Alternatively, build a heap of sticks and leaves specifically as a hedgehog hibernaculum.
Nov 21st is The Day of the Hedgehog. The People's Trust for Endangered Species is holding its annual conference for hedgehogs in Telford - I mean about hedgehogs.
Here's a link to Avon Wildlife Trust's hedgehog booklet - how to build hoghouses, how to feed hogs, how to make your garden hog-friendly.
and here is a link to the British Hedgehog Preservation Society