Flying squirrel

About: Flying squirrel is a research topic. Over the lifetime, 360 publications have been published within this topic receiving 5689 citations. The topic is also known as: flying squirrel.

Opportunistic Predation by a Broad-winged Hawk on a Southern Flying Squirrel

Abstract: Broad-winged Hawks (Buteo platypterus) take a wide variety of prey, including numerous small mammal species (Rusch and Doerr 1972; Fitch 1974; Mosher and Matray 1974; Rosenfield et al. 1984; and Toland 1986). Flying squirrels (Glaucomys spp.) are probably not regular prey of diurnal raptors due to the squirrel's nocturnal habits (Davis 1974); however, some overlap in raptor and squirrel activity may occur at dawn and dusk. Mosher and Matray (1974) reported a northern flying squirrel (G. sabrinus) brought to a Broad-winged Hawk nest in the Central Adirondacks in New York. Rosenfield et al. (1984) also give an account of a flying squirrel (not identified to species) being brought to a Broadwinged Hawk nest in Lincoln County, Wisconsin. No accounts of Broad-winged Hawks preying on southern flying squirrels (G. volans) have ever been documented. While climbing Red-cockaded Woodpecker (Picoides borealis) cavity trees in the Angelina National Forest in eastern Texas (3l 0 15'N, 94°l5'W), we witnessed human induced opportunistic predation by a Broad-winged Hawk on a southern flying squirrel. The incident occurred at approximately 1000 hours on 12 April 1991 in a longleaf pine (Pinus palustris) stand where we were examining cavities for occupants. RRS was climbing a tree that had two cavities at approximately 9 and 12 m above the ground. The climb required us to use four 3-m interlocking Swedish climbing ladders. As a ladder section was being put into place, two flying squirrels flushed from the lower cavity and climbed to and entered the upper cavity. At this time, an adult Broad-winged Hawk flew in and perched in a tree approximately 40 m from the cavity tree, apparently attracted by the movements of the squirrels. When RRS placed the fourth ladder section on the tree one flying squirrel flushed from the upper cavity. The hawk immediately flew from its perch and caught the squirrel in the tree's crown only 4 m above the climber's head. It then flew off out of sight with its prey.

Corticosteroid-binding globulin levels in North American sciurids: implications for the flying squirrel stress axis

Abstract: Corticosteroid-binding globulin (CBG) helps to regulate tissue bioavailability of circulating glucocorticoids (GCs), and in most vertebrates, ≥ 80-90% of GCs bind to this protein. New World flying squirrels have higher plasma total cortisol levels (the primary corticosteroid in sciurids) than most vertebrates. Recent research suggests that flying squirrels have either low amounts of CBG or CBG molecules that have a low binding affinity for cortisol, since this taxon appears to exhibit very low proportions of cortisol bound to CBG. To test whether CBG levels have been adjusted over evolutionary time, we assessed the levels of this protein in the plasma of northern (Glaucomys sabrinus Shaw, 1801) and southern (G. volans L., 1758) flying squirrels using immunoblotting, and compared the relative levels among three phylogenetically related species of sciurids. We also compared the pattern of CBG levels with cortisol levels for the same individuals. Flying squirrels had higher cortisol levels than the other spe...

Effects of trapping effort and trap placement on estimating abundance of Humboldt’s flying squirrels

Abstract: Live trapping is a common tool used to assess demography of small mammals. However, live-trapping is often expensive and stressful to captured individuals. Thus, assessing the relative tradeoffs among study goals, project expenses, and animal well-being is necessary. Here, we evaluated how apparent bias and precision of estimates for apparent annual survival, abundance, capture probability, and recapture probability of Humboldt's flying squirrels (Glaucomys oregonensis) varied with the number of secondary trapping occasions. We used data from forested sites trapped on 12 consecutive occasions annually in the HJ Andrews Experimental Forest (9 sites, 6 years) and the Siuslaw National Forest (seven sites, three years) in Oregon. We used Huggins robust design models to estimate parameters of interest for the first 4, 8, and 12 trapping occasions. We also estimated the effect of attaching Tomahawk traps to tree boles on site- and year-specific flying squirrel capture frequencies. Our estimates with 12 occasions were similar to those from previous studies. Abundances and capture probabilities were variable among years on both sites; however, variation was much lower on the Siuslaw sites. Reducing the length of primary trapping occasions from 12 to 8 nights had very little impact on parameter estimates, but further reducing the length of primary trapping occasions to four nights caused substantial apparent bias in parameter estimates and decreased precision. We found that attaching Tomahawk traps to tree boles increased the site- and year-specific capture frequency of flying squirrels. Our results suggest that live-trapping studies targeting Humboldt's flying squirrels in the Pacific Northwest of the United States could reduce per-site costs and stress to captured individuals without biasing estimates by reducing the length of primary trapping occasions to 8 nights. We encourage similar analyses for other commonly-trapped species in these and other ecosystems.