Response of avian bark foragers and cavity nesters to regeneration treatments in the oak-hickory forest of Northern AlabamaThis article is part of a larger document. View the larger document here.
We examined bark-foraging and cavity-nesting birds’ use of upland hardwood habitat altered through a shelterwood regeneration experiment on the mid-Cumberland Plateau of northern Alabama. The five regeneration treatments were 0, 25, 50, 75, and 100 percent basal area retention. The 75 percent retention treatment was accomplished by stem-injecting herbicide into mostly midstory canopy trees; the other removal treatments were implemented through chain saw felling and grapple skidding. Density and species composition of bark-foraging and cavity-nesting birds were monitored during the breeding season of 2002 and 2003. Signs of bark-foraging and excavation activities were examined for permanently-marked trees in vegetation sampling plots in spring and fall of 2003 and spring, 2004. A total of 11 species were detected; 9 of them established breeding territories on the study plots. Tufted Titmice were the most abundant species (1.35 ± 0.12 territories per plot per year), followed by White-breasted Nuthatch (0.67 ± 0.08 territories per plot per year) and Downy Woodpecker (0.58 ± 0.11 territories per plot per year). Species richness, abundance, and diversity indices of bark-foraging and cavity-nesting birds varied by the regeneration treatments: Clearcut had the lowest values. Interestingly, no difference was detected among the other four treatments. The amount of snags (measured as total d.b.h.) differed among the treatments: Plots that received the 75 percent retention (herbicide) treatment had the highest value. The signs of bark foraging and excavation activities (number of pecks and excavations) were positively correlated with the availability of dead trees.