Den trees used by northern flying squirrels (Glaucomys sabrinus) in southeastern Alaska

Northern flying squirrel (Glaucomys sabrinus) dens are reportedly associated with features characteristic of older forests, and den availability is a potential limiting factor in younger forests. We assessed den sites used by northern flying squirrels in southeastern Alaska, where we expected den-site selection to differ from more southerly forests, owing to increased thermal stress but reduced predation and competition. We located 27 squirrels in 76 dens and compared den trees with 1875 matched random trees. Most dens ([Formula: see text]73%) were in cavities and 21% were at heights of [Formula: see text]3 m. This high rate of cavity use, including cavities low in the bole, likely reflects the importance of weatherproof dens in this cool wet region. Northern flying squirrels preferentially used trees with indicators of cavity presence, selecting for snags and for larger diameter trees with bole entries, conks, abundant mistletoe, and dead tops. Although cavity availability is probably not limiting populations in this region currently, cavity-supporting trees would be one of the last elements of old-growth forests to develop in intensively logged stands. Retention of small groups of large snags and live trees exhibiting evidence of disease or physical defects would ensure availability of denning structures after logging.

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Food habits of the northern flying squirrel (Glaucomys sabrinus) in Oregon

Canadian Journal of Zoology ◽

10.1139/z85-162 ◽

1985 ◽

Vol 63 (5) ◽

pp. 1084-1088 ◽

Cited By ~ 77

Author(s):

Zane Maser ◽

Chris Maser ◽

James M. Trappe

Keyword(s):

Food Habits ◽

Food Source ◽

Coniferous Forests ◽

Glaucomys Sabrinus ◽

Hypogeous Fungi ◽

Flying Squirrel ◽

Flying Squirrels ◽

Food Items ◽

Northern Flying Squirrel ◽

Northern Flying Squirrels

Digestive tracts of 91 northern flying squirrels (Glaucomys sabrinus) were analyzed for food items; 28 were from northwestern Oregon and 63 from northeastern Oregon. Ninety percent or more of the ingested materials were fungi and lichens, including 20 genera of hypogeous fungi. The northern flying squirrel, in using hypogeous fungi as a major food source, is an important nocturnal disperser of the spores. In Oregon coniferous forests, these fungi are obligatory ectomycorrhizal symbionts with the trees in which the squirrels live.

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Differences in trapping mortality rates of northern flying squirrels

Canadian Journal of Zoology ◽

10.1139/z93-090 ◽

1993 ◽

Vol 71 (3) ◽

pp. 660-663 ◽

Cited By ~ 3

Author(s):

Daniel K. Rosenberg ◽

Robert G. Anthony

Keyword(s):

Mortality Rates ◽

Differential Mortality ◽

Glaucomys Sabrinus ◽

Adult Males ◽

Extrinsic Factors ◽

Age Cohorts ◽

Flying Squirrels ◽

Northern Flying Squirrel ◽

Northern Flying Squirrels ◽

Juvenile Males

We described trapping mortality rates of northern flying squirrel (Glaucomys sabrinus) populations in western Oregon, U.S.A., and evaluated the effects of sex, age, body mass, and number of times an individual was recaptured on these rates. Although the overall trapping mortality rates were relatively low (7%) during 16–21 day trapping sessions, we observed differential mortality rates among the sex and age cohorts. The order of mortality rates was: juvenile females (32.3%) > juvenile males (11.1%) > adult females (5.1%) = adult males (4.1%). Overall trapping mortality rates were not affected by the number of times an individual was captured. We hypothesize that the differences we found were due to extrinsic factors (weather-related) acting on differential behavioral responses to trapping and thresholds of stress an animal can tolerate.

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Fungi in the diets of northern flying squirrels and lodgepole chipmunks in the Sierra Nevada

Canadian Journal of Zoology ◽

10.1139/z05-156 ◽

2005 ◽

Vol 83 (12) ◽

pp. 1581-1589 ◽

Cited By ~ 17

Author(s):

Marc D Meyer ◽

Malcolm P North ◽

Douglas A Kelt

Keyword(s):

Sierra Nevada ◽

Glaucomys Sabrinus ◽

Dietary Overlap ◽

Conifer Forest ◽

Seasonal Differences ◽

Flying Squirrels ◽

Northern Flying Squirrel ◽

Mixed Conifer Forest ◽

Northern Flying Squirrels ◽

Teakettle Experimental Forest

The diets of a fungal specialist, northern flying squirrel (Glaucomys sabrinus (Shaw, 1801)), and a dietary generalist, lodgepole chipmunk (Neotamias speciosus (Merriam, 1890)), were examined in the old-growth, mixed-conifer forest at the Teakettle Experimental Forest in California's southern Sierra Nevada. Spores of fungi were identified from fecal pellets collected from both species during spring and summer of 1999 through 2002. Frequency of fungi in the diets of both squirrel species was consistently high across all seasons and years of study. Overall, G. sabrinus diets contained about 30% greater richness and evenness of fungal taxa than N. speciosus diets. There were no seasonal differences in richness and evenness of fungal taxa in squirrel diets. Richness of fungal taxa in diets was positively correlated with hypogeous sporocarp biomass and rainfall from June through August for N. speciosus but not for G. sabrinus. Dietary overlap between G. sabrinus and N. speciosus was high with respect to the most frequently consumed fungal taxa, although Gautieria and Gastroboletus were consumed in greater proportions by G. sabrinus than N. speciosus. Our results indicate that in the southern Sierra Nevada both G. sabrinus and N. speciosus were frequent consumers of a similar, diverse assemblage of fungal taxa and that consumption was proportional to seasonal differences in availability. For the more strongly mycophagist G. sabrinus, however, diet had a greater proportion of select fungal taxa and avoidance of less desirable taxa.

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Characteristics of northern flying squirrel populations in young second- and old-growth forests in western Oregon

Canadian Journal of Zoology ◽

10.1139/z92-023 ◽

1992 ◽

Vol 70 (1) ◽

pp. 161-166 ◽

Cited By ~ 61

Author(s):

Daniel K. Rosenberg ◽

Robert G. Anthony

Keyword(s):

Body Mass ◽

Habitat Associations ◽

Habitat Characteristics ◽

Stand Age ◽

Glaucomys Sabrinus ◽

Old Growth ◽

Flying Squirrel ◽

Flying Squirrels ◽

Northern Flying Squirrel ◽

Second Growth

We compared density, sex ratio, body mass, and annual recapture rate of northern flying squirrel (Glaucomys sabrinus) populations in second-growth and old-growth Douglas-fir (Pseudotsuga menziesii) stands in the Oregon Cascade Range. Densities averaged 2.0 and 2.3 squirrels/ha in second- and old-growth stands, respectively. Although densities varied between years within stands, average densities were similar between years. Body mass and annual recapture rate were similar between stand–age classes, although a higher proportion of females was recaptured in subsequent years in second-growth than in old-growth stands. Similarly, there was a higher proportion of females than males in second-growth but not in old-growth stands. Squirrel densities were not correlated with habitat characteristics; we concluded that flying squirrels may be habitat generalists, and not a species associated with old-growth stands, as was previously hypothesized. We suggest that studies be carried out with radiotelemetry to more accurately assess the habitat associations of this species.

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Experimental trials of the northern flying squirrel (Glaucomys sabrinus) traversing managed rainforest landscapes: perceptual range and fine-scale movements

Canadian Journal of Zoology ◽

10.1139/z08-084 ◽

2008 ◽

Vol 86 (9) ◽

pp. 1050-1058 ◽

Cited By ~ 24

Author(s):

E. A. Flaherty ◽

W. P. Smith ◽

S. Pyare ◽

M. Ben-David

Keyword(s):

Forest Edge ◽

Glaucomys Sabrinus ◽

Perceptual Range ◽

Cost Of Transport ◽

Flying Squirrel ◽

Flying Squirrels ◽

Northern Flying Squirrel ◽

Second Growth ◽

Fragmented Forests ◽

Experimental Trials

Successful dispersal in many species may be a function of the distance at which animals can perceive a particular landscape feature (i.e., perceptual range), as well as energetic costs associated with traversing the distance towards that feature. We used a model, relating perceptual range to body size of mammals, to predict the perceptual range of the northern flying squirrel ( Glaucomys sabrinus (Shaw, 1801)) in fragmented forests of Southeast Alaska. We hypothesized that the perceptual range of flying squirrels would be 325.5–356.5 m in clearcuts and 159.7–174.9 m in second-growth stands. The distance advantage in clearcuts may, however, be lost if the cost of transport in that habitat is higher. Our results suggest that as heuristically predicted by the model, the perceptual range of flying squirrels was greater in clearcut habitats than in second-growth stands. Nonetheless, for both habitats the actual perceptual range was significantly shorter than predicted by the model. We found that precipitation, and associated cloud cover and illumination, and wind speed, which affect olfaction capabilities, influenced orientation success. Although squirrels more often oriented towards the forest edge in clearcuts, they paused more often during their movements, which may lead to higher costs of dispersing through this habitat. The application of the mass-based model to nonagricultural landscapes should be done with caution, and variables such as wind and illumination be measured concurrently. Our data illustrate that dispersing squirrels likely will not venture into managed habitats because logging creates clearcuts larger than the perceptual range of these mammals.

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Implications of cytochrome b sequence variation for biogeography and conservation of the northern flying squirrels (Glaucomys sabrinus) of the Alexander Archipelago, Alaska

Canadian Journal of Zoology ◽

10.1139/z98-116 ◽

1998 ◽

Vol 76 (9) ◽

pp. 1771-1777 ◽

Cited By ~ 16

Author(s):

John R Demboski ◽

Brandy K Jacobsen ◽

Joseph A Cook

Keyword(s):

Cytochrome B ◽

Yukon Territory ◽

Base Line ◽

Glaucomys Sabrinus ◽

Southeast Alaska ◽

Flying Squirrel ◽

Flying Squirrels ◽

Mitochondrial Cytochrome B ◽

Northern Flying Squirrels ◽

Alexander Archipelago

The Alexander Archipelago of southeast Alaska is a highly fragmented landscape that is suspected to support a relatively large number of endemic mammals. At least two subspecies of northern flying squirrels (Glaucomys sabrinus) have been recognized from the region, the endemic Prince of Wales Island flying squirrel, Glaucomys sabrinus griseifrons, and the Alaska Coast flying squirrel, G. s. zaphaeus. We examined 56 northern flying squirrels from Alaska, Washington State, and Yukon Territory, using the DNA sequence from the mitochondrial cytochrome b gene to assess geographic variation. Flying squirrels from Washington were highly divergent (7.3%) from those of Alaska and Yukon Territory. Variation among Alaska and Yukon Territory populations was minimal, but five haplotypes were found. One predominantly "mainland" haplotype was widespread throughout Alaska, one island haplotype was confined to nine islands in southeast Alaska ("Prince of Wales complex"), and three haplotypes were unique. Flying squirrels of the Prince of Wales complex appear to be neoendemics and descended from a single founder population. Mitochondrial variation, although minimal, is consistent with the continued recognition of G. s. griseifrons. Our results, in light of increased habitat fragmentation in southeast Alaska, suggest that molecular data can provide important base-line information for effective management of insular populations.

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Scent marking by cheek rubbing in the northern flying squirrel (Glaucomys sabrinus)

Canadian Journal of Zoology ◽

10.1139/z83-316 ◽

1983 ◽

Vol 61 (11) ◽

pp. 2377-2380 ◽

Cited By ~ 4

Author(s):

Jean Ferron

Keyword(s):

Scent Marking ◽

Ground Squirrels ◽

Glaucomys Sabrinus ◽

Flying Squirrel ◽

Feeding Sites ◽

Flying Squirrels ◽

Northern Flying Squirrel ◽

Intraspecific Communication ◽

Marking Behaviour ◽

Ethological Study

Scent marking is relatively well documented in ground squirrels. Some work has been conducted on arboreal sciurids, but no detailed study on scent marking has yet been published on flying squirrels, a distinct subfamily of the Sciuridae. The objective of the present study is to fill this gap by analysing scent-marking behaviour by cheek rubbing in the Northern flying squirrel, Glaucomys sabrinus. The presence and importance of oral glands are demonstrated histologically, and a detailed ethological study of 78 cases of scent marking is presented. A contextual analysis, as defined by Drummond, and a comparison with other sciurids are carried out in order to understand the role played by scent marking in this semisocial species. It appears that scent marking by cheek rubbing is used by G. sabrinus to maintain the animal's familiarity with its home range by "reassuring" and orienting it in that environment. In addition, scent marking by cheek rubbing may also function in intraspecific communication, notably with regard to sharing or avoidance of the same grooming, resting, and feeding sites.

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