138 BRITISH BIRDS. [vol. xv. 



nest of a wild duck the preceding spring, 1910. When the 

 rest of the Mallards were all in normal plumage (pinioned) 

 and paired these two birds kept by themselves and had 

 singular voices different to the normal one of the female. 

 Their bills and feet were of normal colour, but their plumage 

 was very much like that of an old drake in eclipse ; one, 

 however, showed an imperfect white ring round the neck 

 and upcurled middle tail-feathers, as well as uniform brown 

 feathers on its chin and cheeks resembling those of the 

 " lost " second juvenile plumage of the male. Dissection 

 proved that both had normal but perfectly thin and straight 

 oviducts and two little oval organs, that to the naked eye 

 looked like testes but by microscopic examination were 

 found to be ovaries in an embryonic state. 



A female Pintail shot September 17th, 1911 — judging from 

 the skeleton about sixteen-and-a-half months old — has the 

 plumage very much like the barred type of the old male in 

 eclipse, the wing, however, like that of a young male. The 

 colour of the bill was that of a normal female ; the ovary 

 (only one visible, but the bird somewhat damaged by the 

 shot) very small and undeveloped, the distal part of the 

 oviduct somewhat broad. All tail-feathers " adult," middle 

 ones somewhat elongated. 



A female Wigeon, bought on the market here, Septem- 

 ber 26th, 1918, looks like a young male going into first 

 nuptial plumage. Oviduct normal, ovary undeveloped ; 

 apparently about fifteen months old. 



In these cases the presence of a male-like plumage was 

 evidently not due to old age, but rather to arrested develop- 

 ment of the ovaries. 



In the case of the Pintail it would seem that pairing had 

 been attempted. No alteration in the tracheae was seen. 



