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,
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.