Family XXIII. SITTINAE. NUTHATCHES.
Bill of moderate length or rather long, straight, rather slender, conico-subulate, somewhat compressed, with the tips acute, or cuneate. Head ovate; neck short; body full. Tarsi rather short, or of moderate length, slender, compressed, with seven or eight scutella; toes long, very slender; hind toe extremely long; anterior little spreading; claws long, little arched, slender, much compressed, acute. Plumage soft and full. Wings of moderate length, broad, rounded. Tail short, broad, of twelve feathers. Roof of upper mandible very narrow, slightly concave, with three ridges; tongue very slender, with the tip abrupt and bristly; oesophagus without dilatation; stomach roundish, moderately muscular; intestine short and wide; coeca very small. Trachea simple; with a single pair of large inferior laryngeal muscles. Allied to the Titmice on the one hand, and the Woodpeckers on the other.