Small, bill rather long, compressed towards the tip, wider at base,
upper mandible somewhat curved, base with about five pairs of rather
long, weak bristles; wing, moderate or rather short, first quill very
short, fourth and fifth, longest and nearly equal; tail, long, with the
feathers graduated, outer shortest; legs, long, slender; toes, rather
short. Colors usually cinereous and black. A genus exclusively American
and containing several species.