scholarly journals The Distribution and Habitat Selection of Introduced Eastern Grey Squirrels, Sciurus carolinensis, in British Columbia

2005 ◽  
Vol 119 (3) ◽  
pp. 343 ◽  
Author(s):  
Emily K. Gonzales
Keyword(s):  
British Columbia ◽  
Habitat Selection ◽  
Coniferous Forests ◽  
Sciurus Carolinensis ◽  
Conifer Forests ◽  
Residential Land ◽  
Bodies Of Water ◽  
Land Types ◽  
Grey Squirrels ◽  
Selection Of

Eastern Grey Squirrels were first introduced to Vancouver in the Lower Mainland of British Columbia in 1909. A separate introduction to Metchosin in the Victoria region occurred in 1966. I surveyed the distribution and habitat selection of Eastern Grey Squirrels in both locales. Eastern Grey Squirrels spread throughout both regions over a period of 30 years and were found predominantly in residential land types. Some natural features and habitats, such as mountains, large bodies of water, and coniferous forests, have acted as barriers to expansion for Eastern Grey Squirrels. Given that urbanization is replacing conifer forests throughout southern British Columbia, it is predicted that Eastern Grey Squirrels will continue to spread as habitat barriers are removed.

scholarly journals Selection of Agricultural Foods by Eastern Grey Squirrels (Sciurus carolinensis): Implications for a New Introduction in British Columbia

2016 ◽  
Vol 130 (3) ◽  
pp. 202
Author(s):  
Jillian M McAllister ◽  
Valerie Law ◽  
Karl W Larsen
Keyword(s):  
British Columbia ◽  
Local Scale ◽  
Sciurus Carolinensis ◽  
Grey Squirrel ◽  
Food Items ◽  
South Central ◽  
Fruit Growing ◽  
Free Ranging ◽  
Grey Squirrels ◽  
Selection Of

The recent introduction of the Eastern Grey Squirrel (Sciurus carolinensis) into south-central British Columbia occurred within an important agricultural zone. As repercussions for the fruit-growing sector are currently unknown, we conducted trials with captive squirrels to understand the range of fruits consumed and their references. The squirrels consumed a portion of every food item offered, although the order in which the foods were used was inconsistent (with sharp contrasts between animals). Of the fruit types offered, apples appeared to be of greatest overall interest. However, seeds and nuts tended to be used first when presented in combination with fruit, suggesting opportunities to use these food types to deflect or remove Eastern Grey Squirrels from orchard crops. We caution that our results may not reflect the food items that free-ranging Eastern Grey Squirrels will target or disregard once densities in the introduced population become higher and the availability of food on a local scale begins to exert an effect.

Visual method for evaluating the state of sexual development in male grey squirrels (Sciurus carolinensis)

2006 ◽  
Vol 18 (3) ◽  
pp. 383 ◽  
Author(s):  
Mark Ferryman ◽  
Brenda A. Mayle ◽  
Geoff W. Morgan
Keyword(s):  
Sexual Development ◽  
Population Biology ◽  
Captive Breeding ◽  
Fertility Control ◽  
Sciurus Carolinensis ◽  
High Group ◽  
Visual Method ◽  
Epididymal Spermatozoa ◽  
Grey Squirrels ◽  
Selection Of

Stages of sexual development in grey squirrels were classified by scoring the presence of periscrotal hair and staining, as well as the position, size and colour of testes, to develop a visual breeding score (VBS). The VBS was a highly significant predictor of the presence and concentration of epididymal spermatozoa, which were produced from 12 months of age. Two classes of producers were identified: ‘high’ with spermatozoa levels >10 × 106 mL−1 and ‘low’ with spermatozoa levels <10 × 106 mL−1. Sperm motility was variable across all levels of productive males but was generally higher in the ‘high’ group, indicating that these were ‘functional’ males. Sexual regression was observed in two autumn periods. The VBS was less effective in determining states of regression and redevelopment; the confidence of classification improved when age class (adult or prepubertal) and date of capture was known. The use of the VBS to classify stages of sexual development in grey squirrels will improve selection of animals for studies of population biology and fertility control, and has potential application in captive breeding studies of rare Sciuridae species.

scholarly journals A Test of Interspecific Effects of Introduced Eastern Grey Squirrels, Sciurus carolinensis, on Douglas's Squirrels, Tamiasciurus douglasii, in Vancouver, British Columbia

2006 ◽  
Vol 120 (1) ◽  
pp. 10 ◽  
Author(s):  
Yeen Ten Hwang ◽  
Serge Larivière
Keyword(s):  
British Columbia ◽  
Body Mass ◽  
Home Ranges ◽  
Sciurus Carolinensis ◽  
Grey Squirrel ◽  
Negative Effects ◽  
Competition Hypothesis ◽  
Ecological Reserve ◽  
Grey Squirrels ◽  
Stanley Park

We compared the effects of absence and presence introduced Eastern Grey Squirrels (Sciurus carolinensis) on the demography of native Douglas’s Squirrels (Tamiasciurus douglasii) in two urban parks in Vancouver, British Columbia: Ecological Reserve #74 in Pacific Spirit Regional Park (Douglas’s Squirrel only) and Stanley Park (Douglas’s and Eastern Grey squirrels). Based on the exploitative competition hypothesis, we predicted that in the presence of introduced Eastern Grey squirrels, Douglas’s Squirrels would occur at lower densities, have larger home ranges, lower body mass, and poorer reproduction. Using mark-recapture methods, we found no differences in density, home range, or body mass of Douglas’s Squirrel between parks. However, the proportion of breeding Douglas’s Squirrels was higher in Ecological Reserve #74 in the absence of Eastern Grey Squirrel, than in Stanley Park. We found no evidence that Eastern Grey Squirrels are displacing Douglas’s Squirrels in Stanley Park, but less conspicuous negative effects such as reduced breeding propensity may still reflect the competitive interactions of the two squirrel species.

scholarly journals Salmon subsidies predict territory size and habitat selection of an avian insectivore

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254314
Author(s):  
Kirsten A. Wilcox ◽  
Marlene A. Wagner ◽  
John D. Reynolds
Keyword(s):  
British Columbia ◽  
Habitat Selection ◽  
Pacific Salmon ◽  
Terrestrial Ecosystems ◽  
Territory Size ◽  
Territorial Defence ◽  
Nutrient Subsidies ◽  
The Cost ◽  
Spawning Biomass ◽  
Selection Of

The annual migration and spawning event of Pacific salmon (Oncorhynchus spp.) can lead to cross-boundary delivery of marine-derived nutrients from their carcasses into adjacent terrestrial ecosystems. The densities of some passerine species, including Pacific wrens (Troglodytes pacificus), have been shown to be positively correlated with salmon abundance along streams in Alaska and British Columbia, but mechanisms maintaining these densities remain poorly understood. Riparian areas near salmon streams could provide higher quality habitat for birds through greater food availability and more suitable vegetation structure for foraging and breeding, resulting in wrens maintaining smaller territories. We examined relationships between salmon biomass and Pacific wren territory size, competition, and habitat selection along 11 streams on the coast of British Columbia, Canada. We show that male wren densities increase and territory sizes decrease as salmon-spawning biomass increases. Higher densities result in higher rates of competition as male wrens countersing more frequently to defend their territories along streams with more salmon. Wrens were also more selective of the habitats they defended along streams with higher salmon biomass; they were 68% less likely to select low-quality habitat on streams with salmon compared with 46% less likely at streams without salmon. This suggests a potential trade-off between available high-quality habitat and the cost of competition that structures habitat selection. Thus, the marine-nutrient subsidies provided by salmon carcasses to forests lead to higher densities of wrens while shifting the economics of territorial defence toward smaller territories being defended more vigorously in higher quality habitats.

Seasonal habitat selection of an expanding sika deer Cervus nippon population in eastern Hokkaido, Japan

2003 ◽  
Vol 9 (1) ◽  
pp. 141-153 ◽  
Author(s):  
Mayumi Sakuragi ◽  
Hiromasa Igota ◽  
Hiroyuki Uno ◽  
Koichi Kaji ◽  
Masami Kaneko ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Sika Deer ◽  
Cervus Nippon ◽  
Selection Of

Factors of Habitat Selection of Acheulean Sites at Ramat Yiron, Israel

Paléorient ◽  
1981 ◽  
Vol 7 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Amiel Brosh ◽  
M. Ohel
Keyword(s):  
Habitat Selection ◽  
Selection Of
Sign in / Sign up

Export Citation Format

Share Document