ccc. Bill more or less truly conic, usually short, thick; commissure usually more or less evidently abruptly angulated near the base, or with lobe or tooth further forward. Nostrils obviously nearer culmen than tomia. Tarsus longer than lateral toe and claw.[13]
Bill stout, tumid, convex in nearly all its outlines; tomia not angulated, but with one or more lobes or nicks in advance of the base. Nostrils placed very high. Other characters much as in Sylvicolidæ. Colors chiefly red and yellow. One genus of … Tanagridæ.
Bill truly conic, much shorter than head, usually with the angulation evident; no lobe along middle of tomia, but usually a notch at end. Nostrils placed very high. Rictal bristles usually obvious … Fringillidæ.
Bill conic, but lengthened, little if any shorter than head; the angulation of the tomia evident; no notch at end. Nostrils high. No rictal bristles … Icteridæ.
bb. Primaries ten.
Otherwise with characters much as in Icteridæ … Sturnidæ.
d. Nostrils concealed with antrorse bristly feathers (except in Psilorhinus and Gymnokitta).[ ]
Base of bill sheathed with antrorse bristly feathers, having lateral branches to their very ends; its tip mostly notched. Basal joint of middle toe united only half-way to the lateral. Sides of tarsus occupied by a lateral groove, mostly filled in with small plates. First primary more than half as long as second. Large,—over seven inches … Corvidæ.
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.