Erythaca (Sialia) Arctica, Arctic Blue Bird, Swains. & Rich. F. Bor. Amer. v. ii. p. 209.
Arctic Blue Bird, Sialia Arctica, Nutt. Man. v. ii. p. 573.
Arctic Blue Bird, Sylvia Arctica, Aud. Orn. Biog. v. v. p. 38.
FAMILY XII. TURDINÆ. THRUSHES.
Bill short, or of moderate length, rather strong, straight, compressed toward the end; upper mandible with its dorsal outline a little convex and declinate, the tip small, rather acute, the notches small; lower mandible with the angle rather short, of moderate width, the dorsal line straight, the sides convex, the tip acute. Head oblong, compressed, of moderate size; neck rather short; body moderate. Eyes of moderate size. External aperture of ear large and roundish. Feet of moderate strength; tarsus compressed, with seven anterior scutella; toes rather strong, compressed; first, second, and fourth, nearly equal, third much longer, and adherent to the fourth at the base; claws rather long, arched, compressed, laterally grooved, acute. Plumage rather blended. Bristles small. Wings of moderate length, broad, rounded; the first quill very small, third and fourth longest. Tail of twelve feathers, varying in length. Tongue sagittate, and papillate at the base, slender, tapering, its tip slit. Œsophagus rather narrow, without crop; proventriculus oblong; stomach a gizzard of moderate strength, its lateral and lower muscles distinct; the epithelium dense and rugous; intestine of moderate length; cœca very small, cylindrical. Trachea simple, with four pairs of inferior laryngeal muscles.
GENUS I. CINCLUS, Bechst. DIPPER.
Bill rather short, slender, slightly ascending, much compressed toward the end; upper mandible with its dorsal line straight until toward the end, the ridge rounded, the sides convex, the edges somewhat inflected, with an obscure notch close to the narrow deflected tip; lower mandible slightly bent upwards, the angle medial and very narrow, the dorsal line ascending and slightly convex, the tip narrow and rather acute. Nostrils linear, direct, exposed. General form short, full, and compact. Head oblong, compressed. Legs strong; tarsus of moderate length, compressed, covered anteriorly with a long undivided plate and four inferior scutella; toes rather large and strong; claws arched, much compressed, laterally grooved, that of the hind toe considerably larger. Plumage ordinary, rather blended. Bristles obsolete. Wings rather short, convex, rounded. Tail short, even.
137. 1. Cinclus Americanus, Swains. American Dipper.
Plate CCCLXX. Adult. Plate CCCCXXXV. Young.
Head and neck chocolate-brown, upper parts very deep bluish-grey, lower somewhat lighter, and tinged anteriorly with brown. Young with the upper parts deep bluish-grey, the head and hind neck slightly tinged with brown; lower parts lighter, the feathers margined with whitish, the throat with a slight tinge of brown.