Birds of America
By John James Audubon, F. R. SS. L. & E.
GENUS I.--CERTHIA, Linn. TREE-CREEPER.
Bill about the same length as the head, very slender, arched, much
compressed, acute; upper mandible with the dorsal line arched, the ridge narrow,
the sides sloping at the base, nearly erect in the rest of their extent, the
edges sharp, arched, without notch, the tip acute; lower mandible with the angle
rather long, narrow, and pointed, the outline decurved, the sides erect and
convex, the edges inclinate, the tip acute. Nostrils linear-oblong, operculate.
Head ovate; neck short; body slender. Feet rather short, very slender, tarsus
rather shorter than the middle toe, very slender, much compressed; toes
extremely compressed; the first comparatively large, longer than the middle toe,
including the claw; the inner toe shorter than the outer; claws long, moderately
arched, slender, extremely compressed, laterally grooved, acute, that of the
hind toe very long. Plumage long, loose, very soft. Bristles obsolete. Wings
of moderate length, very broad; the first quill very short, the fourth and fifth
longest. Tail long, graduated, of twelve moderately stiff pointed feathers.