GKOUSE 139 



Females. The Black, tlie Red, the Spotted, the Yellow, 

 and the White. 



Added to the above are of course all the forms in 

 which mixtures of plumage of two or more of the types 

 appear. 



Although some of these forms are as widely different 

 from each other as they well can be, yet during the 

 breeding-season (May and June) there seems to be a 

 tendency towards a common j)lumage in all parts of tlie 

 British Islands — -the prevailing colour in the cocks being- 

 red, and in the hens Ijlack bars on a yellow ground ; in 

 nearly every case the white breast-feathers disappear. 



A few remarks on the forms of plumage in the males, 

 with regard to their occurrence and general distribution, 

 may not be out of place. 



The White Form. — To find Ijirds in this plumage two 

 essentials are necessary : one Ijeing high latitude towards 

 the Arctic Circle, and the other, height of elevation. 

 When these two conditions unite, the white form is, 

 generally speaking, the result ; but it is far from being 

 the case that either one or otlier of these is sutHcient to 

 cause this, and that Ijirds killed in higher latitudes or high 

 mountains are naturally lighter on the breast than others. 

 Orkney birds are not whiter than AVelsh specimens, neither 

 are birds killed high up on the mountains of AVales neces- 

 sarily whiter than Caithness ones. But combine the two, as 

 happens in the mountains of Sutherland, and there, on the 

 highest ranges, you get the white type in perfection. The 

 distance between Westmoreland (where the best English 

 white forms occur) and Sutherland is not really sulficient 

 to show a very great difference in the plumage ; but I 



