MARINE BIRDS IN THE ALEUTIAN ISLANDS, ALASKA 



35 



ATTU I. 



AfiATTU I. 



7 SEMICHI IS. 



SHEMYA I. 



BULDIR I 



UNIMAK 



SANAK I. 



u T 



A N 



|SU 



ANDREANOF IS 



RREAT ' ATKA 



SEGULA I. 



gf ' SEMISOPOCHNOI I wtm 



KISKA I. VAT IS ^ GARELOI I. TA "AGA I SITKIN I. 



X"-o 1 /, *, <J f . 

 /v 



AMCHITKA I. . KANAGA j ADAK I. 



* UMNAK I. 

 CARLISLE I 



YUNASKA 



Fig. 1. The Aleutian Islands. 



(1910) provided a valuable record of his obser- 

 vations in the Near Islands. All these workers 

 recorded birds in several locations, but none 

 provided data on more than a very few sea- 

 bird colonies. 



O. J. Murie, U. S. Biological Survey, made 

 the most complete survey of the Aleutians 

 (Murie 1959). He specifically recorded seabird 

 colonies, spending parts of four summers in 

 the area. Murie visited every large Aleutian 

 island and most small ones. He recorded 

 nearly every major colony of cliff-nesting or 

 talus-nesting seabirds known in the Aleu- 

 tians, but seldom gave sizes of colonies, and 

 separate colonies on a particular island were 

 often not differentiated. 



World War II brought several ornitholo- 

 gists to the Aleutians. Cahn (1947), Sutton 

 and Wilson (1946), Taber (1946), and Wilson 

 (1948) provided accounts of birds observed at 

 specific locations. After the war, Fish and 

 Wildlife Service personnel including I. N. 

 Gabrielson (Gabrielson and Lincoln 1959), 

 K. W. Kenyon (Kenyon 1961), and R. D. Jones 

 (Refuge Narrative Reports 1949-1970) re- 

 corded observations of breeding seabirds at 

 several locations in the Aleutians. Investiga- 

 tions associated with Atomic Energy Com- 

 mission nuclear testing at Amchitka Island 

 provided the first ecological study of avifauna 

 of an Aleutian island (White et al. 1977). Byrd 

 et al. (1974) provided a list of birds at Adak. 



In 1971, the Near Islands were surveyed by 

 U. S. Fish and Wildlife personnel in a Cape 

 Cod dory. In 1972, the Aleutian Islands Na- 

 tional Wildlife Refuge obtained a vessel, the 

 Aleutian Tern, which allowed visits to all 

 parts of the island chain. That year, nearly 



every large island as far west as Buldir was 

 visited, and seabird colonies were mapped. 

 Every island has been visited at least once 

 since 1972. 



Methods 



In estimating the current status of seabirds 

 in the Aleutians, all available data were con- 

 sidered. Most of the information used, how- 

 ever, is from surveys conducted by the U. S. 

 Fish and Wildlife Service (1970-75, unpub- 

 lished data). Because these surveys only inci- 

 dentally included Unimak, Akun, Akutan, 

 Unalaska, and Umnak islands, data for these 

 areas are almost totally lacking. Data for 

 Bogoslof, Adak, Amchitka, Buldir, Agattu, 

 Nizki, Alaid, and Attu are most accurate be- 

 cause fairly intensive investigations have 

 been conducted there since 1970. 



The available data are of unknown accu- 

 racy. The method used by most investigators 

 who have surveyed areas in the Aleutians for 

 seabird colonies has been to circle islands in a 

 ship or small boat; when a colony was en- 

 countered, they simply estimated the number 

 of birds they saw at the time. The accuracy of 

 the estimates is affected by weather, distance 

 from the colony, density of birds, ability and 

 experience of the observer, and other vari- 

 ables. Estimates of kit ti wakes and cor- 

 morants should be the most accurate, since 

 nests were actually counted. Murres (Uria 

 spp.) are readily visible on the cliffs, but the 

 percentage of breeders on the cliffs at a par- 

 ticular time of day during a particular part of 

 the breeding season is not known. Auklet 

 numbers are perhaps hardest to estimate, 



