PREDATION ON ARTIFICIAL NESTS IN LARGE FOREST BLOCKS

Neotropical migrant birds are declining within many forest communities in North America and concern exists regarding the impact of forest fragmentation on their breeding success, particularly with respect to nest predation. We studied predation on artificial ground nests in large forest blocks to provide information for comparison with forest fragments and to determine the importance of predator community and vegetation. From May through August 1991, we distributed 320 artificial ground nests over 8 4-ha study plots and measured 12 vegetational variables at these nests. We used remote-triggered cameras to identify predators. Nest predation rates varied from 5 to 40% among study plots. Vertical vegetational density, horizontal log density, and percent herbaceous, rock, soil, and litter cover were different (P < 0.05) between successful and unsuccessful nests. A diverse predator community, including small mammals, is responsible for loss of artificial nests and predation rates are not solely a function of forest size.