282 Birds of Colorado 



Family CORVIDiE. 



Generally large birds with the nostrils concealed by 

 bristles (except Cyanocephalus) ; bill variable in shape, 

 but usually as long as the head, compressed and conical 

 and never distinctly notched ; wing of ten primaries, 

 the outer (tenth) well developed, and about half the length 

 of the ninth ; tail of twelve rectrices ; tarsus small, scutel- 

 lated in front, the hinder aspect covered with two long 

 laminae forming a sharp posterior edge ; sexes alike ; 

 young closely resemble the adults ; an autumn moult only. 



Key of the Genera. 



A. Tail much longer than the wmgs ; no crest. Pica, p. 282. 



B. Tail about the same length as the wing. 



a. Head crested ; plumage chiefly blue. Cyanocitta, p. 28-4. 



b. No crest. 



a^ Bill about as long as the head ; plumage chiefly blue. 



Aphelocoma, p. 287. 

 b^ Bill about half as long as the head ; plumage grey. 



Perisoreus, p. 289. 



C. Tail very markedly shorter than the wing. 



a. Nostrils concealed by long plumes covering the basal third 



of the bill ; plumage black. Corvus, p. 291. 



b. Nostrils concealed by short plumes, less than I the length of 



the bill ; plumage grey, black and white. Nucifraga, p. 295. 



c. Nostrils exposed ; plumage blue. Cyanocephalus, p. 297. 



Genus PICA. 



Bill short and strong, its basal half as well as the nostrils concealed 

 by the nasal plimies ; no crest ; wing short and rounded, the outer 

 (tenth) primary short, falcate and about half the length of the ninth ; 

 tail very long, markedly exceeding the wing in length, very strongly 

 graduated, the outer feathers about half the length of the central pair. 



This genus is distributed over the whole of the Palsearctic region, 

 and the western half of North America. 



One species, separable from the common Magpie of the Old World 

 only by a subspecific characters, is found in Colorado. 



American Magpie. Pica pica hudsonia. 

 A.O.U. Checklist no 475 — Colorado Records — Pike 10 vol. ii., p. 460 

 (Coues' ed.) ; Say 23, vol. ii., p. 182 ; Baird 58, p. 576 ; Allen 72, pp. 150 



