Squirrels

The grey squirrel is a common garden mammal that both delights by its acrobatic movements and annoys by damaging trees, feeding on flower buds, bulbs, fruits and vegetables.

Grey squirrel. Image: ©www.gardenworldimages.com

Quick facts

Common name Grey squirrel
Scientific name Sciurus carolinensis
Plants affected Many ornamental plants, fruits and vegetables
Main symptoms Strips bark from trees, eats flower buds, bulbs, corms, seeds, ripening fruits and vegetables
Most active Year round

What are grey squirrels?

Grey squirrels often enter gardens from adjacent woodlands or other areas with trees and shrubs.

They attack a wide range of ornamental plants, fruits and vegetables. Particularly at risk are tulip bulbs, crocus corms, sweetcorn, strawberries, apples, pears, nuts, sunflower seed heads and flower buds of camellias and magnolias. Trees, including sycamore, maples, ash and beech, can be badly damaged or even killed by bark stripping.

Symptoms

You can usually spot the squirrels in your garden. This is some of the damage they cause:

  • Eat fruits, nuts, seeds, flower buds, vegetables and bark
  • Dig up and eat bulbs and corms
  • Raid bird feeders and take eggs from birds’ nests
  • Damage lawns by burying or digging up winter food stores
  • Strip bark off trees, especially sycamore, maples, ash and beech
  • Gnaw on plastic, such as hosepipes and plastic netting

    Grey squirrels eat a wide range of plants and plant parts, including flower buds, like these from Corylus avellana (hazel).

    Control

    Non-chemical control

    It is not possible to stop squirrels from coming into a garden. Netting can give protection to fruits and shrubs when squirrels are showing interest in them. Wire netting is best used for permanent structures such as fruit cages, as squirrels can quite easily bite through plastic.  Netting can also be placed over areas where bulbs and corms have been planted, to deter squirrels from digging them up.
    Various designs of squirrel-proof bird feeders and tables are available from most garden centres. These usually enclose the food dispenser in a stout wire cage that allows birds access while excluding squirrels

    Animal repellent substances and scaring devices are likely to give no more than short-term protection.

    It is permissible to control grey squirrels by shooting or trapping, provided this is done in a humane manner, but shooting is not often feasible in gardens for legal and safety reasons.

    Traps are available from some garden centres or mail order companies. The most widely used is a cage-type trap that will capture squirrels alive. Such traps can be baited with peanuts and must be checked at least once every 24 hours, preferably morning and evening. Under the Wildlife and Countryside Act it is illegal to release non-indigenous animals into the wild, so any grey squirrels caught should be killed. Methods considered to be within animal welfare law include shooting or allowing the squirrel to escape into a sack, where it can be held while a sharp blow is delivered to its head. Drowning squirrels is not a humane method of dispatching squirrels and is illegal.

    Unfortunately, more squirrels are likely to move in to occupy the vacated territory, so a garden is unlikely to be squirrel-free for long.

    Chemical control

    There are no poisons approved for use against grey squirrels in gardens.

    Biology

    The grey squirrel originates from North America and was introduced into Britain during the 19th century. It is now found throughout most of Britain and has largely replaced the native red squirrel (Sciurus vulgaris). The decline of the red squirrel has been mostly caused by habitat changes and endemic diseases, coupled with the fact that the presence of the more competitive grey squirrel hampers population recovery.  With the exception of some areas of Italy, the grey squirrel is not found elsewhere in Europe outside of Britain and Ireland. Both species of squirrel can cause damage in gardens: however if the red squirrel is seen in gardens it should be tolerated due to its rarity.  The red squirrel has the highest level of protection under the Wildlife and Countryside Act.

    Grey squirrels can produce two litters a year, which are raised in nest-like structures called dreys. Young are generally produced in February and July; a typical litter size is three or four. Grey squirrels are active throughout the year on all but the coldest days.

    Most bark stripping appears to be associated with stress brought on by territorial disputes with other squirrels. It is more likely to happen when squirrel numbers are high and there is increased competition for territories.

     

    Image: © GWI/Dave Bevan. Available in high resolution at www.gardenworldimages.com

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