Effects of Nest Location on Depredation of Artificial Arboreal Nests

Abstract

Depredation on artificial arboreal nests was studied in 1-ha aspen (Populus spp.) plots on a ruffled grouse (Bonasa umbellus) management area in central Pennsylvania from May to August 1985. Predation was evaluated with respect to 2 factors associated with nest placement: height of nest aboveground and plot age. Americans crows (Corvus brachyrhynchos) were the major nest predator. Fewer low nests (0.5 m aboveground) were disturbed than high nests (1.5 m), and more nests were disturbed in both 8-year-old and mature plots than in 4-year-old plots. Low nests in 4-year-old plots were least susceptible to depredation. Dense shrub growth in 4-year-old plots presumably reduced the foraging efficiency of predators, thereby lowering the probability of disturbing low nests. Young clearcuts provide well-concealed mass sites for avifauna that construct nests near ground level in shrubby vegetation.