Landscape context moderates edge effects: Nesting success of wood thrushes in Central New York

Despite two decades of research into the effects of habitat fragmentation and edges on nesting birds, critical information about how edges affect the success of natural nests of Neotropical migratory songbirds breeding in heterogeneous landscapes is still missing. We studied abundance and nesting success in Wood Thrushes (Hylocichla mustelina) breeding across a heterogeneous landscape in central New York from 1998 to 2000 to test the hypothesis that edge effects on nesting passerines are stronger in fragmented than contiguous landscapes. We monitored nests to estimate nesting success in edge and interior habitats in both fragmented and contiguously forested landscapes. In contiguous landscapes, daily survival rate did not differ between edge nests (0.963) and interior nests (0.968) (??2 = 0.19, p = 0.66). In contrast, in fragmented landscapes, daily survival estimates were higher in interior (0.971) than edge (0.953) nests (??2 = 3.1, p = 0.08). Our study supports the hypothesis that landscape composition moderates edge effects on actual nests of birds but does not determine the mechanisms causing these patterns.