“A single wedding gift in 1911 – 12 grey squirrels – now endangers 90% of Britain’s native red squirrels.”
Grey squirrels (Sciurus carolinensis), brought to the UK from North America in the 19th century, rank among Britain’s most damaging invasive species. With 2.7 million greys outnumbering a mere 140,000 red squirrels (Sciurus vulgaris), we must act swiftly to safeguard ecosystems, timber resources, and biodiversity.
Learn how grey squirrel control affects local ecosystems with our environmental impact guide, highlighting responsible methods and sustainable pest management practices.
Damage to Woodlands
Bark stripping: Greys peel bark from sycamore, beech, and oak trees, costing the UK timber industry £37 million yearly.
Carbon impact: Affected oaks store 48% less CO₂, aggravating climate change.
Threats to Wildlife
Red squirrel extinction: Greys spread squirrelpox virus (SQPV), lethal to reds.
Bird declines: Songbird fledglings drop by 15% in grey-heavy woodlands.
“Grey squirrels don’t merely harm trees – they dismantle entire ecosystems.” – Forestry Commission ecologist.
Step-by-Step Ethical Trapping
Deploy cage traps with walnuts or hazelnuts as bait.
Inspect traps twice daily (a legal must).
Use an airgun for dispatch (RSPCA-endorsed).
Case Study – Anglesey, Wales:
10,000 greys culled since 1998.
Red squirrel numbers climbed to 700.
Positive Outcomes
Carbon recovery: Healthy oaks soak up 48% more CO₂.
Biodiversity boost: Fungal diversity rises 22% in managed zones.
Hidden Risks
Over-culling could starve predators like goshawks.
Relocation risks spreading SQPV to new areas (banned under Wildlife Act 1981).
5-Step Garden Protection Plan
Bird feeders: Fit metal cages with safflower seeds (greys detest them).
Tree guards: Add spiral protectors to young tree bark.
Report sightings: Log them on the CEDaR Online Tool at
(https://www2.habitas.org.uk/records/ISI)
Volunteer: Join Red Squirrel Groups (85% patrol locally).
Avoid feeding greys: Even unintentional scraps fuel their spread.
Myth Buster:
“Greys are just tougher survivors” → They snatch unripe nuts reds can’t stomach.
Emerging Technologies
Gene drives: Target grey fertility genes (trials slated for 2030).
AI monitoring: Camera traps text landowners alerts (piloted in Devon).
Government Targets:
Cut greys by 50% near red strongholds by 2030.
£2M in grants for organic repellents.
Why can’t red squirrels fight back against grey squirrels?
Red squirrels struggle to compete with grey squirrels for several reasons:
Size: Grey squirrels are bigger and need more food.
Food choices: Grey squirrels can eat more types of food, even unripe nuts that red squirrels can’t digest.
Living spaces: Grey squirrels do well in different forest types, while red squirrels prefer specific habitats.
Squirrel Pox: Grey squirrels carry a virus that doesn’t hurt them but can kill red squirrels.
Early eating: Grey squirrels often eat food before it’s ready for red squirrels.
Numbers game: There are usually more grey squirrels in an area than red squirrels.
Food theft: Grey squirrels sometimes take food that red squirrels save for winter.
These factors make it hard for red squirrels to survive and grow their populations in areas where grey squirrels live.
Is killing grey squirrels legal?
Yes, in the UK, it’s legal to kill grey squirrels, but there are rules to follow. Grey Squirrels are considered invasive pests that harm native wildlife and damage trees.
Key points about grey squirrel control:
Humane methods must be used to avoid suffering.
It’s illegal to release grey squirrels into the wild or keep them as pets.
If you trap a grey squirrel, you’re required by law to kill it humanely.
Cruel methods like drowning are forbidden.
Non-lethal options include:
Using squirrel-proof bird feeders
Sealing entry points to buildings
Planting squirrel-resistant plants
Important: Red squirrels are a protected species and must not be harmed. If unsure, consult a wildlife expert for guidance on proper squirrel management.
Do pine martens really control grey squirrels?
Yes, pine martens help control grey squirrel populations. Research shows that areas with pine martens have about 70% fewer grey squirrels. Pine martens are good at catching grey squirrels because:
Grey squirrels don’t recognise pine martens as a threat
Pine martens can climb trees and hunt grey squirrels easily
Red squirrels are better at escaping to thin branches where pine martens can’t go
This natural control helps red squirrels by:
Reducing competition for food
Lowering the spread of squirrelpox, a disease that harms red squirrels
Scientists see this as a good thing for the ecosystem. It helps protect native red squirrels and reduces damage caused by invasive grey squirrels to forests and gardens.
How do I protect my roof?
To safeguard your roof:
Install wire mesh over eaves to deter pests
Trim overhanging branches, keeping them 10 feet away
Regularly inspect for damage, especially after storms
Clean gutters and remove debris seasonally
Promptly repair any cracks, holes, or loose shingles
Ensure proper attic ventilation to prevent moisture buildup
Apply pest repellents around your home’s perimeter
These proactive measures will help maintain your roof’s integrity and extend its lifespan.
Can greys and reds coexist?
Grey squirrels (Sciurus carolinensis) and red squirrels (Sciurus vulgaris) rarely coexist long-term in the same habitat. Greys typically outcompete reds for food resources and carry the squirrelpox virus, which is fatal to reds.
Limited coexistence may occur if:
Grey population density remains below 5 per square kilometre
The ecosystem provides distinct niches for each species
Food sources are abundant for both populations
However, without active conservation efforts, grey squirrels usually displace red squirrels over time in shared environments.
Control greys to save reds and woodlands, but tread carefully to avoid ecological jolts.
Back ethical control: Donate to Red Squirrel United.
Spread the word (#SaveRedsUK).
“Saving red squirrels isn’t just about one species – it’s about mending Britain’s forests.”