96 NORTH AMERICAN FAUNA 61, FISH AND WILDLIFE SERVICE 



On the south side of Alaska Peninsula, our observations are 

 more scattered. Common eiders are known to nest as far east as 

 Kodiak, and at Chisik Island, in Cook Inlet, we observed at least 

 12 pairs in the spring of 1936. The local game warden assured 

 us that they nest on Duck Island nearby, and on May 13, 1937, 

 several common eiders were seen in Icy Straits — the farthest east 

 that we had observed this species. Mrs. Frank C. Hibben (1942, 

 p. 182) found them nesting in Glacier Bay, the most easterly 

 nesting record for southern Alaska. 



Gabrielson observed about 12 common eiders at Kodiak on June 

 14, 1940 ; at least 40 birds and 1 nest were seen in the Semidi Is- 

 lands on June 18; and a few were seen at Morzhovoi Bay on 

 June 21. 



As might be expected, companies of immature birds (nonbreed- 

 ers) spend the summer in the waters along Alaska Peninsula 

 and the Aleutians. Furthermore, this is the principal wintering 

 ground for the species; they do not venture farther south in any 

 great numbers. 



Nesting Habitat 



These eiders utilize a variety of nesting sites. Probably they 

 would prefer low islands of gentle slopes (such as the sand is- 

 lands of Izembek Bay) , where they can nest in the grass. In such 

 places, they nest both on the slopes and on the beach. Similar 

 situations may be found in the Aleutians — the beach of Buldir 

 Island is an example. There are few places in the Aleutians 

 where they can nest with safety on the principal shorelines be- 

 cause of the introduced blue fox. We found a few birds nesting 

 on the shores at Amchitka and Agattu, but, being adaptable, 

 they now seek the grassy tops of offshore rocks and pinnacles, 

 or islands in lakes, where they are protected by water. The 

 natives assured us that they also nest on ledges of sheer cliffs, 

 where foxes are unable to climb. 



Mortality Factors 



The blue fox is probably the most potent predator that the 

 eiders face in the Aleutians. In addition to this introduced enemy, 

 the northern bald eagle also obtains an occasional eider, but ap- 

 parently it does not prey extensively on the species. In a total 

 (taken during three seasons) of 466 food items that were identi- 

 fied in 32 eagle nests and at a few perching places, only 8 common 

 eiders are represented. In one of these instances, the eider had a 

 nest within 10 feet of an eagle's perch, and it was to be expected 

 that the eagle would eventually seize the bird. It is surprising that 

 so few eiders are taken by the eagle, because this duck does not 



