Postlogging Succession and Habitat Usage of Shrubland Birds

In the first decades after logging, the vegetation structure of harvested areas changes rapidly due to succession. For shrubland birds, many of which specialize on regeneration of specific ages, the changing vegetation structure makes determining how much habitat is available for individual species difficult. We conducted a meta-analysis to determine how populations of shrubland birds in the eastern United States and Canada respond to succession in the first 20 years after timber harvest. Based on those results, we used the area under the abundance–time regression curves to estimate the proportion of regenerating forest actually used by each bird species. Of the 28 species for which we had sufficient data, 14 showed significant changes in abundance over time. For 6 species, abundance was highest immediately after logging and decreased thereafter. Abundances of 7 other species were initially low, peaked roughly 10 years after harvest, and declined thereafter. Based on these results, shrubland birds would be expected to occupy a mean of just 53% (SD = 17%) of regenerating forests up to 20 years old. Thus, current estimates of habitat availability for shrubland birds may be too high by a factor of 2. Our findings also suggest that managed openings should be maintained on longer rotations than are currently used, providing habitat for birds that prefer older regeneration.