ORIGIN AND CHARACTERISTICS 25 



cases modifications of colour for purposes of 

 concealment, whilst yet another branch of this 

 fascinating subject of animal colouration deals 

 with the curious phenomena of Mimicry (in 

 birds the known instances are comparatively 

 few) and with recognitory and warning colours. 

 (Conf. Curiosities of Bird- Life ^ Chaps, vii. viii.) 



We cannot well leave the interesting subject 

 of plumage without devoting a few lines to the 

 moulting of birds. Moulting is the changing 

 or renewal at stated periods of the old abraded 

 and worn feathers, these being shed and re- 

 placed by new ones. Every living bird is sub- 

 ject to this process at least once every year, a 

 complete change of dress usually taking place 

 shortly after the breeding season is over. In 

 addition there are many birds that undergo a 

 complete moult twice in the year, in spring 

 and autumn ; others which have a partial 

 moult in spring as well as the full moult in 

 autumn ; whilst others, yet again, may almost be 

 said to be in a chronic state of moult throughout 

 the year. Birds with a double or partial spring 

 moult undergo this just previous to the nuptial 

 season, then acquiring those various wed- 

 ding ornaments for which so many species are 

 famous. So far as concerns the smaller contour 



