2 LIFE-HISTORIES OF BIRDS 



but a few exceptions, among our types. By the above feature. 

 we can discriminate the Corvidtc from all our other species. 

 excepting the Paridcc; but even here the mutual resemblance 

 is so close that no obvious technical character of external form 

 can be pointed out as a distinction. Sixe is clearly distinc- 

 tive, for it is well known, all Corvldcr* without exception. 

 are much larger aves than the Pariihc. 



The number of species is quite difficult to settle, being 

 differently computed by various ornithologists. This is 

 owing to the uniformity of color which prevails in the 

 prominent family-groups, as well as to an apparent plasticity 

 of organization in many forms. Mr. G. R. Gray estimates 

 fifty genera and sub-genera, embracing two hundred species, 

 \vhich Dr. Cones deems too excessive, and thinks should 

 suffer a reduction of one-third in both cases. They have 

 been classed in five subfamilies, three of wdiich pertain to 

 the Old World, being represented most largely in the 

 Indian and Australian regions ; while the remaining two. 

 which embrace the great bulk of the family, may be con- 

 sidered more nearly cosmopolitan. These are the Cor-chnc 

 and GarrulincB) which, so far as our own forms are con- 

 cerned, are easily distinguishable. 



Subfamily CorvinaB. Crows. 



The wings are long and pointed, and much longer than 

 the tail. The tip is formed by the 3d, 4th, and 5th quills. 

 The legs are stout, well adapted both to walking and perch- 

 ing. The color, as a rule, is sombre or un variegated, blue 

 being exceedingly rare. The sexes are not dissimilar, and 

 the alterations of plumage, scarcely noticeable. These birds 

 are quite unmusical ; the voice of the larger species being- 

 raucous ; that of the smaller, strident. They have no choice 

 of localities, walk firmly and easilv on the ground, and are 

 the most nearly omnivorous of birds, which, combined with 

 their robust and hardy nature, render them seldom if ever 

 truly migratory. Their nidification varies according to sur- 

 roundings ; the fabric being ordinarily rude and cumbersome. 



