This auklet, which nests under beach boulders, in burrows, and in rock crevices, seems to use a greater variety of breeding sites than do the other auklets. The largest known colony is at Chagulak, where an estimated 10,000 were seen in 1972. Smaller colonies are found as far west as Buldir.
Crested Auklet, Least Auklet, and Whiskered Auklet (Aethia cristatella, A. pusilla, and A. pygmaea)
Aethia nest primarily in rock crevices of talus slides. Such habitat occurs locally in each major island group except the Near Islands. Least auklets outnumber crested auklets in the Aleutians, and whiskered auklets are far less common than either. Estimates of populations are probably grossly inaccurate because of the difficulty both in estimating the number of birds in the milling flocks observed and in interpreting the estimates after they are obtained.
Horned Puffin and Tufted Puffin (Fratercula corniculata and Lunda cirrhata)
Horned puffins favor rock crevices in talus slides and cliff faces for nesting, whereas tufted puffins are primarily burrow nesters. The historical distribution of the two species was probably based on availability of nesting sites, so tufted puffins were more widespread and numerous. However, in areas where extensive talus slopes are available, horned puffins reached high densities. Predation by introduced foxes may have altered the distribution of tufted puffins, which now nest primarily on fox-free islets just offshore from the larger islands where foxes occur. The distribution of horned puffins may not have been altered significantly, since they are relatively free from fox predation in their rock crevices.
Recommendations
A complete survey of the Aleutian Islands has not been done. This should be done, by methods that will provide accurate population estimates. Life history information is needed on almost all species, and data should be gathered on selected populations to determine trends. Information on winter distribution should also be compiled. The effects of introduced predators should be evaluated quantitatively, and if control measures are needed, effective, humane methods should be devised and implemented.
Acknowledgments
The authors are grateful to the following Fish and Wildlife Service personnel who helped collect previously unpublished data used in this paper: E. P. Bailey, C. S. Craighead, C. P. Dau, M. H. Dick, G. J. Divoky, R. Martin, J. L. Trapp, G. W. Watson, and C. M. White. Most of the data were collected from the deck of the Aleutian Islands National Wildlife Refuge research vessel Aleutian Tern. Captain George Putney is acknowledged for his peerless seamanship and constant encouragement; he also contributed observations of birds.
The maps were adapted from a master supplied by Elaine Rhode, Public Affairs Office, U.S. Fish and Wildlife Service, Anchorage; she also suggested the use of squares to display data. C. M. White graciously made his in-press manuscript available. W. B. Emison, R. J. Gordon, and J. L. Trapp kindly made their field notes available, and Trapp helped compile data. Most of the funds for the surveys in 1971-75 were provided by the U.S. Fish and Wildlife Service.