Showing papers on "Flying squirrel published in 2010"

Decline of flying and red squirrels in boreal forests revealed by long-term diet analyses of avian predators

Abstract: Conservation of species requires knowledge on population changes in time, but achieving such data in proper spatio-temporal scales can often be difficult for rare and vulnerable species. We used long-term (1950-2005) diet data of three avian predators (the nocturnal Ural and eagle owls and the diurnal goshawk) from four landscapes to study population changes of two forest-dwelling species, the Siberian flying squirrel Pteromys volans and the red squirrel Sciurus vulgaris in Finland. We also determined the role of vulnerable flying squirrel in the diet of these predators. Both squirrel species were relatively rare in the diets of the three avian predators, with the exception of red squirrel in the diet of goshawks. The Siberian flying squirrel also appears to be a less important prey for avian predators than flying squirrel species (Glaucomys spp.) are in North American forest communities. Numbers of consumed flying squirrels, but not of red squirrels, increased as the abundances of voles increased in the diets of eagle and Ural owls, that is more flying squirrels were consumed during the good vole years than the poor ones. The declining trends in the diets of three avian predators appeared to be quite similar for both studied squirrel species, possibly indicating that the process behind the decline has been the same.

Molecular systematics and Pleistocene biogeography of Mesoamerican flying squirrels

Abstract: Populations of flying squirrels from the Mesoamerican highlands represent the least understood members of the genus Glaucomys. Traditionally, these populations have been considered to be southern disjuncts of the southern flying squirrel (G. volans), a species that is widespread across the deciduous and mixed-deciduous forests of eastern North America. The limited number of museum specimens of Mesoamerican flying squirrels has made discerning the systematic and biogeographic relationships of these populations a challenge. We used ancient DNA techniques to extract, amplify, and sequence a 571-base pair segment of the mitochondrial DNA cytochrome-b gene from 22 of 34 available museum specimens. Mesoamerican flying squirrel data were combined with homologous sequences from representative populations of Glaucomys from the United States and Canada. This combined data set was analyzed using maximum-likelihood and Bayesian methods. Results indicate that G. volans is monophyletic and contains 2 monophyle...

The potential role of Strongyloides robustus on parasite-mediated competition between two species of flying squirrels (Glaucomys).

Abstract: There is growing evidence that populations of the northern flying squirrel (Glaucomys sabrinus) are declining in the eastern United States, perhaps due to competition with the southern flying squirrel (Glaucomys volans). Potential causes include parasite-mediated or apparent competition from the shared intestinal nematode, Strongyloides robustus, which has been shown to detrimentally affect the northern flying squirrel but not the southern flying squirrel. To investigate this hypothesis, we conducted a preliminary study on the parasite community of both flying squirrel species from sites in Pennsylvania where the two species occur sympatrically and where G. sabrinus is now considered endangered at the state level. We compared these parasite communities with those from northern flying squirrels from northern New York where the southern flying squirrel is absent. We found eight species of gastrointestinal parasites (Pterygodermatites peromysci, Lemuricola sciuri, Syphacia thompsoni, Syphacia spp., Capillaria spp., Citellinema bifurcatum, Strogyloides robustus, and an unidentifiable cestode species) in both species of flying squirrels examined for our study. The parasite-mediated competition hypothesis was partially supported. For example, in Pennsylvania, S. robustus was overdispersed in southern flying squirrels, such that a small proportion of the hosts carried a large proportion of the worm population. In addition, we found S. robustus to be present in northern flying squirrels when the species were sympatric, but not where southern flying squirrels were absent in New York. However, there was no association between S. robustus and the body condition of flying squirrels. We detected a potential parasite community interaction, as S. robustus abundance was positively associated with P. peromysci.

Gene flow and natal dispersal in the Siberian flying squirrel based on direct and indirect data

Abstract: Dispersal is a key determinant of the evolution and ecology of species. For a comprehensive picture of dispersal, a combination of both field observations and indirect genetic measures are required, as both of these have strengths that may mitigate the other’s limitations. Here, we used microsatellite markers and radio-telemetry data to study dispersal and gene flow in Siberian flying squirrels. Genetic data confirmed our empirical results that dispersal is female biased in the flying squirrel. Female bias in dispersal is exceptional among mammals and in flying squirrels is probably explained by competition for food resources and nesting cavities among mothers and daughters. The individual-level genetic pattern was influenced by isolation by distance. Using this information fairly comparable dispersal distances were derived using indirect data as observed directly with radio telemetry. Thus, our results support the recent conclusion that individual-level genetic data can be useful in inferring dispersal distances for species for which direct data are lacking.

Den use and selection by northern flying squirrels in fragmented landscapes.

Abstract: We studied den use and den-habitat selection by the Prince of Wales Island flying squirrel (Glaucomys sabrinus griseifrons) at multiple spatial scales in fragmented temperate rain-forest habitats because of the role dens play in the distribution, reproduction, and population density of this endemic subspecies. We observed differences in spatial patterns associated with den use between juveniles and adults: juvenile core denning areas were almost an order of magnitude larger than those of adults, and juveniles used about one-half the number of dens per month as adults. Female juveniles exhibited both the largest mean and maximum movements between consecutive dens among all age and sex classes. At the microhabitat scale of den selection snags were not selected over live trees, but flying squirrels primarily used cavities in snags and live trees. Flying squirrels also selected dens in the largest diameter live trees and snags, in snags with intermediate levels of decay, in live trees with more conks and visible bole entries, and in western hemlock (Tsuga heterophylla). At the broader scale of den selection flying squirrels chose den locations in neighborhoods with higher-volume forests and lower levels of fragmentation, although not lower absolute amounts of edge, than was available across the landscape. Our results suggest that extensive modification of landscapes from clear-cut logging and the creation of an early-seral matrix appeared to influence spatial patterns of den use in flying squirrels and den selection at the broader scale. When compared to patterns in a more-intact landscape, den selection at the microhabitat scale did not relate to differences in landscape context, suggesting additional factors might play an important role in den use across the region.

Phylogenetics of Petaurista in Light of Specimens Collected from Northern Vietnam

Abstract: The southern part of China and northern part of Indochina Peninsula is one of the hot-spots of biodiversity (e.g., Cincotta et al. 2000; Cox and Moore 2005). In this area, there are many endemic mammalian species, such as giant panda Ailuropoda melanoleuca, saola Pseudoryx nghetinhensis, Tonkin snub-nosed monkey Rhinopithecus avunculus, Inornate squirrel Callosciurus inornatus, black-eared red-backed vole Eothenomys olitor, and Yunnan hare Lepus comus (e.g., Wilson and Reeder 2005). Meijaard and Groves (2006) also found high mammalian diversity in the east side of the Mekong River including this area. Therefore, this area would be very important for the speciation and diversity of mammals in Asia. Giant flying squirrels (genus Petaurista) are widely distributed throughout South and Southeast Asia and in southern China, Taiwan, and Japan (Corbet and Hill 1992; Wilson and Reeder 2005). At present, they are split into eight species: P. alborufus, P. elegans, P. leucogenys, P. magnificus, P. nobilis, P. petaurista, P. philippensis, and P. xanthotis (Wilson and Reeder 2005). In each species, many variations and synonyms are reported (e.g., Ellerman and Morrison-Scott 1951; Corbet and Hill 1992; Wilson and Reeder 2005). In the southern China and northern Indochina Peninsula, three giant flying squirrel species (P. alborufus, P. petaurista, and P. philippensis) are commonly found (Lekagul and McNeely 1988; Corbet and Hill 1992). Based on genetic variations and morphological characteristics, in southern China, Yu et al. (2006) recognized as distinct two additional species (P. hainana from Hainan Island and P. yunanensis from Yunnan), although these species had been classified as P. philippensis by Wilson and Reeder (2005). Thus, this area may also be a biodiversity hotspot for Petaurista species. Based on molecular data, Oshida et al. (2004a) proposed that Petaurista might have some geographical evolutionary units or groups. Southern China and the northern Indochina Peninsula may be the source of one geographical evolutionary unit of Petaurista. To explore this conjecture further, we examined the phylogenetic position of two Petaurista species collected from northern Vietnam, the Indian giant flying squirrel (P. philippensis) and the spotted giant flying squirrel (P. elegans). These two forms were phylogenetically compared with those from southern China and the island of Sumatra. Here, we discuss the phylogenetic relationships of P. philippensis and P. elegans.

Nuevos registros para la ardilla voladora (Glaucomys volans) en el estado de Hidalgo, México

Abstract: Three news localities for the flying squirrel (Glaucomys volans) are added in Hidalgo, Mexico. All records are localized more to 40 km North to the one locality previously know for Hidalgo. Information suggests that flying squirrel may be a common habitant of the temperate forest of the Sierra de Pachuca, Hidalgo.

Flying Squirrel Removal Does Not Reduce Their use of Simulated Red-Cockaded Woodpecker Nest Clusters

Abstract: Reproductive success of the endangered Picoides borealis (Red-cockaded Woodpecker) is thought to be reduced by the presence of Glaucomys volans (Southern Flying Squirrels); hence, these squirrels are often removed when found inside woodpecker cavities. For this management practice to benefit Red-cockaded Woodpeckers, however, squirrel removal must both reduce the future probability of a flying squirrel re-occupying cavities and increase reproductive success for Red-cockaded Woodpeckers. In this study, using simulated Red-cockaded Woodpecker clusters (pseudo-clusters), we tested the first assumption regarding squirrels reoccupying nest cavities. We found no differences between removal and control pseudo-clusters in the amount of time that flying squirrels were present in pseudo-clusters, the proportion of nest boxes occupied by flying squirrels, or the mean number of total squirrels and individual squirrels (counting each squirrel only once in the analysis) present in the pseudo-clusters. Thus, re...

Aggressive Response of Japanese Macaques toward a Japanese Giant Flying Squirrel

Abstract: We observed 4 cases of aggressive response of Japanese macaques (Macaca fuscata) toward a Japanese giant flying squirrel (Petaurista leucogenys) at the feeding site of the Katsuyama group.When a Japanese giant flying squirrel glided over to a tree at the feeding site, almost all the adult and subadult monkeys resting around the tree mobbed the flying squirrel with threatening sounds. Immature monkeys aged ≤ 2 years screamed, and the mothers retrieved their infants immediately on spotting the flying squirrel. Several peculiar high-rank adult males and females chased, threatened, and attacked the flying squirrel for 25-114 minutes, but mothers with infants seldom approached the flying squirrel. High-ranking adult males had a greater tendency to perform agonistic displays toward the flying squirrel than low-ranking adult males and females.Our observation and previous reports about interspecific encounters suggest that Japanese macaques recognize the Japanese giant flying squirrel as being in the same category as raptors, which prey on Japanese macaques. This explains why the monkeys respond aggressively, which is typical of antipredator behavior, to the common behavioral features of the flying squirrel and raptor-gliding and descending nearby. However, this aggressive response does not seem to benefit monkeys in terms of avoiding predators because the flying squirrel is not actually a predator. There are 2 other possible benefits. Their sensitivity to behavioral features that resemble those of the raptors may improve their efficiency in terms of antipredator behavior towards actual predators such as raptors. In addition, adult or subadult male monkeys may display their fitness to potential mates by performing agonistic displays in response to the Japanese giant flying squirrel.In order to better understand the relationship between Japanese macaques and other species, it is necessary to establish a system for collecting and sharing data on rarely observed cases.