ROOK 



591 



large numbers of grey crows make their appearance in autumn on 

 the east coast of England (where the black crow is of rare occurrence), 

 whence they distribute themselves over the country for the winter. 

 On the other hand, grey crows commonly breed in certain districts 

 of England and Wales, as well as in Ireland and Scotland ; and it is 

 noteworthy that the present species nests much more frequently on cliffs 

 than is the case with its sable brother. Both black and grey crows 

 (as well as rooks) feed largely on freshwater mussels, whose shells 

 they break by carrying them to a height and letting them fall on 

 rocks or stones ; and when it arrives on the east coast of England 

 the present species subsists to a great extent on cockles, which are 

 treated in the same unceremonious manner. 



Rook (Corvus Although frequently in England included under the 



fpus'ileg'us) generic title " crow," the rook is a very distinct 



species, characterised when adult by the presence 



of a bare, rough, grey area round the root of the beak due to the 



shedding of the short feathers with which this region is clothed, in 



MOUNTED IN THE ROWLAND 



immature birds. Owing to this peculiarity the rook is by some 

 ornithologists made the type of a genus by itself, under the name of 

 Trypanocorax frugilegus. Occasionalh- the feathers at the root of 

 the beak, as well as the bristly feathers over-arching the nostrils, are 

 retained in the adult, but in such cases the birds may be distinguished 



