242 THE GROUSE IN HEALTH AND IN DISEASE 



Hymcnolepis (tapeworms), or Trichosoma (threadworms), or 

 both ; the main gut by a far more bulky mass of Davainea 

 (tapeworms) ; and the caeca may be reddened from end to end by 

 villous engorgement due to the irritating presence of thousands 

 of Trichostrongylus (threadworms). In this state the bird is 

 flushed and shot, and forwarded for a diagnosis. 



And still one more perplexing item, namely, that scattered 

 here and there amidst thousands of Trichostrongylus ova, in 

 the contents of the intestine, are encysted spores of coccidia, 

 showing that the bird may have lost weight in the height of 

 the summer by excessive Coccidiosis, and yet have survived. 



That these birds are recovering, and not dying, is proved 

 by the fact that no fresh corpses are found, and gradually the 

 piners become fewer as the period of convalescence proceeds, 

 until in November and December there is not a sickly bird 

 to be found on any moor. It follows that the common practice 

 of ruthlessly killing down the stock in a disease year with a 

 view to stamping out the disease is bad policy, for if the birds 

 were allowed to live they would all recover their health before 

 the end of the year. 



Turning now to the hens we find from Chart (D') that April 

 and May are again the months of highest mortality. It is 

 true that the death roll is not so heavy as in the case of the 

 cocks, and this is quite in accordance with the experience of 

 gamekeepers and naturalists by whom it is almost invariably 

 observed that, in the spring, cock Grouse die from disease in a 

 much larger proportion than hens. On the other hand, it is 

 frequently noted that hens continue to die after the cocks 

 have recovered their health, and this is confirmed by the Chart, 

 Avhich shows that the recovery of the hens is slower. The 

 fact is still more clearly shown in Chart (E'), which shows that 

 in August a very considerable proportion of hens are still suffer- 

 ing severely from the after effects of the spring outbreak, 



The difference in the liability to sickness of the cock and 

 lien respectively is almost certainly due to the difference in 

 the conditions affecting each sex. 



