The Naturalist. 263 



have kept some years in captivity, from weakness, never 

 underwent a moult the first season, but retained its feathers 

 until the following autumn, when they were renewed freely. 

 This shows that their natural shedding is dependent on 

 a periodical condition of the bird, and is, moreover, in- 

 compatible with a weakly state; though, in the latter case, 

 we have already seen that, in instances where the new plu- 

 mage would have been of a diverse hue, as in the shoveller 

 before mentioned, the retained feathers become tinged with 

 the colouring secretions, as is likewise observed even when 

 they are about to be replaced. The tendency to cast the 

 feathers would thus seem to be a connected sequence of the 

 elaboration of these secretions, but requiring a more vigorous 

 state of the constitution to promote its effectuation : the im- 

 plied dependency, however, will appear unreal as we proceed. 

 Here it may be inferred, that, when a bird is moderately 

 vigorous, its seasonal change of tint may be partly induced in 

 both ways ; many of the old feathers being retained, but altered 

 in tint, to correspond with those newly put forth : for it may 

 be noticed, that as the disposition to change feathers continues 

 only for a certain period, during which it is so strong, in a 

 healthy individual, that I have even known those which had 

 been accidentally lost and renewed but a few weeks previously, 

 to be again shed and replaced by others at the regular moulting 

 time ; so, on the other hand, as in the instance mentioned of 

 the caged snowfleck, and as I have also had occasion to ob- 

 serve in other cases, when this season of natural renovation 

 has passed by, and a bird had been too weakly to renew its 

 feathers then more than in part, the remainder have been in- 

 variably retained till the next moulting period, however 

 distant. 



(Tb be continued.} 



REVIEWS. 



Art. I. The Naturalist ; illustrative of the Animal, Vegetable, 

 and Mineral Kingdoms. Edited by Neville Wood, Esq., joint 

 Editor of the " Analyst," Author of " British Song Birds," &c. 

 No. 7. Vol. II. London : Groombridge. 



The late conductors of the Naturalist, Messrs. Holl and 

 Maund, having found it expedient to resign the editorship of 

 that publication, its continuation has been undertaken by 

 Neville Wood, Esq., of ornithological celebrity ; distin- 

 guished more for the zeal and enthusiasm which he has dis- 

 played in pursuing that department of zoology, than for the 



u 4 



