A critical look at conserving the British Red Squirrel <i>Sciurus vulgaris</i>

Gurnell, John; Pepper, Harry

doi:10.1111/j.1365-2907.1993.tb00424.x

Cited by 109 publications

(117 citation statements)

References 13 publications

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“…Grey squirrels compete with native red squirrels (Sciurus vulgaris) and have replaced them throughout much of Britain and Ireland (Lloyd 1983;Gurnell 1987;Gurnell & Pepper 1993, O'Teangana et al 2000. Without effective control, they will potentially do the same in Italy (Currado 1998;Bertolino et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Feeding of grey squirrels (Sciurus carolinensis) with the contraceptive agent DiazaCon™: effect on cholesterol, hematology, and blood chemistry

Yoder

Mayle

Furcolow

et al. 2011

Integrative Zoology

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Grey squirrels (Sciurus carolinensis) are an invasive species in Britain and Italy. They have replaced native red squirrels (Sciurus vulgaris) throughout most of Britain, and cause damage to trees. Currently, lethal control is used to manage grey squirrel populations in Britain, but nonlethal methods might be more acceptable to the public. One such method is contraception with 20,25‐diazacholesterol dihydrochloride (DiazaCon™). DiazaCon™ inhibits the conversion of desmosterol to cholesterol, resulting in increasing desmosterol concentrations and decreasing cholesterol concentrations. Because cholesterol is needed for the synthesis of steroid reproductive hormones, such as progesterone and testosterone, inhibition of cholesterol synthesis indirectly inhibits reproduction. Desmosterol is used as a marker of efficacy in laboratory studies with species that do not reproduce readily in captivity. Grey squirrels were gavaged with a DiazaCon™ solution for 2 days, and then fed DiazaCon™‐coated peanuts for an additional 8 days at target doses of 50 and 100 mg DiazaCon™ per kg body weight. There was a significant difference in cholesterol concentrations in the treatment groups compared to the control group. Cholesterol was reduced by ≥ 40% for 2 months in both treatment groups. There were no differences among groups with respect to blood chemistry and hematology parameters, and mean values are reported. The mean overall dose of DiazaCon™ received was 29.0 ± 1.6 and 55.3 ± 4.3 mg/kg in the low (50 mg/kg) and high dose (100 mg/kg) groups, respectively. DiazaCon™ might provide an effective, acceptable alternative to lethal control.

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Section: Introductionmentioning

confidence: 99%

Feeding of grey squirrels (Sciurus carolinensis) with the contraceptive agent DiazaCon™: effect on cholesterol, hematology, and blood chemistry

Yoder

Mayle

Furcolow

et al. 2011

Integrative Zoology

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show abstract

“…The gray squirrel (Sciurus carolinensis) was introduced into the UK from North America in the 1800s (Gurnell and Pepper, 1993). Red squirrels disappeared from most British deciduous and mixed woodland in the 15-to 20-yr period after arrival of gray squirrels in these areas (Gurnell, 1993). Decline of red squirrels in the British Isles and replacement by gray squirrels continues.…”

Section: Introductionmentioning

confidence: 99%

“…Red squirrel population numbers have fluctuated widely over the last 300 yr, perhaps because of a dependence on tree seed availability (Gurnell and Pepper, 1993). The gray squirrel (Sciurus carolinensis) was introduced into the UK from North America in the 1800s (Gurnell and Pepper, 1993). Red squirrels disappeared from most British deciduous and mixed woodland in the 15-to 20-yr period after arrival of gray squirrels in these areas (Gurnell, 1993).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Red squirrels (Sciurus vulgaris) are part of the wild fauna of the UK, where they fill an important ecologic niche (Gurnell and Pepper, 1991). Red squirrel population numbers have fluctuated widely over the last 300 yr, perhaps because of a dependence on tree seed availability (Gurnell and Pepper, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Bone Assessment of Free-Living Red Squirrels (Sciurus Vulgaris) From the United Kingdom

Garriga

Sainsbury

Goodship

2004

Journal of Wildlife Diseases

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Metabolic bone disease has been reported in free-living red squirrels (Sciurus vulgaris) in the United Kingdom but the prevalence of this disease is unknown. In this study the bone quality of free-living red squirrels in the UK was assessed by radiology and bone densitometry. The study comprised 20 red squirrels found dead and submitted to the Zoological Society of London (UK) between 1997 and 1998, 10 were from the Isle of Wight (IoW), where gray squirrels (Sciurus carolinensis) are absent, and 10 were from Cumbria (Cu), where gray squirrels are present. Gray squirrels are considered potential competitors for red squirrels. Radiologic evaluation of humerus, femur, tibia, radius, and ilium revealed a slightly lower bone density and thinner cortices in red squirrels from the IoW when compared with those from Cu. Dual-energy X-ray absorptiometry was used to measure bone mineral content and density of the isolated right humerus and femur of 19 of the 20 red squirrels. The bone densitometry study reinforced the radiographic findings. The IoW specimens had lower bone mineral density values, although statistical significance (PϽ0.05) between animals from the IoW and Cu was only reached for the proximal epiphysis of the femur and between males from the IoW and males from Cu for the proximal epiphysis of the humerus. A highly positive correlation (rϾ0.94) was found when the bone mineral content and density between the femur and the humerus among groups and within each group were compared, showing a uniform level of mineralization between upper and lower limbs. These findings suggested generalized bone loss for the IoW red squirrels that may be compatible with some degree of osteopenia. Within the wide range of causes that lead to osteopenia, malnutrition (especially protein deficiency), calcium and copper deficiencies, and genetic factors remain as possible etiologies.

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Opportunistic viral surveillance confirms the ongoing disease threat grey squirrels pose to sympatric red squirrel populations in the UK

et al. 2023

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Background: Red Squirrels United was a UK landscape-scale grey squirrel management programme undertaken between 2016 and 2020. Methods: A total of 11034 grey squirrels were removed by culling, with 1506 necropsied and 1405 suitable for adenovirus (AdV) or squirrelpox virus (SQPV) quantitative PCR (qPCR) analysis. Spleen, lip or hair were extracted, and DNA was isolated, with samples tested in duplicate by qPCR. Results: Of 1378 tissue samples, 43% were positive for AdV and 10% for SQPV. Of 1031 hair samples, 11% were positive for AdV and 10% for SQPV. Overall, 762 of 1405 (54%) animals were positive for one or both viruses. Limitations: Ad hoc sampling was undertaken from limited geographical areas but provided the only dataset from that period, instead of extrapolating from historical data. Conclusions: The grey squirrel is an asymptomatic reservoir host for AdV and SQPV. Interspecific infection transmission potential is demonstrated. Grey squirrel management by culling is essential for mainland red squirrel viability until other suitable management tools are available.

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A critical look at conserving the British Red Squirrel Sciurus vulgaris

Cited by 109 publications

References 13 publications

Feeding of grey squirrels (Sciurus carolinensis) with the contraceptive agent DiazaCon™: effect on cholesterol, hematology, and blood chemistry

Feeding of grey squirrels (Sciurus carolinensis) with the contraceptive agent DiazaCon™: effect on cholesterol, hematology, and blood chemistry

Bone Assessment of Free-Living Red Squirrels (Sciurus Vulgaris) From the United Kingdom

Opportunistic viral surveillance confirms the ongoing disease threat grey squirrels pose to sympatric red squirrel populations in the UK

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