110 CONTROLLED NATURAL SELECTION 



female, except perhaps the habit the male 

 has of always rising first, when the pair is 

 flushed. In this bird, pre-copulatory displays 

 are by no means wanting. There yet remain 

 to be accounted for, the Greylag Goose, Sand- 

 martin, Tree Sparrow, and Tree-creeper; some- 

 thing might be said of each, but controversial 

 and therefore doubtful facts would have to 

 be utilised. 



DIVISION II 



This division includes birds presenting 

 bi- sexual attracting coloration for the pro- 

 tection of their cryptically, or much less 

 brilliantly coloured young. 



Many of these birds have a seasonal moult : 

 in the winter, when they do not possess young, 

 they don a cryptic dress. In some the change 

 from juvenile to adult plumage is slow, and 

 extends over several years : usually these 

 full-grown but not maturely coloured birds 

 do not breed, and therefore do not require 

 attracting coloration for protection of young. 

 Further, adult and immature birds often keep 

 together, in companies, for several seasons, 

 in which case the gradual change from juvenile 

 to adult plumage would be a prolonged ad- 



