THE LIFE-HISTORY OF BIRDS 283 



Finally, there remain two or three curious facts concerning 

 moulting and feather growth requiring further investigation. 



It is stated that in birds which have not paired the moult 

 is considerably delayed — that is to sa}', the period between the 

 moults is increased ; and it is believed that by some means of 

 arresting the moult discovered by the Japanese, the shedding 

 of the tail feathers of a certain breed of domesticated fowl 

 is retarded until the central feathers attain a length of from 

 seventeen to eighteen feet ! This bird, which recalls the wild 

 Jungle Fowl (Galliis baiikiva), is very carefully tended, and for 

 the greater part of the day is kept tethered to a high perch 

 to prevent injury to the feathers. Once a day at least the 

 birds are taken down for exercise, and the precious train is 

 gathered up and carefully wrapped in tissue paper to prevent 

 damage, A failure to fulfil the autumn moult probably ac- 

 counts for the so-called " hairy " Water-hens that from time 

 to time occur in the country. The " hairiness " of the plumage 

 would appear to be due to the wear and abrasion of the feathers 

 from long use. 



This same question of wear and abrasion, however, requires 

 further investigation. As we have already remarked (p. 274), 

 certain birds undergo in the spring more or less of a trans- 

 formation in the coloration of the plumage assumed in the 

 autumn. Since this change of colour makes its appearance 

 more or less suddenly it would appear that something more 

 than mere wear and tear is to be sought for. The feathers 

 concerned in the change which results in the rose-pink of the 

 Linnet's breast and the black throat of the House-sparrow, 

 for example, will be found to have shed the tips of the rami at 

 a perfectly definite point, so that the feather as a whole pre- 

 serves a rounded tip, though now appreciably reduced in 

 length. 



Captive Linnets, it should be noted, for some mysterious 

 reason do not thus become red, save in cases of birds caught 

 just after the autumn moult. In the spring such birds assume 

 the normal colours proper to the season, but these never appear 

 after subsequent moults in captivity. In Madeira, on the other 

 hand, the red colour is worn throughout the year by wild birds. 

 The spotless and glossy plumage of the Common Starling is 

 similarly acquired by "abrasion," which produces the long. 



