Why a tiny gap is a lifeline for hedgehogs

Hedgehogs are in trouble. The UK population has fallen dramatically in recent decades, and one of the biggest reasons is that our gardens have become fragmented. A hedgehog can travel up to two kilometres in a single night, searching for food, mates and shelter. But a solid fence or wall stops them in their tracks. They then have to risk crossing roads, which is fatal for thousands every year. By making a small gap – just 13 centimetres square – you can reconnect your garden to your neighbour's, creating a safe route that keeps hedgehogs off the tarmac.

The magic measurement: 13 centimetres

You might think a hedgehog is too spiky and round to squeeze through a small hole. In fact, an adult hedgehog can comfortably pass through a gap 13cm by 13cm – roughly the size of a CD case. That's small enough to keep pets in, but perfect for a hedgehog on the move. A 13cm gap is also too small for most dogs and cats to get through, though a determined terrier might try. If you have larger pets, consider a purpose-built tunnel that runs under the fence, with a 13cm entrance at each end.

How to make a hedgehog gap in different fences

The method depends on what your boundary is made of. Always check with the fence owner before cutting – if it's not yours, you'll need permission.

• Panel fences: Lift out a gravel board at the bottom of a panel and cut a 13cm square notch using a jigsaw. Or simply cut a corner off the bottom of a panel. Sand the edges to avoid splinters.
• Close-board fences: Use a jigsaw to cut a 13cm square hole at ground level. If the fence has a concrete base, you may need to break out a small section with a bolster chisel – wear eye protection.
• Brick walls: Remove one brick at the lowest course to create a gap. If the wall is load-bearing, consult a builder first. Alternatively, install a hedgehog tunnel under the wall.
• Hedgerows: If you have a hedge, you may not need to do anything – hedgehogs will find their own way through. But if it's thick and dense, trim a small arch at the base.
• Gates: Leave a 13cm gap under a wooden gate, or fix a small ramp on either side to help hedgehogs climb over a low threshold.

Make the route safe and inviting

A gap is just the start. Hedgehogs need food, water and shelter to make your garden a worthwhile stop. Avoid using slug pellets – they are lethal to hedgehogs, as are many pesticides. Instead, encourage natural prey like beetles, caterpillars and earthworms by leaving a wild corner, a log pile or a compost heap. A shallow dish of fresh water is a lifesaver in dry weather, but never put out milk or bread – it causes diarrhoea. For shelter, a purpose-built hedgehog house, a pile of leaves or a stack of logs will give them a safe place to sleep. If you have a pond, add a gentle ramp so hedgehogs can climb out.

Team up with your neighbours

One gap is good; a network is better. Knock on your neighbours' doors and explain what you're doing. Most people are happy to help once they know hedgehogs are struggling. You could agree to create a series of gaps along your street, linking gardens into a continuous corridor. Even a few connected gardens can make a real difference. If you live in a terrace, the gaps can run from one end of the row to the other. And remember: a hedgehog highway isn't just for hedgehogs. Frogs, toads, slow worms and even mice will use the same routes, boosting biodiversity across your whole neighbourhood.

Keep the highway open all year

Once your gap is in place, check it regularly. Leaves, twigs and overgrown plants can block the route, especially in autumn. Clear any debris, but do it gently – a hedgehog might be hibernating nearby. In spring and summer, watch for hoglets (baby hedgehogs) that might be exploring. Never use strimmers or hedge trimmers near the gap without checking first. If you need to repair a fence, make sure the gap is reinstated afterwards. A little maintenance now ensures that your hedgehog highway stays open for years to come – a simple, lasting gift to one of Britain's most beloved creatures.