FAUNA OF THE ALEUTIAN ISLANDS AND ALASKA PENINSULA 49 



Archipelago, just short of Cross Sound." Sitka birds proved to be 

 intermediate, but closer to plumbea. 



In looking over material from the Aleutian district, it is obvious 

 that there is variation in the characters used by Grinnell and 

 Test — size and color (light or dark) — and many Aleutian speci- 

 mens are puzzling in this respect. A specimen from Kodiak is 

 similar to the Aleutian group. One from Ugashik, on the north 

 side of Alaska Peninsula, obviously is furcata. This also is true 

 for two from Nushagak. But a series from Belkofski, on the 

 Alaska Peninsula, are darker than other Aleutian specimens — 

 fully as dark as a series from Forrester Island, Stephen's Passage, 

 Sitka, and Icy Strait — though the Belkofski petrels are larger. 

 Since we are dealing with average characters, it is clear that 

 the birds from the Aleutian district, from Kodiak and Nushagak 

 west to Attu Island, should be called O.f. furcata. 



It is of interest to note that birds from the Commander Islands 

 and Kamchatka are paler and (on the average) larger than 

 • those from the Aleutian Islands. A few from the Aleutians are 

 equally large and pale, and one from as far east as Nushagak 

 is identical with many of the Kamchatka birds. These birds bear 

 out Grinnell and Test's statement of an increase in size and a 

 color transition from dark to pale, in the populations from south 

 to north and west. Probably, we should consider the Siberian 

 birds as the culmination of this trend toward larger size and 

 paler coloration, and, for the present at least, we should class 

 them with furcata of the Aleutian district. 



The forked-tailed petrel ranges widely over the North Pacific 

 and Bering Sea and is the dominant species among petrels there. 

 From May 29 to June 4, 1911, Wetmore found these birds common 

 on the Gulf of Alaska. Friedmann (1935) records several speci- 

 mens and eggs from Kodiak. Specimens have been taken at 

 Nushagak by Hanna and Johnson and have been taken at Ugashik 

 by McKay. We observed them in the Shumagin Islands and 

 found them to be abundant throughout the Aleutian chain. 

 Stejneger (1887) found them nesting in the Commander Islands. 



Nesting of this species in Bering Sea proper has not been re- 

 ported, though the bird occurs far northward. Nelson (1887) 

 found the birds off Nunivak Island in June 1877, but he speaks 

 of them chiefly as autumnal visitors, as far north as St. Lawrence 

 Island, Bering Strait, and Plover Bay, Siberia. Two specimens 

 were secured from Kotzebue Sound. According to Nelson, they 

 lingered in Bering Sea even after the formation of ice, and the 

 Eskimos told him that they were captured on the ice, near air 



