FAUNA OF THE ALEUTIAN ISLANDS AND ALASKA PENINSULA 161 



that these jaegers were seeking fragments of salmon left on 

 the banks by brown bears. On Buldir Island, where parasitic 

 jaegers were so numerous, a colony, of nesting glaucous-winged 

 gulls probably furnished a food supply for the jaegers. 



On Agattu Island, 24 pellets were obtained; these pellets con- 

 tained the remains of 17 forked-tailed petrels, 3 murres, and 5 

 unidentified birds. Of the last mentioned, 2 were possibly paroquet 

 auklets and 1 was a small, sparrow-sized bird. 



Some of these items, especially the murres, were undoubtedly 

 carrion. A nesting colony of forked-tailed petrels, near the 

 perch where the pellets were obtained obviously was the source 

 of the items found in the pellets — however, the method of capture 

 was not ascertained. It is, of course, possible that the jaegers 

 found parts of petrel carcasses left by blue foxes. 



Certain observations suggest that the parasitic jaeger is 

 not solely a carrion eater and robber, but that it hunts part of the 

 time in the manner of a hawk. On Semisopochnoi Island, Douglas 

 Gray and I sat on a slope in the midst of a least auklet colony 

 and watched the performance of a parasitic jaeger. For over an 

 hour, we watched the bird repeatedly pursue these little auklets 

 as the flocks came in from the sea. It did not stoop from a 

 height, but it would single out a bird and follow it as swiftly 

 as possible on the level or at various angles, in irregular flight. 

 There are two possible interpretations. It may have been trying 

 to capture an auklet, or it may have been trying to make it 

 disgorge. So far as we could see, in spite of its persistence, it 

 did not succeed in either purpose. 



Stejneger (1885) says, of the Commander Islands: "In the 

 autumn they seem to feed to a great extent on the berries of 

 Empetrum nigrum, and their excreta at that time are colored 

 dark blue." 



Stercorarius longicaudus: Long-tailed Jaeger 



Chukchi: AnkakenuadV-ukangodlin (Palmen) 



The long-tailed jaeger is rare in the Aleutian district. Fried- 

 mann (1935) records a few bones found in middens on Kodiak 

 Island. Osgood (1904) reports one on Iliamna Lake, July 16, 

 1902, and he records specimens taken by McKay at Nushagak and 

 Ugashik in July and August 1881. 



On July 17, Gabrielson recorded a long-tailed jaeger at Dilling- 

 ham; and, on July 19, he noted three on Naknek River. 



Gianini (1917) is the only observer who has reported these 

 jaegers to be common; his observations were made at Stepovak 



