90 



D. A. MANUWAL AND R. W. CAMPBELL 



alcid and tern numbers. The decline in auks 

 may be due to their extreme vulnerability to 

 oil pollution (Bourne 1972o, 19726; Vermeer 

 and Vermeer 1975). The Atlantic puffin, how- 

 ever, may be suffering the additional effects 

 of gull cleptoparasitism (Nettleship 1972). 

 Secondly, there seems to be an increase in gull 

 populations on both sides of the Atlantic, par- 

 ticularly the herring gull and black-legged 

 kittiwake. 



Compared with the Atlantic coast of North 

 America and northern Europe, the data base 

 for seabird populations of the Pacific coast is 

 poor. The fragmentary evidence now available 

 indicates that there may be small population 

 increases in the western and glaucous-winged 

 gulls and range extensions of the Brandt's 

 and double-crested cormorants and of the 

 rhinoceros auklet (Scott et al. 1974). Whether 

 these changes represent actual population in- 

 creases or displacements remains unclear. The 

 remote locations of most of the large Pacific 

 seabird colonies may provide unofficial pro- 

 tection from human interference. Intensive 

 surveys are needed to establish base-line in- 

 ventories in these areas. 



As a consequence of this first comprehen- 

 sive review of the status of breeding marine 

 birds of the northeast Pacific coast of North 

 America, we recommend the following future 

 research topics as necessary for the conserva- 

 tion of this great international resource. 



Seabird colony census techniques should 

 be refined since almost 68% of the seabirds 

 in this area are nocturnal and nest in bur- 

 rows. The present reliance on aerial census- 

 ing, although economical, is inadequate to 

 census most breeding seabird populations; 

 more on-site surveys are needed. For sur- 

 face-nesting species and diurnal, burrow- 

 ing species, studies on species specific ac- 

 tivity cycles are needed so that census data 

 can be corrected for birds not observed at 

 the colony. For nocturnal, burrowing 

 species seasonal burrow occupancy rates 

 must be determined so that burrow counts 

 can be corrected for inactive burrows. 



Comprehensive surveys should be made 

 every 3-5 years. 



In 1980 a coordinated breeding bird survey 

 of the entire Pacific coasts of Mexico, 

 Canada, and the United States should be 

 conducted. 



Specific islands where key populations 

 exist should be carefully monitored for 

 subtle changes in population density or 

 species composition. 



Increased study of the breeding biology of 

 seabirds should be carried out so that base- 

 line reproductive characteristics can be 

 determined. 



Detailed studies of the effects of human 

 disturbance should be made, especially for 

 species that breed near large coastal cities 

 or marine recreation areas. 



References 



Bailey, E. P. 1973. Discovery of a Kittlitz's murre- 

 let nest. Condor 75:457. 



Binford, L., B. Elliott, and S. Singer. 1975. Dis- 

 covery of a nest and the downy young of the 

 marbled murrelet. Wilson Bull. 87:303-319. 



Bourne, W. 1972a. The decline of auks in Great 

 Britain. Biol. Conserv. 4:144-146. 



Bourne, W. 19726. Threats to seabirds. Int. Counc. 

 Bird Preserv. Bull. XI:200-218. 



Couch, L. 1929. Introduced European rabbits in the 

 San Juan Islands, Washington. J. Mammal. 

 10:334-336. 



Drent, R. H., and C. Guiguet. 1961. A catalogue of 

 British Columbia seabird colonies. Occas. Pap. 

 B. C. Prov. Mus. 12. 173 pp. 



Franklin, J., and C. Dyrness. 1973. Natural vegeta- 

 tion of Oregon and Washington. U. S. For. Serv. 

 Gen. Tech. Rep. PNW-8. 417 pp. 



Gabrielson, I., and F. Lincoln. 1959. The birds of 

 Alaska. The Stackpole Company, Harrisburg, 

 Penn., and Wildlife Management Institute, 

 Washington, D. C. 922 pp. 



Grinnell, J. 1897. Petrels of Sitka, Alaska. 

 Nidologist 4:76-78. 



Grinnell, J. 1898. Summer birds of Sitka, Alaska. 

 Auk 15:122-131. 



Grinnell, J. 1909. Birds and mammals of the 1907 

 Alexander Expedition to southeastern Alaska. 

 Univ. Calif. Publ. Zool. 5:171-264. 



Guiguet, C. 1971. A list of seabird nesting sites in 

 Barkley Sound, British Columbia. Syesis 4:253- 

 259. 



Harris, M. P. 1970. Rates and causes of increases of 

 some British gull populations. Bird Study 17:325- 

 335. 



Heath, H. 1915. Birds observed on Forrester Is- 

 land, Alaska during the summer of 1913. Condor 

 17:20-41. 



James-Veitch, E., and E. Booth. 1954. Behavior and 

 life history of the glaucous-winged gull. Walla 

 Walla Coll., Publ. Biol. 12. 



Jewett, S., W. Taylor, W. Shaw, and J. Aldrich. 

 1953. Birds of Washington State. Univ. of Wash- 

 ington Press, Seattle. 767 pp. 



