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The IUCN Red List of Threatened Species™ ISSN 2307-8235 (online) IUCN 2008: T42462A22245728 Sciurus carolinensis, Eastern Gray Squirrel Assessment by: Cassola, F. View on www.iucnredlist.org Citation: Cassola, F. 2016. Sciurus carolinensis. The IUCN Red List of Threatened Species 2016: e.T42462A22245728. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en Copyright: © 2016 International Union for Conservation of Nature and Natural Resources Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale, reposting or other commercial purposes is prohibited without prior written permission from the copyright holder. For further details see Terms of Use. The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN Red List Partners are: Arizona State University; BirdLife International; Botanic Gardens Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; and Zoological Society of London. If you see any errors or have any questions or suggestions on what is shown in this document, please provide us with feedback so that we can correct or extend the information provided. THE IUCN RED LIST OF THREATENED SPECIES™ Taxonomy Kingdom Phylum Class Order Family Animalia Chordata Mammalia Rodentia Sciuridae Taxon Name: Sciurus carolinensis Gmelin, 1788 Common Name(s): • English: Eastern Gray Squirrel, Gray Squirrel, Grey Squirrel Assessment Information Red List Category & Criteria: Least Concern ver 3.1 Year Published: 2016 Date Assessed: February 2, 2016 Justification: Listed as Least Concern because of its wide distribution, large population, occurrence in a number of protected areas, and lack of major threats; it is tolerant to habitat disturbance and its population is increasing. Previously Published Red List Assessments 2008 – Least Concern (LC) – http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T42462A10699433.en 1996 – Lower Risk/least concern (LR/lc) Geographic Range Range Description: This species is found in the eastern United States and adjacent southern Canada; southern Quebec to Manitoba, south to eastern Texas and Florida. Its range has been extended through introductions into Quebec, Ontario, New Brunswick, Manitoba, Saskatchewan, British Columbia, Nova Scotia, California, Oregon, Washington, and Montana (Teaford 1986, Koprowski 1994). It is also introduced in the British Isles, Italy, South Africa, and Australia (extirpated by 1973), but these introduced ranges are not included in the map here (Koprowski 1994). Country Occurrence: Native: Canada; United States Introduced: Italy; South Africa; United Kingdom © The IUCN Red List of Threatened Species: Sciurus carolinensis – published in 2016. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en 1 Distribution Map Sciurus carolinensis © The IUCN Red List of Threatened Species: Sciurus carolinensis – published in 2016. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en 2 Population This species is widespread and abundant.There are reported densities of 21/ha in urban parks. Population and range are increasing (J Koprowski pers. comm.). Current Population Trend: Increasing Habitat and Ecology (see Appendix for additional information) It is found in large blocks of hardwood or mixed forests, as well as in urban and suburban areas. Prefers mature deciduous and mixed forests with abundant supplies of mast (e.g., acorns, hickory nuts). A diversity of nut trees is needed to support high densities. It also uses city parks and floodplains. Seldom far from permanent open water. In southern Alabama, narrow bands of hardwoods along ephemeral streams were an important component of the habitat in even-aged pine and mixed pine-hardwood stands. It rests in tree cavity or leaf nest; leaf nests apparently are made primarily by dispersing juveniles 18-19 weeks old. It nests in tree cavities or in leaf nests, usually 25 feet or more above the ground. Most winter-spring litters are born in tree cavities, most spring-summer litters in leaf nests (Teaford 1986). Cavities suitable for nesting are dry, 15-25 cm in diameter, 40-50 cm deep, with an entrance hole about eight cm in diameter (Teaford 1986). Females may move young from tree cavity nest to leaf nest, possibly to escape fleas. In Illinois, most breeding occurs in December-February and May-June; slightly later in more northern latitudes (Koprowski 1994). One or two litters per year. First litter is produced mostly in February-March, sometimes as early as January in some areas; second litter, July or August. Gestation lasts 44 days. Litter size most often is 2-3. Young are tended by female. Weaning is completed at about 10-12 weeks (in spring and/or late summer-early autumn). Most breed as yearlings, sometimes sooner (as early as five months) or later. Reproductive output, including the percentage of adults that produce young and the number of litters per year, is positively correlated with mast abundance. Maximum reproductive longevity is about a decade. Home range averages 0.5-10 ha, with older males tending to have the largest ranges (Teaford 1986); usually home range is less than five hectares (Koprowski 1994). Not territorial, home range overlap is extensive; social system is characterized by a linear dominance hierarchy. Disperses up to a few kilometres from natal area upon approaching sexual maturity. Large-scale one-way emigrations have been observed, generally coinciding with high population density and mast crop failure. It is pray of many predators, but predation does not appear to limit populations (Teaford 1986). Mean annual mortality reported for adults is 42-57% (Koprowski 1994). Diet consists of seeds, fruits, nuts, fungi, occasional insects and small vertebrates (e.g., bird eggs). Scatterhoarder; buries nuts and acorn in autumn for later consumption (winter-spring). It is active during the day, particularly in the morning and late afternoon, though unimodal activity may occur in winter. May be inactive for a day or two during extremely cold, snowy weather. Systems: Terrestrial Threats There are no major threats to this species. © The IUCN Red List of Threatened Species: Sciurus carolinensis – published in 2016. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en 3 Conservation Actions (see Appendix for additional information) The species occurs in a number of protected areas throughout its range. Credits Assessor(s): Cassola, F. Reviewer(s): Amori, G. Contributor(s): Koprowski, J., Linzey, A. & Hammerson, G.A. © The IUCN Red List of Threatened Species: Sciurus carolinensis – published in 2016. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en 4 Bibliography IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-2. Available at: www.iucnredlist.org. (Accessed: 04 September 2016). Koprowski, J.L. 1994. Sciurus carolinensis. Mammalian Species 480: 1-9. Pacifici, M., Santini, L., Di Marco, M., Baisero, D., Francucci, L., Grottolo Marasini, G., Visconti, P. and Rondinini, C. 2013. Generation length for mammals. Nature Conservation 5: 87–94. Teaford, J.W. 1986. Eastern gray squirrel (Sciurus carolinensis). Section 4.7.1, US Army Corps of Engineers Wildlife Resources Management Manual. Technical Report. Wilson, D.E. and Ruff, S. 1999. The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington, DC, USA. Citation Cassola, F. 2016. Sciurus carolinensis. The IUCN Red List of Threatened Species 2016: e.T42462A22245728. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en Disclaimer To make use of this information, please check the Terms of Use. External Resources For Images and External Links to Additional Information, please see the Red List website. © The IUCN Red List of Threatened Species: Sciurus carolinensis – published in 2016. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en 5 Appendix Habitats (http://www.iucnredlist.org/technical-documents/classification-schemes) Habitat Season Suitability Major Importance? 1. Forest -> 1.4. Forest - Temperate - Suitable - 14. Artificial/Terrestrial -> 14.3. Artificial/Terrestrial - Plantations - Suitable - 14. Artificial/Terrestrial -> 14.4. Artificial/Terrestrial - Rural Gardens - Suitable - Conservation Actions in Place (http://www.iucnredlist.org/technical-documents/classification-schemes) Conservation Actions in Place In-Place Land/Water Protection and Management Conservation sites identified: Yes, over entire range Occur in at least one PA: Yes Additional Data Fields Distribution Estimated extent of occurrence (EOO) (km²): 7077743 Population Population severely fragmented: No Habitats and Ecology Generation Length (years): 7-8 © The IUCN Red List of Threatened Species: Sciurus carolinensis – published in 2016. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T42462A22245728.en 6 The IUCN Red List Partnership The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN Red List Partners are: Arizona State University; BirdLife International; Botanic Gardens Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; and Zoological Society of London. THE IUCN RED LIST OF THREATENED SPECIES™