94 Order I 



therefore a public nuisance and not beneficial, as Rooks 

 are. From autumn to spring numbers are seen in the 

 open country or on the shore, but in spring our native 

 stocks retire to the woodlands or the hill-country, 

 where they build on a tree or rock a large nest of 

 sticks, lined with wool and other soft materials. The 

 four or five eggs resemble those of the Raven, but are 

 smaller. On the sea-coast the nest is often in a cliff. 

 Colonies are not formed. The flight is similar to that 

 of the next species. 



The Rook (C. frugilegus), on the other hand, breeds 

 in colonies often of hundreds of birds, the larger 

 rookeries being also used as winter resorts. The nests 

 are usually on lofty trees, but in quiet places may be 

 much nearer the ground and exceptionally on it ; they 

 are built of sticks and mainly lined with straw, while 

 the eggs are " small editions" of those of their congeners. 

 In the rookeries a vast amount of cawing is always 

 going on, and the birds are tame enough, but at other 

 times they are very wary, and constantly post sentinels 

 when feeding in the fields. The amount of insect pests 

 that is consumed must be incalculable, and the Rook 

 is doubtless of the greatest utility, but in certain places 

 it takes to bad habits and imitates the Crow in the 

 destruction of eggs of game. This simply points to 

 the fact that the natural food-supply will only maintain 

 a certain number of individuals, and that any excess 

 should be checked by shooting the young. This species 

 is found breeding throughout Britain as far north as 

 the Orkneys ; it does not do so in southern Europe, 

 but ranges over the northern portion and to Siberia. 

 An adult Rook is characterized by a broad tract of 

 white warty skin round the base of the bill, but the 



