298 DwiGHT, Plumages of the Scoters. [july 



is the best way of expressing facts and as the stages of moult and 

 of phimage overlap and it is simplest to draw an arbitrary line 

 somewhere. 



During the first winter, the knobs and bulgings of the bills of 

 males gradually appear as well as the colors that are peculiar to 

 them and to the legs and feet. The iris, brown in all females, in all 

 young birds of both sexes and in the adults of americana and nigra, 

 in males becomes pale yellow during the winter and by the end of 

 the year white in dcglandi, carbo, fmca and perspicillata. After 

 the complete first postnuptial moult in August, young birds are 

 scarcely distinguishable from adults, although in some the plumage 

 is not so black and the bills are less bulged. From now on 

 adults, both male and female, not only have a complete postnuptial 

 moult each August or September, when through simultaneous loss 

 of all the wing-quills, they lose the power of flight, but they also 

 undergo a partial prenuptial moult in ]\Iarch and April which 

 involves the body plumage and the tail, never the remiges of the 

 wings. I have yet to see an adult bird of any of the species taken 

 in the spring w^hich is not in active moult, and that this stage of 

 moult should have been completely overlooked is a matter that 

 may well surprise us. I do not find evidence of any eclipse plumage 

 in the Scoters as is claimed by a recent writer, a point to be dis- 

 cussed later. With these preliminary remarks vrhich apply indis- 

 criminately to any of the Scoters, we may take up each species 

 in turn and show the development of its plumages and moults. I 

 cite by number only such specimens as seem worthy of special 

 notice in order to fix a day or to emphasize a fact. 



Oidemia americana. 



Natal Doicn. The only specimen examined (Am. Mus. No. 

 76845, Gichiga, X. E. Siberia, Aug. 17) is one about half grown and 

 it already has acquired some of the juvenal plumage. The bird 

 seems to be indistinguishable from a younger specimen of nigra 

 (J. D., Jr. Xo. 30919, July 30) from Xorway. It is dark brown 

 above and lighter below, an indistinct collar separating the breast 

 from the still whiter chin and throat; a dark bro"«'n cap is indis- 

 tinctly outlined foreshadowing that of the next plumage. The 



