Territory size and ownership in red squirrels: response to removals

1986 ◽  
Vol 64 (5) ◽  
pp. 1144-1147 ◽  
Author(s):  
Karen Price ◽  
K. Broughton ◽  
S. Boutin ◽  
A. R. E. Sinclair
Keyword(s):  
Territory Size ◽  
Red Squirrel ◽  
Red Squirrels

We monitored size and ownership of red squirrel territories in the southwestern Yukon during the summer following a year of abundant cone crop. Territory boundaries were determined by observing marked individuals. Six individuals and two groups (four individuals per group) were removed to test the hypothesis that the position of territory boundaries are determined by intruder pressure. Removed squirrels were replaced by juveniles or by breeding females which had given up their former territories to their offspring. Replacement occurred within hours of the removal and territory boundaries of the new squirrels were not significantly different from those of the original territory owners. Neighbouring territorial residents did not expand their territories to occupy all or part of the vacated area. The location of territory boundaries were not affected by intruder pressure.

Seasonal changes in territory use by red squirrels, Tamiasciurus hudsonicus, and responses to food augmentation

2002 ◽  
Vol 80 (11) ◽  
pp. 1957-1965 ◽  
Author(s):  
Kara L Vlasman ◽  
John M Fryxell
Keyword(s):  
Habitat Use ◽  
Food Availability ◽  
Territory Size ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Treatment Groups ◽  
Conspecific Density ◽  
Effect Of Food ◽  
Seasonal Influences

Traditionally, the importance of food availability and intruder pressure on habitat use have been investigated through their influences on territory size. Food-augmentation studies are more prevalent; however, they are potentially confounded by the indirect effect of conspecific attraction to local food additions. Frequent ambiguous results may be attributed to the scale of investigation. Furthermore, such investigations have not considered potential seasonal influences. In this study, controlled experimental manipulations of food availability and conspecific density were performed within red squirrel (Tamiasciurus hudsonicus) territories in Algonquin Park, Ontario, to tease apart the relative importance of direct and indirect effects of food augmentation. Effects were investigated at two levels of scale, using territory size and giving-up densities (GUDs) within activity locations as response variables. Augmenting food, with or without simultaneously removing conspecifics, did not influence territory size. However, territory size decreased in control and treatment groups following manipulations, which is suggestive of seasonal influences associated with caching behaviour and midden defence. Despite overwhelming seasonal influences, GUDs were more sensitive to treatments, revealing that competitors had a greater influence on habitat use than the direct effect of food addition. Ambiguous results of previous studies may due to the use of territory-size estimators that are insensitive to responses occurring at smaller scales.

SEASONAL DAMAGE BY INSECTS AND SQUIRRELS TO FEMALE REPRODUCTIVE STRUCTURES OF BLACK SPRUCE, PICEA MARIANA (MILL.) B.S.P.

1988 ◽  
Vol 120 (12) ◽  
pp. 1113-1121 ◽  
Author(s):  
Y.H. Prévost ◽  
J.E. Laing ◽  
V.F. Haavisto
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Reproductive Structures ◽  
Cone Axis ◽  
Viable Seeds ◽  
Cone Growth

AbstractThe seasonal damage to female reproductive structures (buds, flowers, and cones) of black spruce, Picea mariana (Mill.) B.S.P., was assessed during 1983 and 1984. Nineteen insects (five Orders) and the red squirrel, Tamiasciurus hudsonicus (Erxleben), were found feeding on these reproductive structures. Collectively, these organisms damaged 88.9 and 53.5% of the cones in 1983 and 1984, respectively. In the 2 years, Lepidoptera damaged 61.8% of the cones in 1983 and 44.4% of the cones in 1984. The spruce budworm, Choristoneura fumiferana (Clem.), and the spruce coneworm, Dioryctria reniculelloides Mut. and Mun., were the most important pests. Cones damaged by Lepidoptera could be classed into three categories: (a) severe, yielding no seeds; (b) moderate, yielding 22.3 seeds per cone; and (c) light, yielding 37.5 seeds per cone. Undamaged cones yielded on average 39.9 seeds per cone. Red squirrels removed 18.8% of the cones in 1983 and none in 1984. The spruce cone axis midge, Dasineura rachiphaga Tripp, and the spruce cone maggot, Lasiomma anthracinum (Czerny), caused minor damage in both years. Feeding by spruce cone axis midge did not reduce cone growth significantly or the number of viable seeds per cone, but feeding by the spruce cone maggot did. During both years new damage by insects to the female reproductive structures of the experimental trees was not observed after mid-July. In 1983 damage by red squirrels occurred from early to late September. In 1984 damage to cones on trees treated with dimethoate was 15.6% compared with 53.5% for untreated trees, without an increase in the number of aborted cones.

A novel dicistrovirus in a captive red squirrel (Sciurus vulgaris)

2021 ◽  
Vol 102 (3) ◽  
Author(s):  
Akbar Dastjerdi ◽  
David J. Everest ◽  
Hannah Davies ◽  
Daniela Denk ◽  
Roland Zell
Keyword(s):  
Genome Organization ◽  
New Genus ◽  
Mammalian Species ◽  
Particle Morphology ◽  
Intestinal Content ◽  
Red Squirrel ◽  
Sciurus Vulgaris ◽  
Red Squirrels ◽  
The Family ◽  
Generation Sequencing

Dicistroviruses are single-stranded RNA viruses in the family Dicistroviridae. The viruses have mainly been detected in arthropods and are the cause of several devastating diseases in many of these species such as honeybees. Increasingly, dicistroviruses have also been detected in both mammalian and avian species in faeces, blood and liver, but with unconfirmed pathology. Here, we report a novel dicistrovirus detected in the intestinal content of a captive red squirrel with enteritis along with the disease history, pathology and genomic characterisation of the virus. Virus particle morphology resembled those of picornaviruses with a diameter of 28–32 nm but failed to be detected using a mammalian/avian pan viral microarray. Next-generation sequencing confirmed a dicistrovirus having a typical dicistrovirus genome organization, but with the polyprotein 1 being shorter by about 100 amino acids, compared to that of other dicistroviruses. Phylogenetic analysis of ORF1 and ORF2 sequences clustered the virus with two yet unassigned dicistroviruses detected in Gorilla gorilla and a freshwater arthropod and likely to be designated to a new genus. Our data further highlights the ever-growing diversity of dicistroviruses, but the clinical significance of the virus in mammalian species and particularly red squirrels has yet to be established.

scholarly journals The spinal nerves that constitute the brachial plexus in the red squirrel (Sciurus vulgaris)

2011 ◽  
Vol 56 (No. 8) ◽  
pp. 405-408 ◽  
Author(s):  
A. Aydin
Keyword(s):  
Brachial Plexus ◽  
Red Squirrel ◽  
Sciurus Vulgaris ◽  
Red Squirrels ◽  
Spinal Nerves

The brachial plexus in adult red squirrels (Sciurus vulgaris) was found to be formed by the rami ventralis of C5, C6, C7, C8. A thin branch of C5 and C6 constituted the cranial trunk, and the caudal trunk was formed completely by the rami ventralis of C7 and C8. Thus, in squirrels, the spinal nerves which form the brachial plexus and the joining of these spinal nerves to each other differ from other rodents and mammals.

Maturity and Viability of Seed From Squirrel-Cut Pine Cones

1987 ◽  
Vol 63 (4) ◽  
pp. 268-271 ◽  
Author(s):  
T. A. Hurly ◽  
R. J. Robertson ◽  
C. W. Yeatman
Keyword(s):  
Key Words ◽  
Scots Pine ◽  
Seed Viability ◽  
Seed Orchard ◽  
Red Squirrel ◽  
Natural Forests ◽  
Red Squirrels ◽  
Seed Maturity ◽  
Acceptable Quality ◽  
Pine Cones

The viability of pine seed from cones cached by red squirrels was compared with the viability of seed collected weekly during August and September. Scots pine seed collected during the last three weeks of August exhibited poor but increasing germinability (24.3% – 77.0%), but seed collected in September showed high germinability (95.0% – 99.5%). The strategy of collecting cones before intensive harvesting by squirrels is therefore of limited utility. Scots, red, and jack pine cones recovered from squirrel caches yielded seed of acceptable quality (greater than 80% germinability in 9 of 10 collections). Recovering cones from squirrel caches is a practical and viable strategy in seed orchards and natural forests. We recommend that collections be made within one month of harvesting by the squirrels. Key words: pine seed, seed viability, seed maturity, seed orchard red squirrel management.

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.

Body temperature dynamics of the red squirrel (Tamiasciurus hudsonicus): adaptations for energy conservation

1979 ◽  
Vol 57 (7) ◽  
pp. 1349-1354 ◽  
Author(s):  
Ronald W. Pauls
Keyword(s):  
Body Temperature ◽  
Motor Activity ◽  
Energy Conservation ◽  
Outdoor Environment ◽  
Tamiasciurus Hudsonicus ◽  
Rapid Decline ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Air Temperatures ◽  
Temperature Dynamics

Abdominal temperatures (Tb) of two captive female red squirrels (Tamiasciurus hudsonicus) in a natural outdoor environment were monitored by radiotelemetry at air temperatures (Ta) from −33 to 28 °C. Abdominal temperature ranged from 35.9 to 41.4 °C with values usually less than 39 °C when an animal was in the nest and greater than 39 °C when outside. An increase of Tb to about 39 °C usually occurred before an animal left the nest. In the nest Tb was positively correlated with Ta. Outside the nest there was a weak positive correlation at Ta less than 15 °C and a stronger negative correlation at higher Ta. During subnivean activity a rapid decline in Tb usually occurred. It is suggested that in the nest a low Tb is adaptive in that it results in energy conservation while a higher Tb is required outside the nest for rapid and coordinated motor activity.

Behavioural strategies relevant to the energy economy of the red squirrel (Tamiasciurus hudsonicus)

1978 ◽  
Vol 56 (7) ◽  
pp. 1519-1525 ◽  
Author(s):  
Ronald W. Pauls
Keyword(s):  
Locomotor Activity ◽  
Air Temperature ◽  
Activity Patterns ◽  
Tamiasciurus Hudsonicus ◽  
Temperature Cycle ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Time Out ◽  
Energy Economy ◽  
Behavioural Strategies

Amount and intensity of locomotor activity and time out of the nest were measured for a 1-year period on captive red squirrels (Tamiasciurus hudsonicus) under natural conditions. Daily and annual activity patterns and correlations between activity and meteorological variables were examined. A pronounced annual cycle, in phase with the annual temperature cycle, was found in all three aspects of activity. Daily amount of locomotor activity and time out of the nest were closely correlated with mean daily air temperature. Wind, photoperiod, and air temperature during the preceding week showed a weak but significant correlation with activity. Daily patterns of activity varied seasonally from a distinctly bimodal to a unimodal pattern, with a shift in winter to more midday activity. The relevance of these behavioural strategies to the energy economy of the red squirrel is discussed.

scholarly journals Natural strongholds for red squirrel conservation in Scotland

2021 ◽  
Vol 43 ◽  
pp. 93-108
Author(s):  
Andrew Slade ◽  
Andy White ◽  
Kenny Kortland ◽  
Peter W. W. Lurz
Keyword(s):  
Management Practice ◽  
Management Policy ◽  
Sciurus Carolinensis ◽  
Red Squirrel ◽  
Grey Squirrel ◽  
Case Scenario ◽  
Red Squirrels ◽  
Worst Case ◽  
Standard Management ◽  
Grey Squirrels

The Eurasian Red Squirrel (Sciurus vulgaris) is under threat from the invasive North American eastern Grey Squirrel (Sciurus carolinensis) with 80% of the remaining red squirrel populations in the British Isles found in Scotland. In this study we develop a spatially explicit mathematical model of the red and grey squirrel system and use it to assess the population viability of red squirrels across Scotland. In particular, we aim to identify existing forests – natural strongholds for red squirrels – that can successfully support red squirrels under UK Forestry Standard management and protect them from potential disease-mediated competition from grey squirrels. Our model results indicate that if current levels of grey squirrel control, which restrict or reduce the distribution of grey squirrels, are continued then there will be large expanses of forests in northern Scotland that support viable red squirrel populations. Model results that represent (hypothetical) scenarios where grey squirrel control no longer occurred indicated that grey squirrel range expansion and the process of red squirrel replacement would be slow. Model results for an assumed worst-case scenario where grey squirrels have expanded to all regions in Scotland identified forest regions – denoted natural strongholds – that could currently support red squirrels under UK Forestry Standard management practice. The results will be used to inform forest management policy and support a strategic review of red squirrel management by land management agencies and other stakeholders.

scholarly journals Red squirrel territorial vocalizations deter intrusions by conspecific rivals

2018 ◽  
Author(s):  
Erin Siracusa ◽  
Marina Morandini ◽  
Stan Boutin ◽  
Murray M. Humphries ◽  
Ben Dantzer ◽  
...  
Keyword(s):  
Experimental Treatment ◽  
Active Role ◽  
Control Treatment ◽  
Energy Costs ◽  
Red Squirrel ◽  
Red Squirrels ◽  
Risk Of Injury ◽  
North American Red Squirrels ◽  
Territory Owner ◽  
Paired Design

AbstractIn many species, territory defense is thought to be one of the primary functions of acoustic communication. North American red squirrels are a territorial species in which ‘rattles’ have long been thought to be the principal signal communicating territory ownership. These vocalizations have been assumed to deter intruders, thus reducing energy costs and the risk of injury associated with direct aggressive interactions. However, this hypothesis has not been directly tested. Here we used a speaker occupation experiment to test whether red squirrel rattles function to deter conspecific rivals. We studied 29 male squirrels and removed each individual from his territory twice in a paired design. During the experimental treatment we simulated the owner’s presence after its removal by broadcasting the owner’s rattle from a loudspeaker at the center of the territory once every seven minutes. During the control treatment the territory was left in silence after the temporary removal of the owner. We found that the presence of a speaker replacement reduced the probability of intrusion by 34% and increased the latency to first intrusion by 7%, providing support for the hypothesis that rattles play an active role in reducing intrusion risk. However, intrusions were not completely averted by the speaker replacement, indicating that vocalizations alone are not sufficient without other cues of the territory owner.

Sign in / Sign up

Export Citation Format

Share Document