PHYSIOLOGY AND ANATOMY OF RED GROUSE 127 



Of these two cases, the first had been five days dead, and the other three, in 

 August and 2^ost-')nortem change had set in. The condition cannot be con- 

 sidered in any way directly connected with Strongylosis, or more than two 

 cases would have been found in a series of nearly two thousand examined. 



The testes appear often to run a normal course of development as the 

 breeding season approaches, however seriously the bird may be diseased. The 

 first sign of any increase in the size of the testes is to be found ^ 



o ■' , Testes. 



about the third week of February, at least in the northern half of 

 Scotland. Further south it might be found a little earlier perhaps, but in 

 1908 for Banffshire the date was February 23rd, while for Durham it was 

 February 24th. In May the testes have increased in size to twenty or thirty 

 times the bulk they had during inactivity, and they are then white and fatty, 

 whereas in winter they are generally small and black and deeply pigmented. 



Occasionally a very emaciated cock bird will be found with testes only 

 half the normal size during the breeding season ; but, as a rule, the effect 

 of disease on the development of the hen's generative system, both ovar}' 

 and oviduct, is far more noticeable than is the case in the male. 



If we allow that the prenuptial moult has become post-nuptial in the 

 male as a result of chronic parasitism, it is conceivable that the same saving 

 of energy allows of this sexual development in the male ; whereas in the 

 female, in which the moult is prenuptial as it should be, there are no " savings " 

 to fall back upon in the event of bad disease, and therefore the sexual develop- 

 ment is unsupported, and none takes place. 



It is very noticeable that in sick Grouse hens there is no development of 

 the ovaries or enlargement of the oviduct and cloaca, such as takes 



. . Ovaries. 



place in spring in every healthy hen. The ovaries remain small and 

 undeveloped as in midwinter. Such birds are barren if they pair, for as a 

 rule they cannot lay an egg, but they pair nevertheless, as every gamekeeper 

 knows to his cost in a bad year. 



Such birds are often very backward in their plumage change as well, 

 suggesting that the time may come when the hens as well as the piumage 

 cocks may have to don the prenuptial dress when the breeding season in^dtseased 

 is finished instead of before it, as is the custom with the hen ^"■'^^• 

 Grouse now (see chapter iii. p. 45). 



For example, Nos. 1878 and 1879 were two hen Grouse found dead of 

 Strongylosis in May. One had put on the full breeding plumage, but was 



