Family PICIDÆ.—The Woodpeckers.
Char. Outer toe turned backwards permanently, not versatile laterally, the basal portion of the tongue capable of great protrusion.
The preceding characters combined appear to express the essential characters of the Picidæ. In addition, it may be stated that the tongue itself is quite small, flat, and short, acute and horny, usually armed along the edges with recurved hooks. The horns of the hyoid apparatus are generally very long, and curve round the back of the skull, frequently to the base of the bill, playing in a sheath, when the tongue is thrown forward out of the mouth to transfix an insect.
There are twelve tail-feathers, of which the outer is, however, very small and rudimentary (lying concealed between the outer and adjacent feathers), so that only ten are usually counted. The tail is nearly even, or cuneate, never forked, the shafts very rigid in the true Woodpeckers; soft in Picumninæ and Yunginæ. The outer primary is generally very short, or spurious, but not wanting. The bill is chisel or wedge shaped, with sharp angles and ridges and straight culmen; sometimes the culmen is a little curved, in which case it is smoother, and without the ridges. The tarsi in the North American forms are covered with large plates anteriorly, posteriorly with small ones, usually more or less polygonal. The claws are compressed, much curved, very strong and acute.
The Picidæ are found all over the world with the exception of Madagascar, Australia, the Moluccas, and Polynesia. America is well provided with them, more than half of the described species belonging to the New World.
The subfamilies of the Picidæ may be most easily distinguished as follows, although other characters could readily be given:—
Picinæ. Tail-feathers pointed, and lanceolate at end; the shafts very rigid, thickened and elastic.
Picumninæ. Tail soft and short, about half the length of wing; the feathers without stiffened shafts, rather narrow, linear, and rounded at end.
Yunginæ. Tail soft and rather long, about three fourths the length of wing; the feathers broad, and obtusely rounded at end.
Of these subfamilies the Picinæ alone occur north of Mexico. The Yunginæ, to which the well-known Wryneck of England (Jynx torquilla) belongs, are exclusively Old World; the Picumninæ belong principally to the tropical regions of America, although a few species occur in Africa and India. One species, Picumnus micromegas, Sundevall, belongs to St. Domingo, although erroneously assigned to Brazil. This is the giant of the group, being about the size of the White-bellied Nuthatch (Sitta carolinensis) the other species being mostly very diminutive, varying from three to four inches in length.