Nest Site Characteristics of the Endangered Northern Flying Squirrel (Glaucomys sabrinus coloratus) in Southwest Virginia

We investigated, nest site use of the federally endangered northern flying squirrel (Glaucomys sabrinus coloratus) in southwest Virginia at Mount Rogers National Recreation Area. In second-growth and old forests, number of nests used by both sexes combined was (x) over bar = 3.3 +/- 0.8 (females n = 3, (x) over bar = 2.7 +/- 0.9, males n = 8, (x) over bar = 3.7 +/- 1.2, overall range = 1-6). Nest site characteristics varied and flying squirrels used a variety of nest types including subterranean structures. We found northern flying squirrels chose larger taller nest trees regardless of nest tree type [red spruce (Picea rubens), n 3, P = 0.04, deciduous, n = 8, P = 0.02, snags, n = 3, P = 0.01] compared to the available trees of the same type within a 200 m(2) area of the nest tree. Nest sites in old forest stands (i.e., greater than or equal to125 y old) were characterized by greater downed wood (% cover/ha) that can be associated with the increased density of fungal colonies, lower snag density (n-snags/ha) that means a more open midstory for clearer glide paths, lower live-tree density (n-trees/ha) relating to clearer glide paths and lower shrub cover (% cover/ha) indicating a more open understory compared to nest sites in second-growth stands.