How Tiny Garden Tunnels Are Giving London's Hedgehogs a Fighting Chance

London's Underground Network for Hedgehogs

Beneath the fences and walls of Barnes in south-west London, a quiet revolution is taking place. A growing community initiative known as the "hedgehog highway" is creating a web of small openings and passages that allow one of Britain's most endangered mammals to move freely through urban gardens and green spaces.

The concept is simple but effective: small holes are cut or drilled through garden fences, walls, and other barriers, giving hedgehogs the freedom to roam between properties. In some cases, passages have even been bored through thick Victorian boundary walls to ensure the animals are not cut off from the habitats they need to survive.

One Resident's Passion Sparked a Community Movement

The hedgehog highway in Barnes reportedly began when local resident Michel Birkenwald discovered a hedgehog living in his garden and decided to take action. What started as a personal campaign quickly gained momentum, spreading across the wider community and inspiring neighbours to adapt their own outdoor spaces.

Among those leading the charge is Alice Mallorie, who has spent years transforming her Barnes garden into a hedgehog-friendly haven. In addition to creating access points, she has installed dedicated feeding stations to support the nocturnal animals during their nighttime forays.

"I guess in a very low-key way, being able to see any wildlife in your garden is good for the soul," Mallorie told BBC London. "They're going down in numbers, so there's something about them which is vulnerable and charming."

A Species Under Serious Threat

The urgency behind these local efforts is underscored by alarming national data. According to a 2022 report, Britain has lost up to three-quarters of its rural hedgehog population since the year 2000. The species is now officially classified as vulnerable to extinction on the red list for British mammals.

Urban populations have not been spared either. The Zoological Society of London (ZSL) has been conducting extensive monitoring across 21 London boroughs using camera traps, collecting millions of images to track where hedgehogs are still active. Their research identifies Barnes as a key hotspot for the species — a status that makes community conservation efforts there all the more significant.

Why Urban Environments Are So Dangerous for Hedgehogs

Kate Scott-Gatty, a researcher at ZSL's Institute of Zoology, explains that hedgehogs are particularly ill-equipped to navigate modern urban landscapes.

"Hedgehogs are quite small, they've got short legs — they're not like squirrels and foxes that can get almost anywhere across London," she said. "They're really susceptible to barriers and urban infrastructure — roads, fences, walls — and that means they can't get to the places they need to."

Unlike more adaptable urban wildlife, hedgehogs rely on connected green corridors to find food, mates, and shelter. When those corridors are blocked, populations become isolated and eventually collapse.

Small Holes, Big Impact

The hedgehog highway model demonstrates how modest, low-cost interventions at the community level can deliver meaningful conservation outcomes. By simply making a 13cm-square hole at the base of a garden fence, homeowners can connect their space to a wider network — effectively turning a patchwork of private gardens into a functioning wildlife habitat.

As urban sprawl continues to fragment natural environments, grassroots initiatives like the one in Barnes offer a compelling blueprint for how cities and their residents can become active participants in protecting vulnerable species — one small hole at a time.