154 ) 



XVL 



THE MOULTING OF BIRDS. 



PERHAPS there is nothing in the economy of birds 

 which is less understood than the seasonal changes in 

 their plumage. Moulting is a proceeding which bears 

 very closely indeed on some of the grandest questions 

 affecting organic life, especially as relating to sexual 

 selection, and the development of so much that is fair 

 and beautiful in the dermal covering of birds. One of 

 the first steps towards becoming a practical ornith- 

 ologist, is to master the seasonal changes which take 

 place in the feathers of birds, sexual differences of 

 plumage, and the dress which characterises the nestling 

 and immature stages of their existence. There can be 

 little doubt that many rare birds are overlooked in this 

 country every autumn, owing to the ignorance of 

 observers of the immature or winter plumage of such 

 species. It is rarely that adult birds stray so far from 

 their usual habitat ; it is the young and inexperienced 

 that lose their way, and drift to this country in autumn 

 with our streams of regular migrants. In many cases 



