Ages to which Birds live. 25 



season, in the same peculiar key for 25 years, and was 

 considered to be the same bird, and other cases in point might 

 be cited. 



Bleached or faded birds, and birds with worn or abraded 

 plumage, are often held on that account to be very old, but 

 the truth is the colouring of a bird in perfect health and the 

 texture of its feathers are exactly the same at 50 as at five, — 

 vide Mr. Meade- Waldo^s veteran pair of Bubo maximus. 

 Neither are overgrown beaks and misshaped claws a sign of 

 age, arising in all cases from unnatural conditions of some 

 kind. An Alauda arvensis of 20 with a hind claw exceed- 

 ing 2^ inches did not owe that deformity, as its owner 

 erroneously supposes, to its age, but to captivity and un- 

 natural perches. 



Sometimes birds, after being many years in captivity, 

 have been known to develop white feathers, e. g. Turdus 

 merula (Thompson), Monticola cyanus (Macpherson), Frin- 

 gilla coelebs (Butler). But this incipient albinism is not 

 directly due to age, but to the artificial conditions under 

 which all birds are placed in captivity. In the same way, 

 when the colour of the iris grows pale, as in nocturnal and 

 diurnal birds of prey, it is much more likely to be from sun- 

 exposure than from age, though it is possibly longevity 

 which sometimes produces blindness from cataract in Bubo 

 maximus and some Psittaci. 



Now I should like to say a word about marking birds, 

 which some experimenters have thought could be made an 

 available method if placed in cai'eful hands, and it certainly 

 seems that it might be so. Nevertheless, artificial marking to 

 test age is a procedure beset with difficulties, for the chances 

 must ever be 50 to 1 against a ringed wild bird turning up 

 in the right quarter to be identified after a lapse of years. 

 The easiest species to experiment with would probably be 

 Cygnus olor, living as it does in a semi-domesticated state, 

 and C. olor has had, ever since the swanherds of the time of 

 Bacon, the reputation of antiquity. Ardea cinerea has on 

 various occasions been ringed by the Loo Hawking Club and 

 other falconers, as will appear further on, and there is one 



