34 



P. C. SEKORA, G. V. BYRD, AND D. D. GIBSON 



Description of the 

 Aleutian Islands 



The Aleutian Islands form an arc that sepa- 

 rates the Bering Sea and the north Pacific 

 Ocean (Fig. 1). The island chain extends from 

 the tip of the Alaska Peninsula to within 

 483 km of the Commander Islands of Siberia. 

 The chain contains more than 200 islands 

 the peaks of a submarine volcanic mountain 

 range. Volcanic activity and earthquakes oc- 

 cur regularly. 



Weather is characterized by perpetual over- 

 cast, dense summer fog, high-velocity winds, 

 and mild temperatures with low annual and 

 diurnal variations. The sea is ice-free year- 

 round except in extremely cold winters, when 

 the arctic ice pack may reach the extreme 

 northern islands. 



The Aleutians are treeless except for a few 

 introduced, stunted spruces. Woody shrubs 

 are restricted to the most northern islands on 

 each end of the Chain. Mosses, lichens, club 

 mosses, and heaths are common ground-cover 

 plants, and taller grasses, sedges, and umbel- 

 lifers constitute the overstory. Hulten (1960) 

 provided a list of terrestrial plants found in 

 the Aleutians. Amundsen and Clebsch (1971) 

 discussed terrestrial plant ecology at Am- 

 chitka, central Aleutians. The marine plant 

 communities around the islands are fairly di- 

 verse. Lebednik et al. (1971) described marine 

 algal communities at Amchitka. 



The easternmost Aleutian island, Unimak, 

 has a mammalian fauna like that of the 

 Alaska Peninsula, including brown bear 

 (Ursus arctos), caribou (Rangifer tarandus), 

 wolf (Cam's lupus), and wolverine (Gulo gulo). 

 West of Unimak, red foxes (Vulpes fulva) oc- 

 curred historically as far as Umnak, and arc- 

 tic foxes were apparently on Attu when the 

 Russians came in 1741 (Murie 1959). Except 

 for man and dog, no land mammals occurred 

 between Umnak and Aggatu islands. Arctic 

 foxes, introduced before 1930 for fur farming, 

 still roam almost every island. Norway rats 

 (Rattus norvegicus) were introduced on many 

 islands when ships were wrecked or as a result 

 of military activities during World War II. 



Sea otters (Enhydra lutris) have repopu- 

 lated most of the Aleutians after being nearly 

 extirpated by 1900. Rookeries of Steller's sea 



lion (Eumetopias jubata) are scattered 

 throughout the Aleutians during summer, 

 and numerous harbor seals (Phoca vitulina) 

 haul out on beaches and offshore rocks. 



All five species of Pacific salmon (Oncorhyn- 

 chus spp.) occur near the islands, and at least 

 four of them (all but O. tshawytscha) spawn in 

 Aleutian streams. Dolly Varden (Salvelinus 

 malma) and threespine sticklebacks (Gas- 

 terosteus aculeatus) are found nearly every- 

 where there is fresh water. The marine envi- 

 ronment provides habitat used by at least 77 

 species of fish (Isakson et al. 1971). O'Clair 

 and Chew (1971) furnished a recent reference 

 to littoral macrofauna at Amchitka. 



About 200 species of birds have been re- 

 corded in the Aleutians (Aleutian Islands Na- 

 tional Wildlife Refuge, unpublished data). 

 Many of these are windblown stragglers from 

 both North America and Asia; only 59 species 

 breed on the islands. Although seabirds make 

 up less than half (26 species or 44%) of the 

 breeding birds, they may compose more than 

 90% of the breeding avian biomass. 



Ornithological Investigations 

 in the Aleutians 



Published ornithological information from 

 the Aleutian Islands is relatively scarce. 

 G. W. Steller, naturalist on Vitus Bering's 

 1741 expedition to Alaska, was the first per- 

 son to record ornithological information in the 

 islands (Stejneger 1936). More than a century 

 passed before W. H. Dall (1873, 1874) pub- 

 lished the next papers dealing with birds in 

 the Aleutians. In 1878, the U. S. Army Signal 

 Corps sent L. M. Turner to the Aleutians to 

 set up weather stations at several locations. 

 Turner kept notes on birds at various loca- 

 tions in the Aleutians and published two 

 papers (1885, 1886) on his observations. 

 Turner's data (1886) provided the first report 

 based on extended and widespread observa- 

 tions in the area. E. W. Nelson, who replaced 

 Turner, also provided data on birds (Nelson 

 1887). 



In 1906, A. C. Bent came to the Aleutians 

 specifically to look for birds, and he and 

 Alexander Wetmore recorded birds through- 

 out the island chain (Bent 1912). A. H. Clark 



