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 fr agmentation on their breeding success, particularly with respect to ne st predation. We studied predation on artificial ground nests in large forest blocks to provide information for comparison with forest fragm ents and to determine the importance of predator community and vegetat ion. From May through August 1991, we distributed 320 artificial groun d nests over 8 4-ha study plots and measured 12 vegetational variables at these nests. We used remote-triggered cameras to identify predator s. Nest predation rates varied from 5 to 40% among study plots. Vertic al vegetational density, horizontal log density, and percent herbaceou s, rock, soil, and litter cover were different (P < 0.05) between succ essful and unsuccessful nests. A diverse predator community, including small mammals, is responsible for loss of artificial nests and predat ion rates are not solely a function of forest size.