Breeding Distribution and Status of Marine Birds 

 in the Aleutian Islands, Alaska 



by 



Palmer C. Sekora 1 



U. S. Fish and Wildlife Service 

 Kailua, Hawaii 



G. Vernon Byrd 2 



U. S. Fish and Wildlife Service 

 Adak, Alaska 



and 



Daniel D. Gibson 



University of Alaska 

 Fairbanks, Alaska 



Abstract 



Seabird population estimates are generally lacking for the 1,800-km-long 

 Aleutian Islands. Only the locations of the larger colonies are known, and for 

 these there are only imprecise estimates of colony sizes and often even of species 

 composition. Changes in the status of several species and populations resulting 

 from geologic and marine actions and from human intrusions are evident. Ac- 

 counts are given for 25 species of marine birds breeding in these islands. 



The 1,800-km-long chain of islands known 

 as the Aleutians provides nesting habitat for 

 various species of marine birds, including 

 three species of Pi ocellariif ormes and three of 

 cormorants (Phalacrocorax spp.), one species 

 of gull (Larus glaucescens), both kittiwake 

 species (Rissa spp.), two species of terns 

 (Sterna spp.), and at least 13 species of alcids. 



Seabird population estimates of known ac- 

 curacy are lacking for this isolated area. Loca- 

 tions of larger colonies of breeding seabirds 

 are known, however, and sufficient data are 



'Present address: U. S. Fish and Wildlife Service, 

 William L. Finley National Wildlife Refuge, Route 

 2, Box 208, Corvallis, Oregon 97330. 

 2 Present address: U. S. Fish and Wildlife Service, 

 Kilauea, Hawaii. 



available to place colonies in broad size 

 ranges. Published information on the breed- 

 ing biology of marine birds is also lacking 

 from the Aleutians, but some studies are 

 under way. The distribution of nesting marine 

 birds away from the nesting cliffs is totally 

 unknown. 



Introduced predators, primarily arctic 

 foxes (Alopex lagopus), are now found on 

 nearly every island. Breeding marine bird 

 populations have suffered drastic reductions 

 as a result. They have probably also changed 

 because of natural habitat modifications 

 caused by earthquakes, volcanic eruptions, 

 tidal waves, and marine erosion. 



The purpose of this paper is to summarize 

 the known present distribution and status of 

 breeding marine birds in the Aleutian Islands. 



33 



