British Diving Ducks 
white feathers on the breast during the first week in October). They are always, during the winter, to 
be distinguished from the mature males up to the fourth winter's moult by the presence of a certain 
amount of black or grey on the white of the upper parts. Thus a bird in its second winter has the 
lower half of the larger, and as yet imperfectly-formed, sickle-shaped, inner territories blackish, and the 
pure white of the back marred by several of the feathers having grey or blackish margins. The third 
winter, the tips only of the sickles are dark, and the grey margins on the back are much reduced in 
number. The fourth winter, as far as can be observed without handling, the bird appears adult as the 
sickles come white, and it is only on looking very closely that a few indistinct grey lines can be discerned 
on the back. Concerning the seasonal change of the male Eider, the eclipse or summer plumage may 
roughly be described as a dull black, and of a certain drake I have notes to the effect that this phase of 
plumage was commenced on May 15, completed on August 18, and lasted only a day or two, when the 
beautiful winter dress was commenced by the sides of the head becoming hoary, and completed in its 
turn on November 12. The call of the male Eider is a wild and musical Coo-00 or Ah-00, which 
can be heard at a considerable distance. They usually begin to call on assuming the nuptial dress,^ but 
become more vociferous and amorous as the breeding season approaches. 
*' With reference to the proportions of the different foods mentioned for Eiders and other diving sea- 
ducks, no fixed rule is made, but the meal constitutes their staple diet, and is usually only supplemented 
by an allowance of a few pieces of fish (chiefly herring) or animal food each bird per day ; some dis- 
cretion, however, has to be used in feeding, as it is noticeable that a too free use of these latter items 
appears too stimulating. However, it may be taken as a safe rule that it is well to supply foods of such 
a nature liberally during the moult and in severe weather, and more sparingly at other seasons ; in fact, 
in the case of established specimens that have completed their moult, 1 have found it beneficial to occa- 
sionally withhold the greater part of a meal to encourage them to take exercise in search of more 
natural food." 
In the summer of 191 2 a young Eider was reared from the egg in the Zoological 
Gardens, Regent's Park, though it is forty-three years since they possessed an example. It 
has thriven well on a diet of gentles, chopped liver, bullock's heart, and fish. 
P The males frequently begin to call in November, and continue throughout the winter in fine weather. — J. G. M.] 
