Family ICTERIDÆ.—The Orioles.
Char. Primaries nine. Tarsi scutellate anteriorly; plated behind. Bill long, generally equal to the head or longer, straight or gently curved, conical, without any notch, the commissure bending downwards at an obtuse angle at the base. Gonys generally more than half the culmen, no bristles about the base of bill. Basal joint of the middle toe free on the inner side; united half-way on the outer. Tail rather long, rounded. Legs stout.
This family is strictly confined to the New World, and is closely related in many of its members to the Fringillidæ. Both have the angulated commissure and the nine primaries; the bill is, however, usually much longer; the rictus is completely without bristles, and the tip of the bill without notch.
The affinities of some of the genera are still closer to the family of Sturnidæ or Starlings, of which the Sturnus vulgaris may be taken as the type. The latter family, is, however, exclusively Old World, except for the occurrence of a species in Greenland, and readily distinguished by the constant presence of a rudimentary outer primary, making ten in all.
There are three subfamilies of the Icteridæ,—the Agelainæ, the Icterinæ, and the Quiscalinæ,[29] which may be diagnosed as follows, although it is difficult to define them with precision:—
Agelainæ. Bill shorter than, or about equal to, the head; thick, conical, both mandibles about equal in depth; the outlines all more or less straight, the bill not decurved at tip. Tail rather short, nearly even or slightly rounded. Legs longer than the head, adapted for walking; claws moderately curved.
Icterinæ. Bill rather slender, about as long as the head; either straight or decurved. Lower mandible less thick than the upper; the commissure not sinuated. Tarsi not longer than the head, nor than middle toe; legs adapted for perching. Claws much curved.
Quiscalinæ. Tail lengthened, considerably or excessively graduated. Bill as long as,or longer than, the head; the culmen curved towards the end, the tip bent down, the cutting edges inflexed, the commissure sinuated. Legs longer than the head, fitted for walking.