FALCONINE BIRDS.
GENUS X. ASTUR, Cuv. HAWK

Bill short, robust; its upper outline sloping, and nearly straight at the base, then decurved; cere short, bare above; edge of upper mandible with a festoon, succeeded by a broad sinus. Nostrils elliptical. Feet of moderate length; tarsi moderate or slender, feathered at least one-third of their length, broadly scutellate before and behind; first and second toes strongest and equal, third much longer, and connected at the base by a web with the fourth, which is shortest; claws long, well curved, acuminate. Wings very broad, of moderate length, much rounded, fourth and fifth quills longest, first much shorter, outer four abruptly cut out on the inner web. Tail long, much exceeding the wings, rounded.

Those of more slender form, with proportionally longer tails and tarsi, are separated by many authors to form a group, to which the names of Accipiter and Nisus are given.