18 BULLETIN 126, UNITED STATES NATIONAL MUSEUM. 



Millais (1913) says: 



The young male during May and June molts all signs of the brilliant spring plum- 

 age, and passes into an eclipse similar to tlie adult male. It can, however, always 

 be identified by the immature wing, which is brown and slate on all its upper parts, 

 instead of being black with a large white area in the center, as in the adult male. 

 During August, September, and October the general molt toward complete winter 

 plumage is in progress, and tlie young male does not come into full dress until the 

 end of November. It may then be considered adult at 17 months. 



The fully adult plumage is worn during the winter and spring until 

 the molt into the ecKpse hegins; this sometimes begins in March and 

 proceeds verj^ slowly, but more often it does not begin until late 

 spring or early summer; it is complete in August. Millais (1913) 

 thus descril)es a specimen in full eclipse plumage taken on August 20: 



Head, neck, and upper breast almost exactly similar to adult female, but with 

 only a very short area of white on the chin; mantle and scapulars blackish brown, 

 edged with gray; v.-ings, which have just been renewed, as in winter; rump and 

 lower back a mixture, brownish ash-gray feathers like the female, and white vermicu- 

 lated with black (as in spring); flanks and sides of the chest brownish gray like the 

 female. There are a few slate and brown vermiculated feathers at the sides of the 

 vent. Under parts white, and soft parts as in spring, only not so bright. 



The molt of the ecli])se plumage begins early in September and 

 continues through October and November, or with some individuals 

 much longer; I have a specimen in my collection, taken November 7, 

 in which this molt is only fairly started; by January at the latest 

 m.ost of the males are in full plumage again. 



Of the immature females Millais (1913) says — 



in first plumage the young female is similar to the adult female, except for the less 

 abundant crest and small area of black round the eye. Tail feathers are worn and 

 wing markings less distinct. The scapular and mantle feathers, too, which remain 

 unchanged until March are like nearly all immature female ducks pale and worn on 

 their outer edges and generally gray or sandy and unlike the clean rich feathers of 

 adults. By April it is difhcult to distinguish between immature and adult females, 

 except that the young never possess the large area of black round the eye nor the 

 black feathers at tlie sides of the chin, and only the throat. The wings are as usual 

 the main character in distinguishing ago. 1 do not think these younof birds breed 

 nor are they adult until the following November.] 



Food. — The red-breasted merganser is chiofly a fish eater, but it 

 does not disdain to gather up crustaceans and mollusks. In fresh 

 water it is fond of crawfish. Its long serrated bill with the teeth 

 pointing backward is well adapted to holding its slippery prey. 

 Nelson (1887) remarks that it feeds on sticklebacks, which abound 

 in the brackish ponds of Alaska. It delights in the rapids of rivers, 

 in tidal osttiaries, and in the shallow places off sand beaches nnd at 

 the mouth of rivers, where small fish most do congregate. Strenuous 

 must be the life of the small fry in these regions when a large flock 

 of mergansers are diving together. 



