in which Changes of Colour are effected in Moulting, 309 



their full extent; whereas, had it changed its plumage at an 

 earlier age, this, probably, would not have been the case. It 

 is not a little singular, that the females of the mallard and 

 pintail renew their feathers in March, at which period all we 

 see are quite ragged ; while the most careful inspection fails 

 to detect any signs of a contemporaneous moult in the males : 

 in the latter, I have noticed, in numerous instances, that those 

 which, so late as this, present any appearance of the female 

 lineated markings, are uniformly in poor condition, which 

 had retarded the obliteration of them. 



Now, it is not for a moment likely that the female birds 

 should renovate their plumage without a corresponding re- 

 newal occuring in the males ; and, though it is sufficiently 

 remarkable that the latter should take place several weeks 

 (apparently even months) earlier, yet this is less improbable 

 than that the moulting should be confined to the female sex, 

 especially as the change of colour is so considerable in the 

 males. The circumstance, however (on which there can be 

 no mistake), of the middle tail-feathers having been changed, 

 is, from analogy, conclusive evidence of the whole clothing 

 plumage being likewise moulted, however the retention of 

 the feminine markings on the under parts, and, indeed, else- 

 where, might seem to induce the opposite opinion. That 

 these are gradually lost as the spring advances, without 

 another change of feather, I am perfectly certain of from 

 observation. 



The seeming discrepancy, therefore, which, on a super- 

 ficial view, appears to prevail in the mode in which different 

 species of ducks obtain the adult livery, is shown to be quite 

 dependent on the period of changing their feathers, and not, 

 as almost any one would be apt to conclude from looking at 

 them, upon some species renewing their feathers, while others 

 merely changed their colours. The earlier the moult takes 

 place, the less mature is the colouring of the new feathers, 

 and the greater, consequently, the change of hue which 

 subsequently takes place in them ; a fact which disproves the 

 supposition of any necessary connexion between the moult 

 and the mere change of colour ; while it demonstrates the 

 continued circulation pervading the pores of the feathers. Of 

 the spring-moulting species, it may be remarked, that none 

 have more mottling upon the new feathers, when first put 

 forth, than the common shieldrake; a species of which the 

 sexes only differ in intensity of tint. 



I cannot conclude this subject without adverting to another 

 seeming discordancy, which I have never had the opportunity 

 of investigating so extensively as I could wish. I shall there- 



