COUVIDJE. 19 



Choughs. All species are resident within the limits of this work 

 except the Rook and the Hooded Crow, which are winter visitors 

 to the North and North- West. Their summer quarters are, how- 

 ever, not far off and their migrations are only partial and local 

 The members of the genera Corvus, or the true Crows, Pica, 

 the Magpies, Nucifraya, the Nutcrackers, and Pyrrhocorax, the 

 Choughs, are birds of wide distribution but the members of the 

 other genera are nearly all restricted to small areas. 



The Corvidce vary a good deal inter se in structure and habit. 

 In one or two genera the nostrils are not so completely hidden 

 by bristles as in the typical Crow. The majority feed completely 

 on the ground, others are strictly arboreal. They all agree in 

 laying four or five spotted eggs except certain species of the 

 genus Podoces, which lay white eggs in burrows. The mode of 

 nidification of the remaining genera varies greatly, some 

 species breeding in holes of trees and cliffs, the others, the 

 majority, constructing large nests of sticks and twigs. Most of 

 them are omnivorous, but some of the smaller tropical species 

 appear to confine their diet to insects. 



The Corvidce, as a family, have few characters in commoD, and 

 yet there is no group of birds which is more easily recognized. 



Key to Genera. 



A. Nostrils distant from forehead about one- 



third length of bill; narial bristles rigid and 

 straight, reaching to about middle of bill ;' 

 or rictal bristles and feathers of face absent. 



a. Tail much shorter than wing CORVUS, T>. 20. 



b. Tail much longer than wing PICA, p. 37. 



B. Nostrils distant from forehead less than oue- 



quarter length of bill; narial bristles or 

 plumes short, never reaching to middle of 

 bill. 



c. Tail greatly graduated, outer feathers less 



than half" length of tail. 

 a'. Middle tail-feathers uniformly wide 

 throughout or widening gradually to- 

 wards tip. 

 a". Bill red or yellow. 



a'". Tail more than twice length of 



wing UROCISSA, p. 40. 



b'". Tail less than twice length of 



winsr CISSA, p. 45. 



b". Bill black DENDROCITTA, p. 47. 



b'. Middle tail-feathers suddenlv broadening 



towards tip CRYPSIRHINA, p. 56. 



d. Tail not much graduated, outer feathers 



more than half length of tail. 

 c'. Graduation of closed tail less than length 

 of tarsus ; rictal bristles extremely 



long PLATYSMURUS. p. 58. 



c2 



