Why a Small Gap Makes a Big Difference

Hedgehogs are in trouble. Numbers in the UK have fallen sharply over the past few decades, and the reasons are familiar: loss of hedgerows, busier roads, tidy gardens and fewer places to shelter. What many of us don't realise is that our own fences play a quiet part in the problem. A hedgehog might need to travel a kilometre or more in a single night to find enough beetles, worms, slugs and caterpillars. It can cover a surprising amount of ground, but it cannot walk through a solid wooden panel.

A typical suburban garden is a decent habitat on its own. A whole street of them, joined together, is a proper landscape. The trouble is that our boundaries carve that landscape into small, isolated islands. A hedgehog trapped in a single garden will struggle to find enough food, and it may never meet another hedgehog to breed with. The fix is beautifully simple, and it costs almost nothing.

What Counts as a Hedgehog Highway?

A hedgehog highway is simply a gap at ground level, roughly 13 centimetres by 13 centimetres (about five inches square), that lets a hedgehog pass from one garden to the next. That size is deliberate. It is large enough for a full-grown hedgehog, even a chunky one, but small enough that most cats, rabbits and foxes will not bother squeezing through, and it looks neat rather than gaping.

It does not need to be a dramatic hole. In many gardens, the easiest option is a gap under a gate, or a notch cut out of a timber or concrete gravel board. If you have a chain-link or wire fence, you can simply peg the bottom edge up slightly and train the grass to grow around it. If you have a brick wall, a single missing brick at the base does the job admirably.

One gap is a start, but the real value comes from linking several gardens. Three or four neighbours with matching gaps create a corridor that turns a row of back gardens into a genuine route.

Choosing the Right Spot for Your Gap

Placement matters more than most people expect. A hedgehog will happily use a gap that opens onto cover, and will avoid one that dumps it out in the middle of an open lawn with nowhere to run. Look for a spot where there is already a shrub border, a hedge, a log pile or a compost heap on both sides of the fence line.

• Line it up with existing cover on your side and, if you can, on your neighbour's side too.
• Avoid corners where a road runs close by. There is no point guiding a hedgehog towards traffic.
• Keep it away from where a dog patrols or where a pet is fed outdoors.
• Steer clear of a pond edge unless the pond has a gentle escape ramp at one end.
• Pick a spot you can see from the house, so you can keep an eye on it and clear it when needed.

How to Cut a Hedgehog Gap Safely

You will need gloves, safety goggles and, for concrete, ear defenders. A bolster chisel and a club hammer will get through a concrete gravel board; a pad saw or hole saw handles timber panels; an angle grinder makes quick work of concrete but kicks up a lot of dust, so wear a mask and keep the cut damp if you can.

Work methodically. Mark out your 13 centimetre square with a pencil or marker pen, checking with a tape measure rather than guessing. Score along the line before you cut, then work steadily around the edges. Sand or file the cut edges so nothing sharp is left exposed, and take care not to cut into a fence post, which would weaken the whole run. If you are cutting into a concrete base, go slowly and let the chisel do the work rather than forcing it.

Before you start, check for any cables or irrigation pipes you may have run along the base of the fence yourself. Fence lines rarely contain services, but it is worth a moment's thought. Once the gap is open, a short length of pipe or a couple of bricks laid on their sides can line it neatly and stop soil and grass closing it up over time.

Making the Route Safe Once It's Open

A gap is only useful if the garden on either side is worth visiting. A few small changes make a real difference to whether hedgehogs thrive once they arrive.

• Bin the slug pellets. Metaldehyde is lethal to hedgehogs, and slug pellets also remove the very food they came for. Use nematodes, beer traps or hand-picking instead.
• Leave a shallow dish of fresh water out, especially during dry spells. A saucer of water is more valuable than most people imagine.
• Build a wild corner. A pile of logs, a heap of leaves or a compost bin gives hedgehogs somewhere to nest and hibernate.
• Check before you cut. Strimmers, mowers and garden forks cause terrible injuries. Look inside the compost heap and under the bonfire pile before you disturb them.
• Feed properly if you feed at all. Meat-based cat or dog food and hedgehog biscuits are fine. Never bread and milk, which causes serious stomach problems.

Bringing the Neighbours On Board

The most effective hedgehog highway runs through several gardens, so it is worth knocking on a door or two. Most people are happy to help once they understand that a five-inch gap will not let the dog escape or the children wander. Explain that you will do the work, that it is discreet, and that their garden benefits too, because a hedgehog eats its way through a great many garden pests.

Once the gap is in, mark it in some way so it does not get blocked by a future owner or an over-enthusiastic tidy-up. A small painted line, a label on the inside of the fence, or a note in the shed is enough. If there is a local wildlife group nearby, they may already be mapping hedgehog highways in the area, and your gap could join a much larger network.

Then all that is left is to wait. Hedgehogs are creatures of habit, and a well-placed gap may go unvisited for weeks before you notice the tell-tale signs: droppings on the lawn, a rustle in the border after dark, or a small, snuffling visitor caught in the beam of a torch. It is a small piece of work for a very large reward.