Predator abundance and predation of artificial nests in natural and anthropogenic coniferous forest edges in southeast Alaska

Creation of forested edges in some landscapes can increase the risk of nest pre dation and consequently lower the reproductive success of forest passe rines. This edge effect has not been well studied in western coniferous for ests, particularly in southeast Alaska. In a series of artificial nest pred ation experiments, conducted in southeast Alaska between 1994 and 1997, we tested the risk of nest predation among open, edge, and interior forest hab itats associated with natural (wetland) and anthropogenically created (clea rcuts and suburbs) openings in coniferous north-temperate rainforest. We al so censused known (Steller's Jays [Cyanocitta stelleri] and red squirrels [ Tamiasciurus hudsonicus]) and probable nest predators (Common Ravens [Corvu s corax] and Northwestern Crows [C. caurinus]). In general, higher nest pre dation was seen in habitats with the highest abundance of nest predators. N ests in wetland forest edges, where both jays and squirrels were detected f requently, were depredated more often than those in wetland openings or for est interior, where predators were less common. High nest predation was see n on the edges of suburbs where jays and crows were abundant, and in clearc ut openings, edges, and interior forest, where squirrels were a common nest predator throughout. Type and abundance of predators differed among habita ts and possibly with degree of forest fragmentation, edge type, and forest matrix.