16 THE GROUSE IN HEALTH AND IN DISEASE 



nesting season is a dry one Grouse have been known to nest in very unsuitable 

 places, such as the beds of burns and dried-up pools and water-courses often 

 with most disastrous results when the weather breaks. 



But, if there has been no rain, the drowning theory must be discarded, and 

 its place is taken by the drought theory ; in other words, the fine, 

 dry, warm, sunny weather which is credited with producing a healthy 

 stock in a good year is the cause of their wholesale destruction in a bad year. 



Nor do we know exactly what proportion of Grouse meet their fate from 

 Vermin. vermin ; that a certain number are killed by foxes, ravens, hoodie 

 crows, stoats, weasels, and even gulls, may be admitted ; but when we 

 come to apportion the blame we again find ourselves without sufficient evidence 

 to amount to proof. The subject of vermin is dealt with more fully in another 

 part of the Report. 1 



Occasionally it is found that old birds as well as young have disappeared, 

 and when this happens it is customary to ascribe the cause to " Grouse 



Disease. * 



Disease " amongst the adult birds, for it is well known that if a parent 

 bird dies from disease or any other cause there is little chance of her brood 

 surviving. 



At a very early stage of the Inquiry it became evident that the loss of young 

 stock on a large scale had never hitherto been properly accounted for, and 

 required further investigation by the Committee. 



The Committee believe they can offer a solution of this problem. During 



their Inquiry into the causes of mortality in Grouse they discovered a certain 



unicellular intestinal parasite, one of the Protozoa, a Coccidium, known as 



Eimeria avium, which in certain cases is most destructive to the young 



chick, but is rarely fatal to the adult bird ; this Coccidium is fully 



described in another chapter of this Report. 2 The discovery of the disease 



caused by this pathogenic organism and known as Coccidiosis justifies the 



view that when there has been extensive mortality amongst the young stock 



which cannot be accounted for in any other way, it is almost certain that 



the chicks have met their fate by this infantile complaint. 3 



Coccidiosis as a disease of game birds and poultry is now being rapidly 

 recognised in this country, and the disease is* also being investigated in America. 



Still there remains the difficulty that the dead bodies are not found in 



1 Vide chap. xx. pp. 443 et seq. z Vide chap. xi. pp. 235 et seq. 



* Vide also vol. ii. Appendix G. 



