100 BULLETIN 130, UNITED STATES NATIONAL MUSEUM 



dress of the drakes. Native hunters say that the drakes leave the 

 coast about the last of July, but it is probable that this is apparent 

 only, and that the brown birds are females and immature birds of 

 both sexes, as well as adult drakes in the eclipse plumage. The 

 change from the eclipse to the nuptial plumage occcurs in November 

 and December and from the immature to the first nuptial dress in 

 the spring, after the 1st of March. It probably takes three years 

 before the full drake plumage is acquired, although there is con- 

 siderable variation in this. 



Eiders with V-shaped marks under the chin suggestive of 

 iSomateria v-nigra of the Pacific coast have been reported on the 

 Atlantic coast by W. A. Stearns (1883). Arthur H. Norton (1897) 

 says that "the black lancet is a character of frequent occurrence in 

 the young drakes of S. dresseri, and there are strong reasons for the 

 belief that it occurs in S. mollisima borealis.^^ He describes four 

 specimens where the mark occurs in S. dresse7'i. He states that they 

 are all immature birds and " show nothing than can be considered 

 as of a hybridic nature." 



Food. — The favorite food of the eider is the edible mussel {Mytelis 

 edulis), although various other mollusks, crustaceans, echinoderms, 

 and worms are taken with avidity. Mr. Mackay (1890) reports the 

 finding of sculpin spawn in the stomach of the eider. Such food 

 is particularly abundant around rocky ledges, and the birds gather 

 there from all sides during the day, but toward evening they fly out 

 to sea to sjjend the night. 



Behavior. — The eider is an expert diver and uses the wings under 

 water. This is evident from the fact that it flaps open the wings for 

 the first stroke. If alarmed when diving it often comes out of the 

 water flying, merely changing from subaqueous to aerial flight. 



Floating or swimming on the water, the head and neck are gen- 

 erally drawn down as if resting at ease. Wlien on the alert the neck 

 is stretched up and is much elongated. The tail is often cocked up at 

 an angle. 



The flight of the eider is generally close to the water, swift and 

 powerful, but in the absence of a head wind the bird often flaps along 

 the surface of the water for several yards before it is able to rise. 

 The neck is stretched out and the bill is pointed obliquely downward 

 at an angle of 45°, a field mark of some value in the recognition of 

 the bird. 



The speed of flight was estimated by Cartwright (1792), who 

 recorded it in his Labrador Journal, as follows : 



In my way hither I measured the flight of the eider ducks by the following 

 method, viz, on arriving off Duck Island, 6 miles distant from Henry Tickle, I 

 caused the people to lie on their oars, and when I saw the flash of the guns, 



