THE AUK:
A QUARTERLY JOURNAL OF
ORNITHOLOGY.
Vol. xxxvii. July, 1920. No. 3
NOTES ON SOME AMERICAN DUCKS.
BY ALLAN BROOKS
Plates XV-XVI
This contribution has been stimulated by the many valuable papers by American ornithologists on these hitherto rather neg- lected birds. Mr. Hollister's paper on the Ringneck in 'The Auk' for October 1919 is especially welcome, expressing as it does the first appreciation of the real affinities of this species. The changes that he proposes for the next A. O. U. 'Check-List' regarding the position of this duck are quite in order, but a more important one is to put the Ruddy Sheldrake where it belongs, its present position in the 'Check-List' being quite impossible. There is a great deal of work to be done yet even on the commonest of North American ducks especially with the plum- ages of the females. The variation in these is considerable. In the surface-feeding ducks it consists largely of a decrease in the spotting of the lower surface in many species. I always put this down to age but since I have found that a similar con- dition found in the larger Falcons, is really an individual variation without any change through successive moults, I am inclined to wait until observations are recorded of female ducks in captivity. The variation in the females of the diving ducks is not as a rule so pronounced, but it occurs in many species. 353
