Following on from my piece on toad crossings, today's BBC Radio 4 nature program concerned snake crossings in the US. These tiny, harmless snakes are often mistaken for sticks and ran over.

I particularly liked the idea of coming up with road measures, such as speed bumps, to create crevices for snakes to cross safely in. Similar projects have been investigated for mammals such as tunnels and bat bridges, not always successfully.

We can make some use of these unfortunate casualties. The People's Trust for Endangered Species run an annual survey, where members of the public report sightings of dead mammals called 'Mammals on Roads.' From this we are able to get information on species distributions and population declines. I'm lucky enough to have access to these data, and am currently analysing hedgehog population trends since 2001.

You can take part in the survey annually from July