The 13 cm test that decides a hedgehog’s range

A hedgehog can travel more than a kilometre in a night, but a solid garden fence can turn a whole street into a dead end. The practical unit of conservation is not the garden; it is the gap. A 13 cm by 13 cm opening in a fence line is enough for most adult hedgehogs to pass, while still excluding pets and preserving privacy. Where that gap is missing, local populations fragment into small, vulnerable pockets.

Why tidy boundaries become ecological traps

The problem is rarely a lack of insects. It is a lack of connected cover. Hedgehogs forage along hedges, leaf litter and rough grass, then meet kerbs and roads when their route is blocked. Slug pellets and strimmers add secondary risks. The cause is cumulative: sealed fences, paved gardens and night-time traffic. The solution is equally cumulative: one gap, one native hedge, one shallow water dish, repeated across neighbouring plots.

Planning a route with wildzy

A map is only useful if it records the obstacles as well as the habitats. A planning resource such as wildzy can help a household or street group mark fence lines, ponds, compost heaps and road crossings before deciding where to cut a gap. The aim is not a perfect wildlife garden; it is a chain of small, safe connections.

Audit the boundary before changing it

Walk the perimeter at dusk and note every continuous fence panel. Identify at least two potential gap points, preferably away from busy driveways. Check with neighbours before cutting, and line the tunnel with a short pipe if pets or children use the garden.

Pair access with cover

A gap that opens onto bare paving offers little. Place it beside a native hedge, a log pile or a rough grass strip. These features give hedgehogs somewhere to forage and hide within metres of the crossing, reducing the time they spend exposed.

Measure the result, not the intention

Success is visible as use: droppings, disturbed leaf litter, or a night-camera clip. Record sightings monthly and compare them with the pre-change audit. If activity stays flat, check whether lighting, dogs or a blocked second boundary are cancelling the benefit. A corridor is a system, not a single hole in a fence.

FAQ: the details that trip up well-meaning plans

• Is 13 cm always enough? For most adult hedgehogs, yes; young or very large animals may need slightly more, so 15 cm is a safer target.
• Can I use a hedgehog hole in a wall? Yes, if it is at ground level and does not weaken the structure; seek advice for older masonry.
• What about roads? Gaps should steer animals away from kerbs and blind corners, not straight toward them.