3 1 o Poa ch e rs a n d Poach ing. 



process of natural selection. As an instance of 

 the first, we have the change from dark brown to 

 purely white of the stoat or ermine ; of the 

 second, the indigenous red grouse of the British 

 Isles is an example. This bird is found nowhere 

 else in a wild state. With us there is no reason 

 why it should assume the white winter plumage 

 like its congeners, and yet there can be no 

 question that our bird is the local representative 

 of the white willow-grouse, which ranges over 

 the whole of Northern Europe. There are 

 absolutely no structural differences between the 

 two. Here is a species, then, which has lost, 

 through disuse, the power of turning white in 

 winter with the absence of the necessity for 

 doing so. 



Let us see how the adoption of protective 

 colouring holds as applied to these species all of 

 which are brown in summer, white in winter. 

 The Iceland falcon and the ptarmigan have 

 pretty much the same habitat, the one preying 

 upon the other. The ptarmigan's plumage during 

 the breeding season is dark brown, even approach- 

 ing to black ; but in autumn, during the transition 

 stage, it is grey, this being the general tint of the 

 mosses and lichens among which it lives. Sup- 

 pose, however, that the summer bird never 

 changed its plumage, what chance of survival 

 would it stand against its enemies when the 

 ground was covered with snow ? Remaining, as 



