CHAPTER II 



THE CHANGES OF PLUMAGE IN THE RED GROUSE IN 

 HEALTH AND IN DISEASE 



THE subject of the plumage of the Grouse has already been 

 briefly referred to, and the chief object of the following chapter 

 is to describe in greater detail the somewhat complicated series 

 of changes which occurs each year in the normal Grouse, and 

 to show to what extent a departure from the usual rule may 

 serve as an indication of the health of individual birds or of 

 the stock as a whole, 



PART I. PLUMAGE CHANGES OF THE COCK GROUSE 



When a large number of skins of the cock Grouse are 

 arranged together, side by side, according to the month in which 

 the birds were killed, it will be found that, even taking into 

 account the differences of well-marked local variations in 

 plumage, the series can readily be divided into two very dis- 

 tinct sets. 



There is first a very marked uniformity in the plumage of 

 the cock birds killed from the middle of November to the end 

 of June ; and likewise amongst those killed from the end of 

 June to the middle of November. 



These two periods, November to June and June to November, 

 mark the two seasonal changes of plumage in the cock Grouse. 



The first is a plumage worn throughout the winter and during 

 the courting and breeding season of the spring. 



The second is a plumage worn throughout the late summer 

 and early autumn. 



It is necessary to lay stress upon this general broad division 



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