GKOUSE 137 



Grouse-ground or otherwise, and the disease once started, 

 it spreads so rapidly that the estate may be decimated in a 

 week, and it may extend its ravages over the whole country. 

 If the reader will look carefully into statistics of the 

 shooting-seasons during the past thirty years, he will find 

 that in nearly every instance the disease has broken out in 

 the year following an exceptionally good season. Appar- 

 ently too many birds have been left for breeding purposes ; 

 and when these have exhausted the supply of good 

 nourishing food, in the form of young heather, they are 

 forced to live on the old and rank herbage, etc., which has 

 the effect of generating the disease and causing the tape- 

 worms to grow. 



No bird has such extraordinary variability of plumage 

 as the Grouse, and it would not be at all difficult to write 

 an entire volume on its various changes and forms of 

 dress ; but as space forbids I have done my best to con- 

 dense these as much as possible to render them com- 

 prehensive to the reader in a small space, and I think that 

 the figures given may be of some interest, though I have 

 found it impossible to give illustrations of all the changes 

 in feather-casting, which are in reality coincidental in their 

 number with the Ptarmigan. Like that species, Grouse 

 are practically in a state of change throughout the entire 

 year, whether they are actually moulting or merely 

 altering the coloration of the feathers. The red and brown 

 shades which are prevalent colours of the Grouse's plumage 

 are not so striking as the corresponding ones of the 

 Ptarmigan. Therefore these numerous alterations are 

 consequently not nearly so noticeable ; and the interest 

 which naturalists take in the Grouse's plumage is not 



