Annotated Bibliography on the Ecology and Management of Invasive Species: Eastern Grey Squirrel (Sciurus carolinensis)

The website is maintained by a research unit based at the University of Liverpool that aims to provide information on the ecology and management of invasive species in the United Kingdom. The site provides species descriptions, life history details, range information as well as discussing the impacts and potential control measures of eastern grey squirrels. Eastern grey squirrels were introduced to Britain in the late 19th century and now cause major damage to ecosystems. They gnaw the bark of trees which kills or slows the growth of the trees. Squirrels remove the bark 30 cm above the ground. Grey squirrels also impact European red squirrels through competition and by possibly acting as a vector for the disease parapoxvirus. Grey squirrels are found primarily in deciduous woodlands but also occurs in coniferous and mixed stands. Although the red squirrel is a different species from the native red squirrel in British Columbia, the potential impacts may be similar although this requires further research. The best control options for grey squirrels include the use of Warfarin (rodenticide) in specialized hoppers (used only where there are no red squirrels) and cage trapping in conjunction with shooting. These techniques may also be useful Garry oak ecosystems. However, new individuals from adjacent populations will rapidly repopulate an area and total eradication is unlikely. Baits can be used to lure squirrels away from sensitive sites. Immuno-contraception methods require more research before they can be implemented.