Depredation on artificial, avian ground nests in 1-ha aspen (Populus spp.) plots was studied on a ruffed grouse (Bonasa umbellus) management area in central Pennsylvania [USA] from April to July 1983. Predation was evaluated with respect to 2 elements of nest placement: distance from plot edge and plot age. American crows (Corvus brachyrhynchos) were the major nest predator. Avian predators rapidly associated mammalian hair-catchers, which were placed at nests to determine the identity of mammalian predators, with the location of nests. The number of total nests disturbed by predators was not related to distance of nests from edges. Nests in clear-cut plots were disturbed less by predators than those in mature plots when hair-catchers and flagging were not used at nests. The high density of small shrubs and low frequency of perch trees for avian predators in clear-cuts presumably made nests in clear-cut plots less conspicuous. Hair-catchers should not be used in studies assessing predation on nests when birds are the principal nest predators. Seasonal changes in abundance of crows, small size of plots, and relatively young age of mature plots are important factors to consider in interpreting the results of this study.