scholarly journals Cavity Nest Materials of Northern Flying Squirrels, Glaucomys sabrinus, and North American Red Squirrels, Tamiasciurus hudsonicus, in a Secondary Hardwood Forest of Southern Ontario

2007 ◽  
Vol 121 (3) ◽  
pp. 303 ◽  
Author(s):  
Jesse E. H. Patterson ◽  
Stephen J. Patterson ◽  
Ray J. Malcolm
Keyword(s):  
Hardwood Forest ◽  
Tamiasciurus Hudsonicus ◽  
Glaucomys Sabrinus ◽  
Red Squirrels ◽  
Southern Ontario ◽  
Flying Squirrels ◽  
Northern Flying Squirrels ◽  
Cavity Nest ◽  
North American Red Squirrels ◽  
Nest Materials

Through deployment of artificial nest boxes, we examined the composition of cavity nest materials used by Northern Flying Squirrels (Glaucomys sabrinus) and North American Red Squirrels (Tamiasciurus hudsonicus) in a secondary hardwood forest of southern Ontario, Canada. We collected 32 nests of known species association and found that 85.7% of G. sabrinus nests and 77.8% of T. hudsonicus nests were constructed almost entirely of shredded bark from Eastern White Cedar (Thuja occidentalis). Mean nest depth across all samples was 12.2 cm and showed no significant difference between species or between spring and summer nests. We review the antiparasitic properties of T. occidentalis and suggest that the use of shredded cedar bark by G. sabrinus and T. hudsonicus to line nest cavities may be a behavioural adaptation, which reduces ectoparasite loads in the nest environment.

Fungi in the winter diets of northern flying squirrels and red squirrels in the boreal mixedwood forest of northeastern Alberta

2000 ◽  
Vol 78 (12) ◽  
pp. 1514-1520 ◽  
Author(s):  
R S Currah ◽  
E A Smreciu ◽  
T Lehesvirta ◽  
M Niemi ◽  
K W Larsen
Keyword(s):  
Tamiasciurus Hudsonicus ◽  
Gut Contents ◽  
Glaucomys Sabrinus ◽  
Red Squirrels ◽  
Faecal Pellets ◽  
Flying Squirrels ◽  
Northern Flying Squirrels ◽  
Unidentified Species ◽  
Winter Diets ◽  
Northeastern Alberta

Gut contents of 138 northern flying squirrels (Glaucomys sabrinus) and 75 red squirrels (Tamiasciurus hudsonicus), which had been trapped from November to February in the boreal forest of northeastern Alberta, were examined to determine which fungi were consumed as food during the winter months in this habitat. Spores of epigeous Boletales, Russulaceae, and Cortinariaceae were most frequent and numerous. Hypogeous ascomycetes (unidentified species of Elaphomyces and Tuber) and basidiomycetes (unidentified species of Gautieria, Hymenogaster, Hysterangium, and Rhizopogon) were sometimes present in substantial amounts but were not as frequent as the remains of epigeous fungi. Guts sometimes contained remains of the tough or carbonaceous sporocarps of unidentified species of the Hymenochaetales, Diatrypaceae, Xylariaceae, and Bankeraceae. The spores of some rust fungi (e.g., Phragmidium fusiforme) along with the conidia (e.g., Helicoma sp.) and ascospores of microfungi (e.g., Sordariaceae) were also detected. Lichen tissues were absent, and this contrasts with previous suggestions that lichens are a winter food of sciurids in regions with substantial snowfall. A parallel analysis of 110 faecal pellets from northern flying squirrels collected in the same area from June to August confirms that fungi are important in its summer diet.Key words: Glaucomys sabrinus, Tamiasciurus hudsonicus, fungi, mycophagy, Sciuridae.

Modeling impacts of landscape connectivity on dispersal movements of northern flying squirrels (Glaucomys sabrinus griseifrons)

2019 ◽  
Vol 394 ◽  
pp. 44-52 ◽  
Author(s):  
Stephanie E. Trapp ◽  
Casey C. Day ◽  
Elizabeth A. Flaherty ◽  
Patrick A. Zollner ◽  
Winston P. Smith
Keyword(s):  
Landscape Connectivity ◽  
Glaucomys Sabrinus ◽  
Flying Squirrels ◽  
Northern Flying Squirrels

scholarly journals Is biasing offspring sex ratio adaptive? A test of Fisher's principle across multiple generations of a wild mammal in a fluctuating environment

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181251 ◽  
Author(s):  
Andrea E. Wishart ◽  
Cory T. Williams ◽  
Andrew G. McAdam ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Adult Sex Ratio ◽  
Secondary Sex Ratio ◽  
North American Red Squirrels ◽  
Negative Frequency Dependent Selection ◽  
Fisher’S Principle

Fisher's principle explains that population sex ratio in sexually reproducing organisms is maintained at 1 : 1 owing to negative frequency-dependent selection, such that individuals of the rare sex realize greater reproductive opportunity than individuals of the more common sex until equilibrium is reached. If biasing offspring sex ratio towards the rare sex is adaptive, individuals that do so should have more grandoffspring. In a wild population of North American red squirrels ( Tamiasciurus hudsonicus ) that experiences fluctuations in resource abundance and population density, we show that overall across 26 years, the secondary sex ratio was 1 : 1; however, stretches of years during which adult sex ratio was biased did not yield offspring sex ratios biased towards the rare sex. Females that had litters biased towards the rare sex did not have more grandoffspring. Critically, the adult sex ratio was not temporally autocorrelated across years, thus the population sex ratio experienced by parents was independent of the population sex ratio experienced by their offspring at their primiparity. Expected fitness benefits of biasing offspring sex ratio may be masked or negated by fluctuating environments across years, which limit the predictive value of the current sex ratio.

scholarly journals The effects of stress and glucocorticoids on vocalizations: a test in North American red squirrels

2019 ◽  
Vol 30 (4) ◽  
pp. 1030-1040 ◽  
Author(s):  
Matt Sehrsweeney ◽  
David R Wilson ◽  
Maggie Bain ◽  
Stan Boutin ◽  
Jeffrey E Lane ◽  
...  
Keyword(s):  
Stress State ◽  
North American ◽  
Physiological Stress ◽  
Physiological State ◽  
Public Information ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Acoustic Structure ◽  
North American Red Squirrels ◽  
Important Means

AbstractAcoustic signaling is an important means by which animals communicate both stable and labile characteristics. Although it is widely appreciated that vocalizations can convey information on labile state, such as fear and aggression, fewer studies have experimentally examined the acoustic expression of stress state. The transmission of such public information about physiological state could have broad implications, potentially influencing the behavior and life-history traits of neighbors. North American red squirrels (Tamiasciurus hudsonicus) produce vocalizations known as rattles that advertise territorial ownership. We examined the influence of changes in physiological stress state on rattle acoustic structure through the application of a stressor (trapping and handling the squirrels) and by provisioning squirrels with exogenous glucocorticoids (GCs). We characterized the acoustic structure of rattles emitted by these squirrels by measuring rattle duration, mean frequency, and entropy. We found evidence that rattles do indeed exhibit a “stress signature.” When squirrels were trapped and handled, they produced rattles that were longer in duration with a higher frequency and increased entropy. However, squirrels that were administered exogenous GCs had similar rattle duration, frequency, and entropy as squirrels that were fed control treatments and unfed squirrels. Our results indicate that short-term stress does affect the acoustic structure of vocalizations, but elevated circulating GC levels do not mediate such changes.

scholarly journals Indirect effects on fitness between individuals that have never met via an extended phenotype

2018 ◽  
Author(s):  
David N. Fisher ◽  
Jessica A. Haines ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
Jeffrey E. Lane ◽  
...  
Keyword(s):  
Population Dynamics ◽  
North American ◽  
Indirect Effects ◽  
Tamiasciurus Hudsonicus ◽  
Extended Phenotype ◽  
Red Squirrels ◽  
Lifetime Fitness ◽  
The Past ◽  
North American Red Squirrels ◽  
The Individual

AbstractInteractions between organisms are ubiquitous and have important consequences for phenotypes and fitness. Individuals can even influence those they never meet, if they have extended phenotypes which mean the environments others experience are altered. North American red squirrels (Tamiasciurus hudsonicus) guard food hoards, an extended phenotype that typically outlives the individual and is almost always inherited by non relatives. Hoarding by previous owners can therefore influence subsequent owners. We found that red squirrels bred earlier and had higher lifetime fitness if the previous owner was a male. This was driven by hoarding behaviour, as males and mid-aged squirrels had the largest hoards, and these effects persisted across owners, such that if the previous owner was male or died in mid-age subsequent occupants had larger hoards. Individuals can, therefore, influence each other’s resource dependent traits and fitness without meeting via extended phenotypes, and so the past can influence contemporary population dynamics.

Differences in trapping mortality rates of northern flying squirrels

1993 ◽  
Vol 71 (3) ◽  
pp. 660-663 ◽  
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.

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

2002 ◽  
Vol 80 (9) ◽  
pp. 1623-1633 ◽  
Author(s):  
V J Bakker ◽  
K Hastings
Keyword(s):  
Small Groups ◽  
Random Trees ◽  
High Rate ◽  
Limiting Factor ◽  
Glaucomys Sabrinus ◽  
Flying Squirrel ◽  
Flying Squirrels ◽  
Northern Flying Squirrel ◽  
Den Site Selection ◽  
Northern Flying Squirrels

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.

Genetic structure of the arboreal squirrels (Glaucomys sabrinus and Tamiasciurus hudsonicus) in the North American Black Hills

2012 ◽  
Vol 90 (9) ◽  
pp. 1191-1200 ◽  
Author(s):  
A.M. Kiesow ◽  
E.M. Monroe ◽  
H.B. Britten
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Management Practices ◽  
Allelic Diversity ◽  
Black Hills ◽  
Tamiasciurus Hudsonicus ◽  
Glaucomys Sabrinus ◽  
Red Squirrel ◽  
Isolated Populations ◽  
Red Squirrels

We selected two isolated mammalian populations, the Black Hills northern flying squirrel ( Glaucomys sabrinus (Shaw, 1801)) and red squirrel ( Tamiasciurus hudsonicus (Erxleben, 1777)), to elucidate their genetic structure. We trapped both squirrels from 2005 to 2007, in three regions of the Black Hills, differing in geology and vegetation, to collect ear samples for genetic analyses. Microsatellite loci (northern flying (9) and red squirrel (13)) were used to examine genetic structure. Data analyses estimated genetic variability, substructure, and gene flow. Northern flying and red squirrel populations have allelic diversity and observed heterozygosity similar to other isolated populations. Each species shows weak substructure from STRUCTURE and GENELAND analyses, suggesting squirrel movements may be inhibited by topography or unsuitable habitat. Recent gene flow estimates from BAYESASS indicate that both species experience some within population gene flow and red squirrels may be more structured than northern flying squirrels because of lower migration rates. Concordant patterns of genetic structure in northern flying and red squirrels indicate that other species’ movements in the Black Hills may be affected by topography and habitat. Because their habitat is isolated in the Black Hills, management practices and conservation measures are recommended to promote viability and survival of each species.

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