482 THE GROUSE IN HEALTH AND IN DISEASE 



condition. There is no possible doubt that their power of flight has much 

 increased in the last twenty years. 



The system of driving over one set of butts is suitable, of course, to a very 

 limited number of moors, and even when possible might not be adopted for 

 reasons unnecessary to mention here. The system is mentioned solely as a 

 possible explanation of the remarkable change that came over this moor at a 

 time which coincided with its adoption. 



