Birds of America
By John James Audubon, F. R. SS. L. & E.
GENUS II.--LAGOPUS. PTARMIGAN
Bill short, robust; upper mandible with its dorsal outline decurved, the
ridge indistinct and rounded, the sides convex, the edges overlapping, the tip
declinate, thin-edged, rounded; lower mandible with the angle of moderate length
and rounded, the dorsal line convex, the sides rounded, the edges a little
inclinate, the tip rounded; nasal sinuses large and covered with feathers,
leaving the ridge narrow between them. Nostrils basal, roundish, concealed by
the feathers. Head small, ovate; neck rather long; body bulky. Feet rather
short, stout; tarsus feathered, as are the toes, which have two or three
terminal scutella; hind toe extremely short, lateral toes equal. Claws slightly
arched, depressed, thin-edged, rounded. Plumage full and compact, the feathers
rounded. Wings short, convex, the primaries strong, narrow, tapering, the third
longest, the fourth and second little shorter. Tail short, nearly even, of more
than twelve broad feathers.