130 ANNALS OF SCOTTISH NATURAL HISTORY 



published the above interesting volume that the moults of 

 the Ptarmigan and Red Grouse were coincidental in number ; 

 but I have since conclusively proved that this is not really 

 the case, the changes in the male and female Red Grouse 

 occurring at different seasons, and being in this respect quite 

 peculiar. See " Annals and Magazine of Natural History " 

 (6), xii. pp. 62-65 (1893), and " Catalogue of the Birds in the 

 British Museum," xxii. pp. 36-38 (1893). 



The Willow Grouse (Lagopus lagopus} of which the 

 Red Grouse is considered by most ornithologists merely an 

 insular form has three distinct partial moults during the 

 year. Seeing that the latter species does not assume the 

 white winter garb, one is very naturally led to suppose that 

 this protective plumage, being no longer a necessity, has 

 been gradually dropped, and that the spring and autumn 

 plumages only are retained ; but this is only the case with 

 the female. 



For many years the changes in the plumage of the Red 

 Grouse has been one of my special studies, but it was only 

 during the preparation of the above-mentioned volume of the 



Catalogue that I was able to bring together a fairly complete 

 series of birds of both sexes shot during every month of the 



year, and thus obtain absolute confirmation of what I had 



long suspected. 



The male has no distinct summer plumage, but has 



distinct autumn and winter plumages, and retains the latter 



throughout the breeding season. 



The female has a distinct summer plumage, which is 



complete by the end of April or beginning of May ; also a 



distinct autumn plumage, which is retained till the following 



spring. 



To put it more shortly, both male and female have two 



distinct moults during the year, but in the male they occur 



in autumn and winter, and in the female in spring and 



autumn ; the former having no distinct spring, and the latter 



no distinct winter, plumage. 



So far as I am aware, these remarkable facts are without 



parallel in ornithology. 



Since I last wrote on this subject in vol. xxii. of the 



" Catalogue of Birds," I have examined much additional 



