308 On Female Pheasants assuming the Male Plumage. 



about in the same manner, with the sole difference of a greater 

 celerity in the one case than in the other, so that the young male 

 will make the same progress in a certain number of months, that 

 the female requires a certain number of years to accomplish. 

 This, however, is not the case ; and it will be sufficient to com- 

 pare the descriptions of young males given by ornithologists, 

 ■with the details which I have presented with regard to old 

 females, to perceive that in either case the change is brought 

 about in a different manner; and, in fact, it can never be 

 said of an old female pheasant in which the change has com- 

 menced, that it has the plumage of a young male pheasant of 

 any particular age. Be this as it may, the observations of Man- 

 dius has already demonstrated, that female pheasants, when 

 they grow old, resemble males, — that the change of the plumage 

 is produced in a gradual manner, advancing more and more as 

 the animal grows older, — and that the ovary diminishes in size, 

 and even disappears, in several of these females with male plu- 

 mage. It might be presumed, that those in which the ovary 

 had disappeared, were those in which the change is most com- 

 plete ; but this is not the case, since that organ is not found in 

 females which resembled males but incompletely, while I found 

 it existing in one in which the resemblance was perfect. 



To these results, the observations which I have related, add 

 the following facts : that the change of plumage commences 

 much sooner in some females than in others ; that it may only 

 shew itself several years after the bird has ceased to lay, al- 

 though it must depend, more or less directly, upon this pheno- 

 menon, with which it may also coincide as to time ; that it is 

 commonly in the fourth year that the change is complete ; that 

 then the female has not only the colours, but also the brilliancy, 

 of the male, which it resembles even in the ornamental appen- 

 dages of its plumage ; that it may even acquire spurs like the 

 male ; that the transition from the dull colours to the glowing 

 tints of the adult male, is effected in a very different manner in 

 the young male, and in the adult female, although ultimately 

 the result is the same ; lastly/, that the change of plumage of 

 old females is not absolutely a general fact, and that it is not 

 even certain, because it has been observed in one genus of a 

 family ; that it occurs in the other genera of the same family. 



