Estimating the relatedness in a population of grey squirrels Sciurus carolinensis, using DNA fingerprinting

1999 ◽  
Vol 44 ◽  
pp. 243-251 ◽  
Author(s):  
Zoë K. David-Gray ◽  
John Gurnell ◽  
David M. Hunt
Keyword(s):  
Dna Fingerprinting ◽  
Sciurus Carolinensis ◽  
Grey Squirrels

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 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.

Reinstating trophic cascades as an applied conservation tool to protect forest ecosystems from invasive grey squirrels (Sciurus carolinensis)

Food Webs ◽  
2020 ◽  
Vol 25 ◽  
pp. e00164 ◽  
Author(s):  
Jack A. Bamber ◽  
Craig M. Shuttleworth ◽  
Matthew W. Hayward ◽  
David J. Everest
Keyword(s):  
Forest Ecosystems ◽  
Trophic Cascades ◽  
Sciurus Carolinensis ◽  
Grey Squirrels

Potential impact of grey squirrels Sciurus carolinensis on woodland bird populations in England

2009 ◽  
Vol 151 (1) ◽  
pp. 211-218 ◽  
Author(s):  
Stuart E. Newson ◽  
David I. Leech ◽  
Chris M. Hewson ◽  
Humphrey Q. P. Crick ◽  
Phil V. Grice
Keyword(s):  
Sciurus Carolinensis ◽  
Bird Populations ◽  
Potential Impact ◽  
Grey Squirrels

scholarly journals Inhibitory control and memory in the search process for a modified problem in grey squirrels, Sciurus carolinensis

2019 ◽  
Vol 22 (5) ◽  
pp. 645-655 ◽  
Author(s):  
Pizza Ka Yee Chow ◽  
Stephen E. G. Lea ◽  
Natalie Hempel de Ibarra ◽  
Théo Robert
Keyword(s):  
Inhibitory Control ◽  
Search Process ◽  
Sciurus Carolinensis ◽  
Grey Squirrels
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