Birds of America
By John James Audubon, F. R. SS. L. & E.
VOLUME IV.
GENUS III.--AGELAIUS, Swains. MARSH-BLACKBIRD.
Bill shorter than the head, stout, straight, conical, tapering to an acute
point; upper mandible with the dorsal line straight, slightly convex at the
base, the ridge flattened toward the base, where it forms a short tapering
process on the forehead, the sides rounded, the edges inflected, the tip a
little depressed; lower mandible with the angle short and wide, the sides convex
at the base, toward the end rounded, the edges involute, the tip acute; the
gap-line ascending at the base, afterwards direct. Nostrils basal, oval, with a
small operculum. Head ovate, of moderate size; neck short; body moderately
stout. Feet of ordinary length, rather stout; tarsus compressed, with seven
anterior scutella; toes rather large, the first much stronger, the outer a
little shorter than the inner, and adherent at the base. Claws long, little
arched, compressed, laterally grooved, very acute. Plumage soft and blended,
glossy in the males. Wings of moderate length, with the outer four quills
nearly equal. Tail rather long, rounded. Roof of the upper mandible with three
longitudinal ridges; tongue tapering to a horny, flattened, slightly emarginate
tip; oesophagus wide, considerably dilated about the middle; stomach roundish,
muscular; intestine short and of moderate width; coeca very small, cloaca
oblong.