Base of bill with two tufts of bristly feathers, ending in simple filaments without lateral branches, its tip mostly unnotched. Basal joint of middle toe united nearly all its length with the lateral. Sides of tarsus ungrooved. First primary less than half as long as second. Small,—under seven inches … Paridæ.15
dd. Nostrils exposed.
e. Tail scansorial, with rigid acute feathers. Whole bill slender, compressed, acute, decurved, unnotched, unbristled. Outer toe much longer than inner … Certhiidæ.
ee. Tail not scansorial, graduated. First primary not less (generally more) than half as long as the second, and inner toe united to the middle by at least one half (usually more) of the length of its basal joint.
Tarsus with few obscure scutella. Rictal bristles present. Bill stout, but not toothed nor hooked. Wing excessively rounded (fifth, sixth, and seventh primaries longest), much shorter than the long graduated tail. Size small. Plumage brown, unbanded … Chamæadæ.
Tarsus distinctly scutellate. Nostrils wholly exposed, scaled. No rictal bristles, but loral feathers with bristly points. Bill slender, not notched nor hooked. Wings and tail moderately rounded; neither very much shorter than the other. Size small. Color brown, etc., the wings and tail barred or undulated … Troglodytidæ.
Tarsus distinctly scutellate. Nostrils overhung (not concealed) with bristly feathers. Rictal bristles present, strong. Bill powerful, compressed, strongly notched, toothed, and hooked. Wings and tail moderate. Large. Colors black, white, and gray … Laniidæ.
eee. Tail not scansorial. First primary less than half as long as the second,16 or about half as long, in which case the inner toe is cleft nearly to its base (f and ff).
f. Basal joint of middle toe united some distance with the inner, and for half or more of its length with the outer toe.
Basal joint of middle toe shorter than that of inner toe, and wholly adherent to both inner and outer toes. Tarsus longer than middle toe and claw. Gonys more than half the length of the lower jaw. Bill stout, high, compressed; notched and abruptly hooked at tip … Vireonidæ.
Basal joint of middle toe not shorter than that of inner toe; united to the outer for about two thirds, to the inner for about one half, its length. Tarsus not longer than the middle toe and claw. Gonys less than half the length of the under jaw. Bill triangular, much depressed at base, moderately notched, and hooked at tip17 … Ampelidæ.
Basal joint of middle toe shorter than that of the inner toe, united to the outer for about two thirds, to the inner for about one half, its length. Tarsus longer than middle toe and claw. Gonys more than half the length of the under jaw. Bill very weak and slender, little decurved or notched at tip. Very small,—under six inches long. (Tarsi booted in Regulus, distinctly scutellate in Polioptila.) … Sylviidæ.
ff. Basal joint of middle toe quite free from the inner, and not united with the outer more than half-way.
Nostrils linear, low. No bristles or bristly points whatever about the mouth. Wings short, rounded, concavo-convex. Tail very short, nearly concealed by its coverts. Tarsi booted … Cinclidæ.
Nostrils oval. Bristles or bristly points about the mouth. Wings very long and pointed, reaching, when folded, beyond the middle of the short, square, or emarginate tail, and one and a half times or more the length of the latter; tip formed by second, third, and fourth quills; outer secondary reaching only about two thirds way to end of longest primary; spurious quill very short. Tarsi booted … Saxicolidæ.
Nostrils oval. Bristles or bristly points about the mouth. Wings moderate, not reaching, when folded, beyond the middle of the tail, and not over one and a third times as long as the latter; tip formed by third to sixth quill; outer secondary reaching in closed wing three fourths or more the length of the longest primary. Spurious quill longer, sometimes one half the second. Tarsi scutellate in Miminæ, booted in Turdinæ … Turdidæ.
aa. Outside of tarsus covered with two series of scutella,—one lapping entirely around in front, the other entirely around behind, and meeting at a groove on the inside; hind edge blunt. First primary spurious or apparently wanting. Hind claw much lengthened, scarcely curved. Nostrils with antrorse bristly feathers. Bill conico-elongate … Alaudidæ.
B. Clamatores. Outside of tarsus covered with a series of plates variously arranged, lapping entirely around in front and behind, to meet at a groove on the inner side.
First primary lengthened, often longest, at least over two thirds as long as the longest. Bill broad at the base, much depressed, tapering to a fine point, which is abruptly decurved; culmen rounded or flattened; gonys flattened; commissure straight, or nearly so, to the tip. Nostrils small, circular, basal; overhung, but not concealed by bristles. Mouth capacious, with broad and deeply fissured rictus, beset with numerous long strong bristles. Feet small, weak. Tail of twelve feathers … Tyrannidæ.
Secondaries only six.
Bill tenuirostral, longer than head, nearly cylindrical. Gape constricted. Tongue filiform, extensile, bi-tubular. Wings long in terminal portion, abbreviated proximally, acute. Plumage compact, of metallic sheen. Size smallest of all birds. (Humming-Birds.) … Trochilidæ.
Secondaries more than six.
Feet syndactyle by connation of outer and middle toes.
Outer toe much longer than the inner, united for half its length with the middle, forming a broad sole. Tibiæ naked below. Bill longer than head, straight, acute, with hard cutting edges and ample rictus. Tongue rudimentary, fixed. Wings pointed, much longer than the short square tail. Tail-feathers twelve. Plumage compact, oily. (Kingfishers.) … Alcedinidæ.
Feet zygodactyle18 by reversion of outer or fourth toe.
Not scansorial; tail of eight or ten long soft feathers. Bill with decurved tip, not fitted for hammering; rictus ample. Tongue not extensile nor vermiform nor barbed. Salivary glands and hyoidean apparatus not peculiar. No nasal tufts of feathers. Arboreal and terrestrial. (Cuckoos.) … Cuculidæ.
Highly scansorial; tail of twelve rigid acuminate feathers, whereof the outer pair are short and spurious, concealed between bases of next two pairs. Bill stout, straight, with the tip truncate or acute, not decurved,—an efficient chisel for hammering and boring wood. Tongue vermiform, extensile,19 and barbed. Salivary glands large; hyoidean apparatus peculiar. Nasal tufts usually present. Arboreal. (Woodpeckers.) … Picidæ.
Feet neither syndactyle nor zygodactyle.
Feet semipalmate, of normal ratio of phalanges. Anterior toes connected at base by movable webbing. Hind toe very small, elevated, semilateral. Middle toe produced, its large claw pectinate. Bill fissirostral, with very small, triangular, depressed horny part and immense rictus, reaching below the eyes, furnished with bristles. Rather large. Plumage soft and lax, much variegated … Caprimulgidæ.
Feet scarcely or not semipalmate, of frequently abnormal ratio of phalanges (middle or outer toe, or both, with fewer joints than usual among birds). Hallux very small, elevated, frequently lateral or versatile. Middle toe not produced nor its claw pectinate. Bill much as in the last, but rictus unbristled. Small. Plumage compact, of few simple subdued colors … Cypselidæ.
To characters of Psittaci add: Cere feathered, concealing the nostrils. Feet granular, rugose. Wings pointed. Tail cuneate. Plumage coarse and dry. Head feathered. Colors green, with yellow and blue … Psittacidæ.20
Feet