i8 A BOOK OF BIRDS 



become curiously indented with fine grooves known as '* hunger- 

 marks." 



The annual moult takes place generally after the breeding-season ; 

 but some birds moult again in spring, when a new and more resplendent 

 livery is put on, as in the case of many of the Plover tribe. But the 

 quills in such cases are not renewed. In some of the Ducks, as in the 

 drake of the common Wild Duck, a dull livery, resembling that of his 

 mate, is assumed — the so-called '' eclipse " dress — -during the month 

 of June, and this is worn for some weeks. By the middle of August 

 the new and characteristic " breeding-dress " is well in evidence, and 

 by October is completed. This "eclipse " dress, then, answers to the 

 dull dress put on after the breeding-season by the Plovers, and is 

 simply moulted again in a month or two instead of being worn till 

 the following spring. Some of the Game-birds undergo a partial 

 *' eclipse" plumage, but this change is confined to the feathers of the 

 head and neck, as in the Grouse, Partridge, and Jungle-fowl. 



While some birds put on a new and brightly coloured dress in 

 spring, others brighten up their plumage quite as conspicuously by 

 simply shedding the tips of the feathers assumed at the autumn moult. 

 No better instance of this can be found than that of the Linnet, which, 

 by this shedding process, gains the beautiful rich brown back, and 

 rose-pink breast, that make these birds so much prized. For some 

 as yet unexplained reason, however, captive birds, if taken in July, 

 before the autumn moult, develop yellow in the place of red — which 

 colour is never regained ; if taken in the autumn, the red breast 

 appears in the following spring, but never again. The beautiful 

 plumage of the Starling is similarly attained by this method of shedding 

 the outer edges of the feathers, and the Chaffinch gains its blue head 

 in the spring by this same process. 



Whether birds can gain an access of colour to the feathers without 

 a moult is still a disputed point. Some hold that there can be no 

 doubt about the matter ; while others, apparently as well qualified to 

 speak on the subject, deny the possibility of such a change, abso- 

 lutely. 



That the colour of feathers can be influenced by feeding is a fact 

 too well known to need further comment ; but it may be interesting 

 to remark that this fact is well known to the savage people of Brazil, 



