Cyanura. Head with lengthened narrow crest. Wing and tail blue, banded with black.
Cyanocitta. Head without crest. Above blue, with a gray patch on the back. No bands on wing and tail.
Xanthoura. Head without crest. Color above greenish; the head blue; lateral tail-feathers yellow.
Perisoreus. Head full and bushy. Bill scarcely half the head, with white feathers over the nostrils. Plumage dull.
B. Nostrils very large, naked, uncovered by feathers.
Psilorhinus. Head not crested; tail broad; wings two thirds as long as the tail.
Calocitta. Head with a recurved crest; wings less than half as long as the tail.
There is a very close relationship between the Jays and the Titmice, the chief difference being in size rather than in any other distinguishing feature. The feathers at the base of the bill, however, in the Jays, are bristly throughout, with lateral branches reaching to the very tip. In Paridæ these feathers are inclined to be broader, with the shaft projecting considerably beyond the basal portion, or the lateral branches are confined to the basal portion, and extended forwards. There is no naked line of separation between the scutellæ on the outer side of the tarsi. The basal joint of the middle toe is united almost or quite to the end to the lateral, instead of half-way. The first primary is usually less than half the second, instead of rather more; the fourth and fifth primaries nearly equal and longest, instead of the fifth being longer than the fourth.
Genus PICA, Cuvier.
Coracias, Linnæus, Syst. Nat. 1735 (Gray).