86 JOTTINGS ABOUT BIRDS. 



possessing it, or that it could have been acquired 

 by any selective process. It would, however, be 

 wrong to deny that many species derive inestimable 

 benefit from the colour of their plumage, either 

 by protecting them from enemies, or by rendering 

 them less likely to be seen by their victims whilst 

 in pursuit of their prey. We know how effective 

 the brown plumage of the desert bird is in con- 

 cealing that species amongst the sand and stones, 

 or how wonderfully protective is the white dress of 

 the Ptarmigan amidst the snow on the mountain 

 tops; but I maintain that we cannot reconcile this 

 particular change of colour, in its initial stages, with 

 any selective process, and must attribute it to the 

 fact of those birds dwelling in a climate which has 

 so modified their dress. As soon as the influence 

 of climate began to effect a change of colour in 

 any very specialized manner, and as soon as the 

 colour of the plumage became pronounced enough 

 to be very conspicuous, we can understand how 

 Natural Selection might then exert influence by 

 eliminating all individuals that did not in some 

 special way avail themselves of some method of 

 concealment. Species are gifted with an astonish- 

 ing amount of power for adapting themselves to 

 surrounding circumstances and to changing con- 



