Birds of America
By John James Audubon, F. R. SS. L. & E.
VOLUME I.
GENUS VIII.--NAUCLERUS, Vig. SWALLOW-TAILED HAWK.
Bill short, wide at the base, much compressed toward the end; upper
mandible with the dorsal line decurved from the base, the sides slightly convex,
the edges with a slight festoon, the tip narrow and acute; lower mandible with
the angle very wide, the dorsal line straightish, the tip rounded and declinate.
Nostrils round, with a central papilla. Head rather large, roundish, flattened;
neck short; body compact. Feet short; tarsus very short, thick, scaly all
round; toes scutellate above, scabrous beneath, with pointed papillae; claws
rather long, curved, acuminate. Plumage blended, glossy. Wings extremely long,
pointed, the third quill longest; secondaries short. Tail extremely long, very
deeply forked.