148 BIRDS AND THEIR CHANGING HABITS 



that here, as elsewhere, the truth may lie 

 between the two extremes, and that the facts 

 of numbers, locality and opportunity must all 

 be considered. In undue numbers rooks, like 

 other birds and beasts, may well become a 

 plague, and all the more when there is no 

 natural enemy left but man to keep their 

 numbers in check. It is, however, no longer 

 the farmer alone who complains of the damage 

 done by rooks ; the sportsman and the game- 

 keeper have awakened to the fact that these 

 birds have, comparatively recently, developed a 

 new and vicious taste for the eggs and even the 

 young of our game and other birds. This is 

 particularly the case when a long period of 

 cold and arid easterly winds, coinciding with 

 the breeding season, has seriously diminished 

 the natural food supply just when the demands 

 of the young rooks are most clamant ; and the 

 bad habit, once established, unfortunately remains 

 even when the original predisposing cause no 

 longer exists. 



In the Report of the Committee appointed 

 by the Board of Agriculture to enquire into the 

 great plague of voles which occurred in 1888-90 

 there is an interesting note in the evidence of 

 a well-known naturalist, the late Mr. Robert 

 Service of Maxwelltown, who drew attention to 



