The brown creeper (Certhia americana) was recently identified as one of the forest bird species most sensitive to partial harvesting in North America. However, the processes underlying this sensitivity are poorly known. In this study, we quantified the immediate, post-treatment demographic response of this species to experimental selection harvesting in plots of northern hardwood forest in northwestern New Brunswick, Canada. We mapped individual detections and nest locations in 5 pairs (1 control and 1 treatment) of 25-ha plots in the first 2 y after single-tree selection harvesting. Linear mixed models with site and landscape context as random effects showed a significant negative effect of treatment on nest density and seasonal reproductive success. The density of large-diameter trees (≥ 30 cm dbh) was significantly lower in treated plots than in controls (mean: 77 versus 112 stems·ha-1), whereas the density of potential nesting substrates (snags with peeling bark) did not decrease significantly following treatment. Hence, the density of suitable foraging substrates may represent a limiting factor for both nest density and reproductive success, and partial harvesting may not be compatible with the persistence of breeding populations of brown creeper. Patches of untreated forest should be maintained in managed forest landscapes at all times for this and other taxa requiring old forest conditions.

Nomenclature: Marie-Victorin, 1995; American Ornithologists' Union, 2008.