THE CHANGES OF PLUMAGE IN RED GROUSE 69 



PART III. LOCAL VARIATION IN THE PLUMAGE OF THE GROUSE. 



The following notes are the outcome of an attempt to find 

 some broad differences between Grouse from the Highlands, 

 the Lowlands, the east coast and the west coast of Scotland, 

 and from English, Welsh, and Irish moors. 



It seemed possible that, with a large series of skins of a 

 species peculiar to the British Isles, and at the same time so 

 variable, one might discover points in the coloration of the 

 plumage or in the size of the birds which could be attributed 

 to the varying physical conditions under which they live. 



The artificial transportation of Grouse from one country 

 to another, generally from the southern moors to the northern, 

 often far removed from one another, with different food and 

 climate, has no doubt to some extent confused the issue. But 

 this is a difficulty which will increase rather than decrease, 

 and it is also possible that the purity of the British breed (at 

 present the only species of bird peculiar to our islands), may 

 before long be impaired by the introduction of a foreign species, 

 the Willow Grouse, on the mistaken supposition that the latter 

 is freer from the parasite of " Grouse Disease." This foreign 

 species has already been introduced here and there, and has 

 to some extent interbred with our own Red Grouse. 



The Committee's collection contains five hundred and eighty 

 skins of the Red Grouse, including five hundred and forty adult 

 birds of both sexes and forty chicks and pullets. These, however, 

 cannot be taken all together in one series. It is essential, for 

 purposes of comparison, that the male birds in their two plumages 

 should be taken separately in two lots, and the females in a similar 

 manner. Therefore the skins have to be divided as follows : 



No. of skins. 



Male birds in winter plumage . . . 241 



Male birds in autumn plumage . ;. ; 120 



Female birds in autumn plumage . . 108 



Female birds in summer plumage . 71 



Immature birds of the first six months 40 



