Showing papers on "Flying squirrel published in 2006"

Demography of northern flying squirrels informs ecosystem management of western interior forests.

Abstract: We studied northern flying squirrel (Glaucomys sabrinus) demography in the eastern Washington Cascade Range to test hypotheses about regional and local abundance patterns and to inform managers of the possible effects of fire and fuels management on flying squirrels. We quantified habitat characteristics and squirrel density, population trends, and demography in three typical forest cover types over a four-year period. We had 2034 captures of flying squirrels over 41 000 trap nights from 1997 through 2000 and marked 879 squirrels for mark-recapture population analysis. Ponderosa pine (Pinus ponderosa) forest appeared to be poorer habitat for flying squirrels than young or mature mixed-conifer forest. About 35% fewer individuals were captured in open pine forest than in dry mixed-conifer Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis) forests. Home ranges were 85% larger in pine forest (4.6 ha) than in mixed-conifer forests (2.5 ha). Similarly, population density (Huggins estimator) in ponderosa pine forest was half (1.1 squirrels/ha) that of mixed-conifer forest (2.2 squirrels/ha). Tree canopy cover was the single best correlate of squirrel density (r = 0.77), with an apparent threshold of 55% canopy cover separating stands with low- from high-density populations. Pradel estimates of annual recruitment were lower in open pine (0.28) than in young (0.35) and mature (0.37) forest. High recruitment was most strongly associated with high understory plant species richness and truffle biomass. Annual survival rates ranged from 45% to 59% and did not vary among cover types. Survival was most strongly associated with understory species richness and forage lichen biomass. Maximum snow depth had a strong negative effect on survival. Rate of per capita increase showed a density-dependent response. Thinning and prescribed burning in ponderosa pine and dry mixed conifer forests to restore stable fire regimes and forest structure might reduce flying squirrel densities at stand levels by reducing forest canopy, woody debris, and the diversity or biomass of understory plants, truffles, and lichens. Those impacts might be ameliorated by patchy harvesting and the retention of large trees, woody debris, and mistletoe brooms. Negative stand-level impacts would be traded for increased resistance and resilience of dry-forest landscapes to now-common, large-scale stand replacement fires.

Squirrels: The Animal Answer Guide

Abstract: Did you know that a groundhog is really a type of squirrel? That squirrels control their body temperature with their tails? That most squirrels have yellow-tinted eye lenses that work like sunglasses to reduce glare? That tree squirrels can turn their hind feet completely around when climbing down a tree head-first? In Squirrels: The Animal Answer Guide, Richard W. Thorington Jr. and Katie Ferrell unveil the fascinating world of one of the "most watched" mammals on the planet. The diversity of squirrels is astounding. There are 278 species that inhabit all continents except Antarctica and Australia-varying in size from the lumbering 18-pound gray marmot to the graceful pygmy flying squirrel that is smaller than most mice. In many parts of the world they readily share human habitats, joining us for lunch in a city park, raiding our bird feeders, and sneaking into college dorm rooms through open windows. Reviled as pests or loved as an endearing amusement, squirrels have played important roles in trade, literature, and mythology. Thorington and Ferrell cover every aspect of this diverse animal family, from the first squirrels of 36 million years ago to the present day. With over one hundred photographs and an intuitive question-and-answer format, this authoritative and engaging guide sheds light on a common mammal that is anything but commonplace.

Sciurid Habitat Relationships in Forests Managed Under Selection and Shelterwood Silviculture in Ontario

Abstract: Although partial forest harvesting is practiced over large areas, managers know little about its impacts on sciurid rodents, particularly on northern (Glaucomys sabrinus) and southern flying squirrels (G. volans) in the northeastern United States and Canada. We examined habitat relationships of sciurid rodents (northern flying squirrels, southern flying squirrels, red squirrels [Tamiasciurus hudsonicus], and eastern chipmunks [Tamias striatus]) at 2 spatial scales in managed and unmanaged coniferous and hardwood forests of Algonquin Provincial Park, Ontario, Canada. We live-trapped rodents in 26 northern hardwood stands and in 16 white pine (Pinus strobus) stands from 2002 to 2004. Northern flying squirrel and red squirrel densities were significantly lower in recently harvested (3–10 yr since harvest) shelterwood stands than in unmanaged stands. In contrast, southern flying squirrel densities were higher in selection-harvested stands than in old-forest areas. The densities of northern flying squ...

Keeping tabs : Are redundant marking systems needed for rodents?

Abstract: We use survival analysis to compare failure of passive integrated transponder (PIT) tags and loss of metal ear tags in 2,277 southern flying squirrels (Glaucomys volans), 124 house mice (Mus musculus), 112 hispid cotton rats (Sigmodon hispidus), and 374 deer (Peromyscus maniculatus) and cotton mice (P. gossypinus). With the exception of cotton rats, failure rates between ear and PIT tags differed by species. Flying squirrels exhibited the highest proportional loss of both tag types and lost ear tags more readily than PIT tags failed. The opposite was true for cotton rats and deer and cotton mice. Most PIT tags appeared to fail shortly after implantation (≤3 days), except for flying squirrels and, to a lesser extent, cotton rats. Ear tags exhibited a consistent rate of loss in flying squirrels. Body mass did not influence failure of PIT tags; however, flying squirrel body mass was associated with increased loss of ear tags. For flying squirrels PIT tag failure increased with the number of times an individual had already received a PIT tag that failed. We provide recommendations for using PIT and ear tags in marking rodents based on species-specific patterns and suggest the combined use of external and internal markers to obtain the most reliable estimates of population parameters.

Distribution and relative abundance of giant squirrels and flying squirrels in Karnataka, India

Abstract: We assessed the distribution and relative abundance of giant squirrels and flying squirrels in the state of Karnataka, India. Two species of giant squirrels, the Indian giant squirrel and the grizzled giant squirrel, and two species of flying squirrel, the large brown flying squirrel and the small Travancore flying squirrel, were found to occur in Karnataka. Indian giant squirrels and large brown flying squirrels were more widely distributed than the other two species. The distributional range included the forests of the Western and Eastern Ghats. However, their distribution was confined only to forests with tall trees. Indian giant squirrels and large brown flying squirrels occur in both deciduous and evergreen forests. Small Travancore flying squirrels occupied high-rainfall evergreen forests on western slopes in the Western Ghats, and the grizzled giant squirrels occupy riverine forests. This report of the small Travancore flying squirrel is the first of this species from Karnataka, and this population is the most northern population of its distributional range. Hunting was found to be a major threat, and influenced the abundance of all species except the grizzled giant squirrel. Hunting was primarily for domestic consumption.

Role of Predator Odor in Roost Site Selection of Southern Flying Squirrels

Abstract: Roost site selection should be influenced, in part, by predator avoidance strategies. Prey species may use olfactory cues to assess predation risk. Our objective was to determine if southern flying squirrels (Glaucomys volans) use olfaction for assessing predation risk and selecting safe roosting sites. We tested the response of captive flying squirrels to several scents placed inside nest boxes. Squirrels spent significantly less time overnight in nest boxes scented with fox squirrel (Sciurus niger) fur, bobcat (Lynx rufus) fur, red fox (Vulpes vulpes) urine, raccoon (Procyon lotor) fur, king snake (Lampropeltis getula), and corn snake (Elaphe guttata) than unscented (control) boxes. Nest boxes with gray squirrel (S. carolinensis) fur, red fox urine, raccoon fur, and corn snake scent were selected as daytime roosting sites less than would be expected by chance. Southern flying squirrels are a major usurper of red-cockaded woodpecker (Picoides borealis) cavities and may reduce reproduction in this endangered bird. Our results indicate that predator odor may be an effective means of deterring flying squirrels from roost sites. If so, predator scent application could be utilized to reduce negative impacts of flying squirrels on red-cockaded woodpeckers.

Distribution and relative abundance of giant squirrels and flying squirrels in Karnataka, India / Distribution et abondance relative des espèces d'écureuils géants et volants à Karnataka, Inde

Abstract: We assessed the distribution and relative abundance of giant squirrels and flying squirrels in the state of Karnataka, India Two species of giant squirrels, the Indian giant squirrel and the grizzled giant squirrel, and two species of flying squirrel, the large brown flying squirrel and the small Travancore flying squirrel, were found to occur in Karnataka Indian giant squirrels and large brown flying squirrels were more widely distributed than the other two species The distributional range included the forests of the Western and Eastern Ghats However, their distribution was confined only to forests with tall trees Indian giant squirrels and large brown flying squirrels occur in both deciduous and evergreen forests Small Travancore flying squirrels occupied high-rainfall evergreen forests on western slopes in the Western Ghats, and the grizzled giant squirrels occupy riverine forests This report of the small Travancore flying squirrel is the first of this species from Karnataka, and this population is the most northern population of its distributional range Hunting was found to be a major threat, and influenced the abundance of all species except the grizzled giant squirrel Hunting was primarily for domestic consumption

Comparison of diets between two sympatric flying squirrel species in northern pakistan

Abstract: To test the association between body size and degree of folivory and to examine the different food habits in sympatric arboreal herbivorous mammals, we investigated diets of 2 flying squirrel species (Petaurista petaurista and Eoglaucomys fimbriatus) sympatrically distributed in the Himalayan moist temperate forest of northern Pakistan. P. petaurista and E. fimbriatus used 27 and 28 tree species, respectively. Both flying squirrel species used the same 27 tree species. However, frequency of tree species used by P. petaurista was significantly different from that used by E. fimbriatus. P. petaurista was significantly more folivorous than was E. fimbriatus. Preference of P. petaurista for leaves may be an important factor preventing competition for resources between these species. We conclude that larger body size in flying squirrels is associated with the tendency toward a foliage diet.

‘New Bornean carnivore’ is most likely a little known flying squirrel

Abstract: We analysed two camera-trap photos of an alleged new species of carnivore from Kalimantan, Borneo, Indonesia. Comparisons of the features seen in the photos with morphological features of 17 similar-looking species from the region suggest that the animal is not a new species of carnivore, as had been widely speculated, but is most likely a rarely seen species of flying squirrel, probably Aeromys thomasi. We advocate continuing adherence to the formalities of species description based on actual specimens and a formal review process. Even informal announcements about possible new species based on photographs or other indirect evidence should adopt a cautionary approach. All the possibilities should be eliminated using any available means, such as comparative morphometrics and assessments of body shape and posture, and coat colour.

Nest Boxes Reduce Flying Squirrel Use of Red-Cockaded Woodpecker Cavities

Abstract: Reproductive success of red-cockaded woodpeckers (Picoides borealis) appears to be reduced when even a single cavity in a cluster of woodpecker cavities is occupied by a southern flying squirrel (Glaucomys volans). One potential technique for reducing flying squirrel use of woodpecker cavities is the addition of nest boxes to clusters. In this study we evaluated the effects of nest boxes and red-cockaded woodpecker presence (activity) on flying squirrel use of cavities at the Joseph W. Jones Ecological Research Center in Newton, Georgia from 26 September 2002 until 26 June 2003. The interaction between presence of nest boxes and woodpecker activity significantly affected success (proportion of time no flying squirrels occupied any cavities in a cluster; F1,16 = 5.10, P = 0.04). Success was higher in active clusters with nest boxes (95%) than active clusters without nest boxes (83%) but was similar in inactive clusters (success with and without nest boxes = 78%). The proportion of cavities usurped...

Use of Fungal Rhizomorphs as Nesting Material by Glaucomys volans (Southern Flying Squirrels)

Abstract: We examined 53 nests of southern flying squirrels constructed within nest boxes in Mobile County, AL. Of those containing a bedding layer (n = 35), 80% contained fungal rhizomorphs of Marasmius brevipes. Rhizomorphs of this genus have been reported in bird-nest descriptions, but have not been documented in flying squirrel nests. M. brevipes was common on our study site, and its use by flying squirrels may be unique to the area. Nevertheless, this and similar species of rhizomorph-producing fungi occur in other portions of the flying squirrel's range, and the nondescript nature of rhizomorphs may lead to their misidentification. Our observations appear to constitute the first description of an ecological relationship between this fungus and a mammalian species.

Differential Estimates of Southern Flying Squirrel (Glaucomys Volans) Population Structure Based on Capture Method

Abstract: It is commonly assumed that population estimates derived from trapping small mammals are accurate and unbiased or that estimates derived from different capture methods are comparable. We captured southern flying squirrels (Glaucomys volans) using two methods to study their effect on red-cockaded woodpecker (Picoides borealis) reproductive success. Southern flying squirrels were captured at and removed from 30 red-cockaded woodpecker cluster sites during March to July 1994 and 1995 using Sherman traps placed in a grid encompassing a red-cockaded woodpecker nest tree and by hand from red-cockaded woodpecker cavities. Totals of 195 (1994) and 190 (1995) red-cockaded woodpecker cavities were examined at least three times each year. Trappability of southern flying squirrels in Sherman traps was significantly greater in 1995 (1.18%; 22,384 trap nights) than in 1994 (0.42%; 20,384 trap nights), and capture rate of southern flying squirrels in cavities was significantly greater in 1994 (22.7%; 502 cavity inspections) than in 1995 (10.8%; 555 cavity inspections). However, more southern flying squirrels were captured per cavity inspection than per Sherman trap night in both years. Male southern flying squirrels were more likely to be captured from cavities than in Sherman traps in 1994, but not in 1995. Both male and female juveniles were more likely to be captured in cavities than in traps in both years. In 1994 males in reproductive condition were more likely to be captured in cavities than in traps and in 1995 we captured significantly more reproductive females in cavities than in traps. Our data suggest that population estimates based solely on one trapping method may not represent true population size or structure of southern flying squirrels.

Delineating the Range of a Disjunct Population of Southern Flying Squirrels (Glaucomys volans)

Abstract: The Southern flying squirrel (Glaucomys volans) is a species designated at risk in Canada where its range is restricted to parts of Ontario, Quebec and Nova Scotia. Before this study, its distribution in Nova Scotia was poorly documented, with only seven site records. Based on live-trapping and intact and partial specimens provided by the public, we present data for 28 additional locations; these combined with historic records delineate a disjunct range that is more extensive than previously believed, but limited to southwest Nova Scotia. To identify specimens that were not fully intact, simple morphological and molecular techniques were employed. The latter, which consisted of PCR amplification and then restriction enzyme digestion of the cytochrome-b gene, allowed reliable species identification of tree squirrels from Nova Scotia by use of partial specimens.

Is there an evolutionary relict of the Japanese giant flying squirrel Petaurista leucogenys on the Asian Continent

Abstract: In the Japanese archipelago, mammalian fauna is characterized by a high degree of endemism at the species level (40% of the total) (Millien-Parra and Jaeger 1999; Abe et al. 2005). These species may have survived on the Japanese Islands after their continental populations or relatives went extinct, forming what Cronk (1997) called ‘relic endemics’ in his island biogeographical study. Some of these species may also occur on the Asian Continent, as evolutionary relicts (e.g. Imaizumi 1985). In particular, the Japanese giant flying squirrel Petaurista leucogenys (Temminck 1827) was thought to be restricted to three Japanese islands (Honshu, Shikoku, and Kyushu Islands) and a part of southwestern China (from Yunnan and eastern Tibet to Gansu), showing disjunctive distribution (e.g. Imaizumi 1985; Nowak 1991) (Fig. 1). The population in China was treated as a distinct subspecies of P. leucogenys (Ellerman and Morrison-Scott 1951). Corbet and Hill (1992) reclassified this form as a distinct species, the Chinese giant flying squirrel P. xanthotis (Milne-Edwards 1872), based on its more complex cheek-teeth and lack of a white streak in front of and below the ears. At present, this taxonomic status is broadly accepted (e.g. Wilson and Reeder 1993). Molecular systematic examination to confirm this classification, however, has never been made. If the genetic divergence between P. leucogenys and P. xanthotis is extremely low, the conspecific status of the species will be supposed. Even if their genetic divergence is high, close clustering in a phylogenetic tree should confirm the closeness of their evolutionary relationship. To test these hypotheses, molecular phylogenetic analysis was carried out using mitochondrial cytochrome b gene sequences.