26 October 2018

Pest advice for controlling Grey Squirrels

Have you heard something rustling in your attic or loft and suspect squirrels? As adorable as squirrels might be, they can be an incredibly destructive and distressing pest to have in your home or work. Learn all about grey squirrels in our ultimate pest control guide.

Pest controllers get thousands of call-outs for squirrels every year, and this is in part due to the damage they cause to your home and the noises squirrels make at night – which can be very distressing.

Whether you’re thinking about doing some DIY squirrel pest control, or you’re looking to get yourself a professional pest controller to come out to you, this guide is for you.

Pest advice for controling squirrels

Our figures suggest people have more problems with squirrels during the spring and autumn when they’re looking for food.

Grey squirrels Sciurus carolinensis are invasive pests, not native to the UK. As their numbers have increased in the UK, so to has the damage they cause. Grey squirrels are also responsible for the decline in native red squirrel Sciurus vulgaris numbers.

As well as causing physical damage and noise complaints, like other rodents, squirrels can cause contaminations.

In this guide:

The dangers: why we control grey squirrels

Even though the grey squirrel is widely appreciated for its grace and ‘cuteness’ by much of the UK – the pest management industry knows that there are times when the lethal control of grey squirrels is necessary.

There are three reasons we control grey squirrels:

  • Their potential to damage to your home, business and health
  • The destruction of UK forests
  • The impact on our native wildlife, in particular the red squirrel.

Male and female squirrels

Squirrel damage in your home, business and to your health 

Grey squirrels can cause damage when they enter roof spaces of houses and buildings. For example, they can:

  • Chew on woodwork and ceilings
  • Strip insulation from electrical wires
  • Tear up fibreglass insulation 
  • Contaminate cold water tanks with urine and droppings.

People also report sleep issues due to the loud noises they make at night while they’re scuttling around your attic. Squirrels are most active before sunrise, especially in winter, but ends well before sunset. Their peak activity is activity is four-five hours before daybreak.

Grey squirrels often associate humans with food, meaning they sometime approach people. Some people fear being attacked, however it’s very rare for a squirrel to actually attack!

In gardens and allotments, they can take fruit, raid nests of small birds and dig holes in lawns to bury food.

Signs of squirrels in your home or business

These are the seven signs easiest signs to spot when looking for evidence of squirrels in your home or loft.

  1. Scratching and rustling sound from your loft or a wall cavity
  2. Spotting droppings in the loft – although you might need a pest controller to identify these droppings
  3. Smell of urine in the loft area might indicate the infestation has been going on some time
  4. Spotting lots of other squirrels around your property, particularly near your roof or on high fences
  5. Fruit and nuts being stolen from bird feeders, or the feeders being disturbed/knocked over
  6. Bark being stripped from trees in your garden
  7. Holes in vents or damage to your insulation foam.

If you’ve noticed a few of these signs, then it might be time to find a pest control company.

Grey squirrels and our forests

Grey squirrels cause damage to trees such as beech, oak and chestnut. They strip bark at the base of trees which causes them to weaken and eventually to die.

Grey squirrels also:

  • Raid birds’ nests to prey on eggs and fledglings
  • Damage orchards and gardens
  • Reap havoc on historic and ancient woodlands.

Squirrels cause 6-10 million damage to British forestry every year

The European Squirrel Initiative (ESI) point out that around 12% of England is covered by trees and this is set to rise.

Woods and forests provide for carbon sequestration and help fight global warming. Timber also has an economic value and commercial forestry plays an important part in our rural economy.

The UK Forestry Commission estimates grey squirrels causes £6-10 million damage to British forestry per year.  

ESI are concerned unless something is done, there will be no oak, beech, or sweet chestnut mature trees for the next generation.

The native red squirrel vs invasive grey squirrels

Squirrels can be right or left handed

The grey squirrel was deliberately introduced to England, Wales, Scotland and Northern Ireland from North America in the Victorian era. Since then, it’ colonised 90% of England and Wales and is becoming a problem in Scotland.

The Wildlife Trusts estimates there are only around 140,000 native red squirrels left in the UK, compared to 2.5 million grey squirrels.

Squirrel distribution maps 1945-2000-2010

There’s been many scientific studies that have show that the major contributing factor for the decline of the red squirrel is the introduction of its grey cousin. As well as the competition for shelter and food, grey squirrels can transmit the squirrelpox virus to red squirrels.

Once a red squirrel has squirrelpox, it’ll usually die of dehydration within 2 weeks. The grey squirrel can carry the disease, but their health is unaffected.

The grey squirrel, here in Britain and Europe, is classed as an Invasive Alien Species (IAS) and as such is recognised as being in the top worst 100 such species in the world. An IAS is any animal that is not native to the UK.

Because grey squirrels are an invasive pest species, it is against the law to re-release a grey squirrel if it’s been caught alive, per the Wildlife and Countryside Act 1981. That means a professional pest controller is legally obliged to dispatch any grey squirrel they catch alive.

Red squirrels are extremely susceptible to Squirrelpox virus, which is lethal

Although we can all appreciate the joy that squirrels bring the UK fauna enthusiasts. Red squirrels are not only protected, but are much sought out because catching sight of them is so rare. Unless you’re around Scotland, Northern Ireland or the Isle of Wight, there’s a good chance you’ve never seen a red squirrel.

Grey squirrel biology, behaviour and habitat

Grey squirrel lifespan weight body length tail length


The drey (nest) may be in a hole in a tree or set against the trunk and branches. Alternatively they can make themselves quite at home in an attic or roof space.


Pregnancy (gestation) lasts 44 days, and their young are called kittens. They usually have two litters a year, each with three to seven kittens.


Kittens are born with closed eyes, no teeth and no hair. After about seven weeks they look like small versions of their parents and are ready to leave the drey.


Squirrels moult their coat twice a year – once after winter and then in the late summer before the weather gets colder again.

Squirrels can hang upside down and are good swimmers

Preventing squirrels getting into your property or damaging your trees

Prevention is always better than cure.

Habitat management like as cutting back trees or branches that are overhanging a building, or trimming dense ivy can help prevent squirrels gaining access to a roof in the first place.

Next consider proofing entry points to your roof. For example, block the gaps and entrances holes with tightly wedged mesh or metal plates, wherever possible. A pest controller should be able to help you with this.

For tree protection, close fitting metal sleeves can protect them from the strong rodent incisors. This should be at least 0.75m deep, and the bottom edge should be at least 1.5m from the ground.

The metal should be a smooth surface to assist in preventing the squirrel from gaining a toehold.

DIY squirrel pest control

Although you can potentially do a lot of the proofing work to stop squirrels entering your property, DIY squirrel control is unlikely to be affective – and could potentially be very dangerous.

Traps are available online, however not every rodent trap is authorised to control squirrels. Any squirrel you caught alive would have to be killed, as per the Wildlife and Countryside Act 1981.

Traps should never be used without adequate training.

Any squirrel that you kill would have to be done humanely and this can be very distressing.

There are no amateur use products for poisoning squirrels available to the public. Professional pest controllers do have access to legally authorised grey squirrel poisons (Warfarin only) that are only for use inside buildings

Things you can do:

  • Trim tree branches that overhang your roof
  • Rove anything stacked up against the side of your building
  • Seal all entry points (proofing).

Finding a pest controller to get rid of squirrels.

It’s important with squirrels (as with all pest species) that a pest controller assesses whether lethal control is necessary.

In the first instance, proofing such as the guidance in the previous section should be put into place. If this is unsuccessful calling a professional should be your next action.

Squirrels in the UK are invasive species

To control squirrels, professionals might use:

  • Spring traps
  • Live capture traps
  • Drey poking.

Your pest controller should be qualified and working for a professional pest management company. BPCA has a list of qualified and audited member companies that can be found through our Find a pest controller tool.

Search for your local BPCA member

Source: A-Z

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