OBSERVATIONS OF WOOD THRUSH NEST PREDATORS IN A LARGE CONTIGUOUS FOREST

摘要

We used inexpensive (<$30) cameras to document predators at active Wood Thrush (Hylo- cichla mustelina) nests in Great Smoky Mountains National Park. We observed such predators as black rat snakes (Elaphe obsoleta), American Crows (Corvus brachyrhynchos), southern flying squirrels (Glaucomys vo- lans), and black bears (Ursus americanus) remove the contents of nests. Camera instalation had no measurable effect on nest survival; daily nest survival was approximately 0.96 for nests with and without cameras. However, placement of an artificial egg trigger in the nest appeared to reduce hatching success. The immobile egg trigger might have interfered with the female Wood Thrush's ability to incubate her eggs. The variety of nest predators observed and the moderate daily survival rates recorded suggest that predation is an important constraint on Wood Thrushes nesting in large contiguous forests.