150 



NORTH AMERICAN FAUNA 76 



blackbird), and numbers of others varied with the amount of recent 

 surface mining and resultant extent of tailings (e.g. , semipalmated plover, 

 wandering tattler, arctic tern) and vegetation at early states of succession 

 (e.g., varied thrush, American tree sparrow). The general effect in the 

 valley floor with the disturbance caused by mining activity was of 

 increased density but reduced diversity of birds preferring woodlands or 

 shrub habitats, and reduced density of birds more typically found in 

 mature woodland communities. 



Our data suggest high stability of raptor populations throughout the 

 study area and higher stability of populations among woodland owls than 

 open-country owls. Nesting and increased numbers of open-country owls 

 (e.g., snowy owl) were associated with lemming cycles. Populations of 

 predatory birds at the Tuluksak River tended to be stable because of the 

 complex array of habitats (and its attendant community of prey) that 

 resulted from 70 years of surface mining (Weir 1988). 



Tens of thousands of king eiders, brant, Canada geese, and emperor 

 geese use coastal estuaries and ice-free waters in the study area during 

 migration in spring and fall. Nanvak, Goodnews, and Chagvan bays are 

 obviously of extreme importance for waterfowl and shorebirds for rest- 

 ing and staging, both while waiting for nesting areas to become available 

 in spring and early in fall migration (Table 3). 



Eighteen species (10% of 185) were permanent residents (e.g., 

 gyrfalcon, ruffed grouse, downy woodpecker) during some or all years, 

 and 3 species (2%) were winter residents (common eider, king eider, 

 dark-eyed junco). All species that were considered permanent residents 

 (e.g., golden eagle, boreal owl, gray jay) and one winter resident (dark- 

 eyed junco) occurred inland, and two species were winter residents only 

 on the coast. The two coastal winter residents (common and king eiders) 

 are dependent on open water; thus, when estuaries freeze and shore-fast 

 ice forms, their winter distribution will be limited. More surveys and 

 studies in winter on the Tuluksak River and areas not previously visited 

 in winter may expand the list of permanent and winter residents. 



Forty-five species (24% of 185) were not thought to nest in the study 

 area but probably pass through each year (e.g., snow goose, Steller's 

 eider, Hudsonian godwit). Several species (e.g., black oystercatcher, 

 Bohemian waxwing, white-winged crossbill) may occur in years when 

 their populations are expanding, whereas others were out of their 

 normal range (e.g., red knot, herring gull, Kittlitz's murrelet). Most very 

 rare visitants (e.g., yellow-billed loon, Baikal teal, Terek sandpiper) were 

 birds of northern latitudes; however, frigatebirds occur in more south- 

 em latitudes. 



The Kilbuck and Ahklun mountains and their offshore islands had a 

 variety of species nesting or possibly nesting that were at the limits of 

 their normal ranges; had large numbers of some species during migration 

 on the coast; and a diversity of rare-to-very-rare visitants on the coast. 



