Sciurus carolinensis
System : Terrestrial
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Animalia
Chordata
Mammalia
Rodentia
Sciuridae
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Common name
scoiattolo grigio (Italian), Grauhoernchen (German), grey squirrel (English), gray squirrel (English)
Synonym
Similar species
Summary
The grey squirrel (Sciurus carolinensis) is native to deciduous forests in the USA and has been introduced to the UK, Ireland, Italy and South Africa. In the introduced range grey squirrels damage trees by eating the bark and in Europe they cause the local extinction of red squirrel (Sciurus vulgaris) populations through competition and disease.
Species Description
The grey squirrel (Sciurus carolinensis) is a medium-sized tree squirrel with no sexual dimorphism in size or colouration. Ranges of external measurements (in mm) are: total length, 380-525; length of tail, 150-250; length of hind foot, 54-76; length of ear, 25-33. Adult body mass ranges from 300 to 710g. The back is grizzled dark to pale grey and may be washed with cinnamon on hips, feet, and head. Ears are buff to grey to white in the north; tail is white to pale grey. Underparts are white to grey to buff to cinnamon. In the native range of the species in North America melanism is common in the north and albinism is rare (Koprowski, 1994).
Notes
Grey squirrels (Sciurus carolinensis) cache food in small pits to see them through the winter. They have excellent spatial memory allowing these caches to be relocated.
Uses
Grey squirrels (Sciurus carolinensis) are harvested for food in Mississippi (USA). Squirrels are popular animals to watch throughout their native and introduced ranges.
Habitat Description
Grey squirrels (Sciurus carolinensis) survive best in mature deciduous woodland where there is a mixture of nut producing species that produce food that can be stored overwinter. In the UK they are common visitors to urban gardens where they frequently eat food left out for birds.
Reproduction
Placental, sexual. 2-3 young per litter, 1-2 litters per year.
Nutrition
Grey squirrels (Sciurus carolinensis) eat nuts, buds, flowers, seeds, fruits, fungi, some insects and occasionally bird eggs. During low food periods, they strip bark to get to inner bast and cambian layers. They also feed on maize if grown close to woodlands.
Pathway

Principal source:

Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG)

Review:

Publication date: 2005-10-17

Recommended citation: Global Invasive Species Database (2024) Species profile: Sciurus carolinensis. Downloaded from http://iucngisd.org/gisd/species.php?sc=65 on 21-11-2024.

General Impacts
In overlap areas, the grey squirrel (Sciurus carolinensis) causes the extinction of the red squirrel (see Sciurus vulgaris in IUCN Red List of Threatened Species) through competitive exclusion. It can also cause damages to woodland through bark stripping activity, sycamore (Acer pseudoplantanus) and beech (Fagus sylvatica) are particularly badly affected (Bertolino and Genovesi, 2003). Grey squirrels also act as a reservoir for a poxvirus that red squirrels are affected by. This has been postulated as another reason why red squirrels go extinct in the presence of grey squirrels; a phenomonon known as pathogen-mediated competition (Gurnell et al. 2006). Squirrels can be a garden pest by digging up bulbs and eating the bark of ornamental plants.
Management Info
The Forestry Commission, in the United Kingdom, have a research programme that includes investigating the impact of grey squirrels on woodland biodiversity & identifying efficient control strategies, developing cost effective methods of managing impacts on timber production, developing a decision-support system for woodland managers on targeting grey squirrel control to support sustainable forest management, and promoting and supporting best practice management for the control of grey squirrels and their impacts. Please follow this link for an annual summary of their research

Physical: Physical management of grey squirrels includes bounty payments, free cartridges (for shooting), tail bonuses, and trapping.

Chemical: Warfarin (anti-coagulant) is the only cost-effective method of control currently available.

Countries (or multi-country features) with distribution records for Sciurus carolinensis
ALIEN RANGE
NATIVE RANGE
  • canada
  • united states
Informations on Sciurus carolinensis has been recorded for the following locations. Click on the name for additional informations.
Lorem Ipsum
Location Status Invasiveness Occurrence Source
Details of Sciurus carolinensis in information
Status
Invasiveness
Arrival date
Occurrence
Source
Introduction
Species notes for this location
Location note
Management notes for this location
Impact
Mechanism:
Outcome:
Ecosystem services:
Impact information
In overlap areas, the grey squirrel (Sciurus carolinensis) causes the extinction of the red squirrel (see Sciurus vulgaris in IUCN Red List of Threatened Species) through competitive exclusion. It can also cause damages to woodland through bark stripping activity, sycamore (Acer pseudoplantanus) and beech (Fagus sylvatica) are particularly badly affected (Bertolino and Genovesi, 2003). Grey squirrels also act as a reservoir for a poxvirus that red squirrels are affected by. This has been postulated as another reason why red squirrels go extinct in the presence of grey squirrels; a phenomonon known as pathogen-mediated competition (Gurnell et al. 2006). Squirrels can be a garden pest by digging up bulbs and eating the bark of ornamental plants.
Red List assessed species 3: EN = 1; LC = 2;
View more species View less species
Locations
ITALY
UNITED KINGDOM
Mechanism
[2] Competition
[2] Predation
[2] Disease transmission
[1] Grazing/Herbivory/Browsing
Outcomes
[2] Environmental Ecosystem - Habitat
  • [1] Reduction in native biodiversity
  • [1] Modification of successional patterns
[4] Environmental Species - Population
  • [2] Population size decline
  • [2] Plant/animal health
[2] Socio-Economic
  • [1] Damage to agriculture
  • [1] Damage to infrastructures
Management information
The Forestry Commission, in the United Kingdom, have a research programme that includes investigating the impact of grey squirrels on woodland biodiversity & identifying efficient control strategies, developing cost effective methods of managing impacts on timber production, developing a decision-support system for woodland managers on targeting grey squirrel control to support sustainable forest management, and promoting and supporting best practice management for the control of grey squirrels and their impacts. Please follow this link for an annual summary of their research

Physical: Physical management of grey squirrels includes bounty payments, free cartridges (for shooting), tail bonuses, and trapping.

Chemical: Warfarin (anti-coagulant) is the only cost-effective method of control currently available.

Locations
CANADA
IRELAND
ITALY
PITCAIRN
UNITED KINGDOM
Management Category
Prevention
Control
Monitoring
Bibliography
11 references found for Sciurus carolinensis

Management information
Bomford, M., 2003. Risk Assessment for the Import and Keeping of Exotic Vertebrates in Australia. Bureau of Rural Sciences, Canberra.
Summary: Available from: http://www.feral.org.au/wp-content/uploads/2010/03/PC12803.pdf [Accessed August 19 2010]
Forestry Commission, Great Britian., 2008. Management of grey sqirrels.
Summary: Available from: http://www.forestresearch.gov.uk/forestry/kirn-5m5emv [Accessed 20 february 2008]
Genovesi, P. and Bertolino, S., 2001. Human dimension aspects in invasive alien species issues: the case of the failure of the grey squirrel eradication project in Italy. In: McNeely, J.A. (Ed.), The Great Reshuffling: Human Dimensions of Invasive Alien Species. IUCN, Gland Switzerland and Cambridge, UK, pp. 113�119.
Genovesi, Piero (in press). Threats posed by the Grey squirrel in Europe and a strategy for the future: the Italian perspective. From a presentation at the 6th Meeting of the Group of Experts on Invasive Alien Species (Palma de Majorca, 9-11 June 2005) to be published by the Council of Europe.
Koprowski, J.L. 1994. Sciurius carolinensis. Mammalian Species 480: 1-9.
Summary: In depth information about the species covereing anatomy, breeding, ecology etc
Mayle, Brenda and Smith, Linda (in press). Non-Native Invasive Species - the Grey Squirrel Sciurus carolinensis. A particular example of the threat posed to European Biodiversity. From a presentation at the 6th Meeting of the Group of Experts on Invasive Alien Species (Palma de Majorca, 9-11 June 2005) to be published by the Council of Europe.
Murray, C. and C. Pinkham. 2002. Towards a Decision Support Tool to Address Invasive Species in Garry Oak & Associated Ecosystems in BC. Prepared by ESSA Technologies Ltd., Victoria, B.C. for the GOERT Invasive Species Steering Committee, Victoria, 96 pp.
Summary: Available from: http://www.goert.ca/documents/GOEDSTreport.pdf [Accessed 13 February 2008]
The Garry Oak Ecosystems Recovery Team (GOERT)., 2003. Annotated Bibliographies on the Ecology and Management of Sciurus carolinensis
The Garry Oak Ecosystems Recovery Team (GOERT)., 2003. Field manual of Sciurus carolinensis
Summary: Available from: http://www.goert.ca/documents/InvFS_sciucaro.pdf [Accessed 13 February 2008]
General information
CONABIO. 2008. Sistema de informaci�n sobre especies invasoras en M�xico. Especies invasoras - Mam�feros. Comisi�n Nacional para el Conocimiento y Uso de la Biodiversidad. Fecha de acceso.
Summary: English:
The species list sheet for the Mexican information system on invasive species currently provides information related to Scientific names, family, group and common names, as well as habitat, status of invasion in Mexico, pathways of introduction and links to other specialised websites. Some of the higher risk species already have a direct link to the alert page. It is important to notice that these lists are constantly being updated, please refer to the main page (http://www.conabio.gob.mx/invasoras/index.php/Portada), under the section Novedades for information on updates.
Invasive species - mammals is available from: http://www.conabio.gob.mx/invasoras/index.php/Especies_invasoras_-_Mam%C3%ADferos [Accessed 30 July 2008]
Spanish:
La lista de especies del Sistema de informaci�n sobre especies invasoras de m�xico cuenta actualmente con informaci�n aceca de nombre cient�fico, familia, grupo y nombre com�n, as� como h�bitat, estado de la invasi�n en M�xico, rutas de introducci�n y ligas a otros sitios especializados. Algunas de las especies de mayor riesgo ya tienen una liga directa a la p�gina de alertas. Es importante resaltar que estas listas se encuentran en constante proceso de actualizaci�n, por favor consulte la portada (http://www.conabio.gob.mx/invasoras/index.php/Portada), en la secci�n novedades, para conocer los cambios.
Especies invasoras - Mam�feros is available from: http://www.conabio.gob.mx/invasoras/index.php/Especies_invasoras_-_Mam%C3%ADferos [Accessed 30 July 2008]
ITIS (Integrated Taxonomic Information System), 2005. Online Database Sciurus carolinensis
Summary: An online database that provides taxonomic information, common names, synonyms and geographical jurisdiction of a species. In addition links are provided to retrieve biological records and collection information from the Global Biodiversity Information Facility (GBIF) Data Portal and bioscience articles from BioOne journals.
Available from: http://www.cbif.gc.ca/pls/itisca/taxastep?king=every&p_action=containing&taxa=Sciurus+carolinensis&p_format=&p_ifx=plglt&p_lang= [Accessed March 2005]
Contact
The following 3 contacts offer information an advice on Sciurus carolinensis
Genovesi,
Piero
Sciurus carolinensis
Organization:
Instituto Nazionale per la Fauna Selvatica
Address:
via Ca Fornacetta 9, Ozzano Emilia (BO) 40064, Italy
Phone:
+39 51 6512228
Fax:
+39 051 7966028
Gurnell,
John
Professor of Ecology, Sciurus carolinensis
Organization:
University of London
Address:
School of Biological Sciences, Queen Mary, University of London, London E1 4NS, UK
Phone:
+44 20 78823041
Fax:
+44 20 89830973
Mayle MSc,
Brenda
Forest Research is Britain s principal organisation for forestry and tree related research. The Ecology Division carries out research to improve management of both grey and red squirrels in forests/woodlands and provides an advisory service on this. Websites: www.forestresearch.gov.uk/greysquirrels and www.forestresearch.gov.uk/fr/INFD-6A4LVQ
Organization:
Squirrel Population Management and Deer Population Ecology. Forest Research, Ecology Division
Address:
Alice Holt Lodge, Wrecclesham, Farnham, Surrey, GU10 4LH. United Kingdom
Phone:
+44 1420 526236
Fax:
+44 1420 520180
Sciurus carolinensis
scoiattolo grigio, Grauhoernchen, grey squirrel, gray squirrel
Date assessed
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Justification for EICAT assessment
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Mechanism(s) of maximum impact
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Description of impacts
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Recommended citation
(2024). Sciurus carolinensis. IUCN Environmental Impact Classification for Alien Taxa (EICAT).