NEST-SITE SELECTION AND NESTING SUCCESS OF WOOD THRUSHES

We characterized nest sites and compared specific nest-site characteri stics to nesting success for Wood Thrushes (Hylocichla mustelina) nest ing in southeastern Pennsylvania in 1991. We determined if nests were placed in areas that differed from randomly selected points within a g iven tract of forest and compared specific nest-site characteristics f or successful nests (those that produced at least one fledgling) and n ests that failed because of predation. Wood Thrushes selected nest sit es non-randomly within a tract of forest, and female Wood Thrushes bui lt nests in areas that had a higher density of trees, higher canopy, h igher density of shrubs, and higher average shrub height than randomly selected points. Specific nest-site characteristics had little effect on the ultimate success or failure of nests. The only specific nest-s ite characteristic included in a stepwise logistic regression model co mparing successful and failed nesting attempts was the concealment of the nest from above and below. The average concealment of successful n ests was greater than unsuccessful nests, but the model that included nest concealment did not give good fit to the data. Rather, a landscap e-level feature, size of forest tract, had the greatest influence on t he success and failure of nests for Wood Thrushes in this region.