56 BULLETIN 126, UNITED STATES NATIONAL MUSEUM. 



The colors of the upper parts, including the crown down to the bill and 

 the head stripes, vary from dark "mummy brown" to "bister" or 

 " sepia." The sides of the head, including a broad superciliary stripe, 

 are "buckthorn brown " or "honey yellow "becoming paler on the 

 throat to "light buff" or "cream buff." Similar but duller shades 

 appear on the under parts, from " Naples yellow " to " cream color," 

 shading off to dull grayish white on the belly. The inner edge of the 

 wing and the scapular and rump spots are pale yellowish buff. 



The development of the young bird to maturity is practically the 

 same as in the mallard, the sexes being indistinguishable and the 

 wings being acquired last. The growth and development of the flight 

 feathers in the young goes on simultaneously with the molt of the 

 adults, so that both reach the flight stage together in September. 

 During the first fall and perhaps for some time after that, I do not 

 know how long, young black ducks can be distinguished from old 

 birds, but during the first year, perhaps during the fall and early 

 winter, they are rapidly becoming adult in appearance. Young birds 

 during their first fall and winter may be recognized by the more 

 striped appearance of the under parts, due to the fact that the feathers 

 of the breast and belly are centrally black quite to the tip and broadly 

 edged on the sides only with brown or buff; whereas in adults these 

 feathers are very broadly dusky and only narrowly margined with 

 buff, giving the under parts a much darker appearance; the fighter 

 color of the neck is not so sharply separated from the dark colors of 

 the body in the young as in the adult; and young birds have more 

 conspicuous light edgings above and a partially immaculate chin and 

 throat. 



The age and seasonal changes in this species are not well marked 

 or conspicuous, and one can not discuss them very far without be- 

 coming hopelessly involved in the much argued, sad case of the red- 

 legged black duck, which has never been positively or even convin- 

 cingly proven or disproven. 



I have often been asked if the black duck has an eclipse plumage, 

 with the double molt common to all the surface-feeding ducks. The 

 eclipse plumage, if it had one would not be conspicuous and the double 

 molt could be detected only by dissection or close inspection. It 

 begins to molt very early in the summer and is in more or less con- 

 tinual molt for three months or more, but, as there is no necessity of 

 an eclipse plumage for concealment, I doubt if there is an actual double 

 molt. Lord William Percy, the British expert on ducks, tells me 

 that none of the ducks in which the sexes are alike have an eclipse 

 plumage; probably he is correct in this statement. The black duck 

 then has, probably, only one annual molt, the postnuptial, which is 

 prolonged and complete; the remiges are all molted at about the same 

 time, so that the bird becomes practically flightless for a while. 



