15S Diseases of Pheasants. 



The assumption of male plumage and other male character- 

 i sties by the female pheasant is a phenomenon that has long 

 attracted the attention of all students of natural history. As 

 far back as 1776 Hunter, in his " Animal Economy," recorded 

 the case of a pea-hen, that had produced chickens eight several 

 times, ^Yhen eleven years old assumed full male plumage, and 

 in addition had spurs resembling those of a cock ; Hunter also 

 described this change in " Philosophical Transactions," vol. Ixx., 

 p. 527, and it is also mentioned by Yarrell. Similar changes 

 of plumage have been noticed not only amongst gallinaceous 

 birds, but also in several other species. Sir J. Bland Sutton, 

 in his work on " Evolution and Disease," gives a list of over a 

 dozen kinds of birds in which the hen has been seen in the full 

 plumage of the cock. Gamekeepers generally speak of these 

 hens as " mule birds," and it is now generally accepted that 

 the assumption of male plumage is caused by or connected 

 with disease or atrophy or non-development of the normal 

 ovary. In old birds the ovary is often found to be in a state of 

 atrophy and represented by a small mass of black pigment ; 

 but in young birds the change has been noticed in those in which 

 microscopical examination has shown that the sexual 

 characters of the ovary have not been properly developed. 

 A specimen of such a case was received at the Field 

 in December, 1914, accompanied by a letter from a game- 

 keeper, in which he said : " The bird I am sending you is one 

 of a batch of 200 reared in 1913 — I first noticed it favouring 

 a cock in plumage — before it was fully grown, the most remark- 

 able feature being the darkness of the head and neck feathers 

 (no sign of a ring) and the ochreous tinge on the breast, other- 

 wise the colour was exactly that of a hen; it came unhurt through 

 the shoots, and I had it under almost daily observation until 

 we gave up feeding in April this year. This year's rearing 

 season — it began to come to the coops for food and I was able 

 to see it had no young ones with it — I watched it carefully 

 all through its moults, and was able to see its gradually increas- 

 ing hkeness to a cock, especially the well defined ring on the 



