310 Observations on Moultin 



fore content myself with a simple statement of the facts, in 

 the desire to call attention to the subject. 



It is well known, that, in most of the Anatidae of which the 

 sexes differ, the males undergo, at midsummer, a most remark- 

 able change of colour, reassimilating to the other sex. Now 

 this, in some species, appears to be effected by a moult ; in 

 others, by a mere change of colour. 



In the common drake and pintail, every feather is cast, 

 even the primaries being then changed ; and the new plumage 

 resembles that of the female. Here, too, I have noticed that, 

 previous to the reassumption of their appropriate garb, a 

 slight tendency to regain the colours of the latter is evinced : 

 thus, in the pintail, I have seen the white lateral line of the 

 neck become tolerably defined ; no trace of this having been 

 discernible at first. It is not so generally known, however, 

 that the females, also, at this time, renovate their plumage, 

 though without any alteration of colour. When they are 

 incubating, I have invariably found, on examination, that the 

 domestic ducks are always in deep moult. 



Other species, however (and it would seem those of which 

 the young moult into the adult garb comparatively late), 

 assume the female dress at midsummer, by an alteration of 

 colour only, without renewing the feathers, as if the male 

 tints were superimposed on those of the female, and could be 

 discharged without affecting the latter ; which, indeed, seems 

 to be the case. The bay-breasted merganser is a good ex- 

 ample of this, the beautiful colours of which completely dis- 

 appear, and very rapidly ; and what may be regarded as 

 peculiarly interesting in this instance is, that, synchronously 

 with the deep bay colour on the breast being lost, leaving 

 this part white, the originally white portion of its ornamental 

 shoulder-tuft becomes mottled, with gradually increasing con- 

 fluent streaks of brown. I do not know of a more remark- 

 able change than that which then pervades the whole plumage 

 of this species. 



It would be unnecessary to treat further, on the present 

 occasion, on the seasonal changes prevalent among this in- 

 teresting tribe of birds, considering the length to which this 

 paper has been already extended. In the adults of most of 

 those species of which the young undergo a moult in spring, 

 a series of large side feathers, to throw over the closed wing 

 when swimming, is pushed forth at the period when the im- 

 mature birds are moulting; these being a great adornment 

 to them as seen alive. 



It would be ungrateful to finish this article without acknow- 

 ledging the kind assistance rendered me by Mr. Bartlett, 



