240 BBITISH BIRD3 



rump, upper tail-coverts, and the four middle curled tail-feathers 

 black ; the rest of the tail-feathers grey ; flanks and beUy greyish 

 white ; under tail-coverts velvet-black ; legs and feet orange-red. 

 Length, two feet. Female : smaller ; bill greenish ; crown dark 

 brown; general plunjage mottled brown and buff; speculimi 

 green. 



The mallard is the most common and best-known freshwater 

 duck in Britain, and is a resident species, breeding in suitable 

 localities throughout the country ; but the birds that breed and 

 remain all the year are few in number compared to the migrants 

 that come to us in winter from more northern regions. In the 

 domestic state the mallard is, next to the fowl, the most abundant 

 and familiar bird we possess. The tame duck differs from the mal- 

 lard only in its heavier body and shorter wings, and in being poly- 

 gamous instead of monogamous in its habits. The tendency to vary 

 in colour is a result of domestication in all species. Tt was from 

 observing the annual change in the plumage of the domestic drake 

 that the discovery was made that ducks differ from other birds in 

 the manner of their moult. The period of the moult does not coin- 

 cide in the drake and duck ; and this discrepancy in the sexes has 

 caused ducks to differ in their breeding habits from all other birds. 

 Thus, in most birds, male and female share the labours of incuba- 

 tion, and of rearing and protecting the young ; and the moult, which 

 is always a period of danger, during which the bird is obliged 

 to go into hiding, takes place some time after the young are able 

 to shift for themselves — in other words, the family tie is broken 

 after it has ceased to be necessary ; and the female of the mallard, 

 and of other ducks, moult in this way. Not so the male. He is 

 smitten by the change after the eggs are all laid and incubation begun ; 

 with the result that the marriage tie is dissolved just at the period 

 when his help is most needed. This is one of the strangest things 

 in bird history ; for up to the time when the physical change begins 

 the drake is not less loving and solicitous than any other male bird, 

 and if by chance the moulting period is delayed, he continues to 

 guard the nest and share the labours of incubation ; so that we may 

 say, without straining a metaphor, that the drake is forcibly torn 

 away from his marital duties, just as the late-breeding swift or 

 swallow is sometimes forced by an overpowering migratory instinct 

 to abandon its helpless young in the nest. The action of the swift 

 in leaving its helpless yoimg to perish of starvation in the nest is 



