Now that spring has arrived, a wildlife group is calling on garden-owners in France to take part in a hedgehog survey.
The Ligue pour la Protection des Oiseaux (LPO) is better known for its work with birds, but it has also started a long-term study on the welfare of hedgehogs and other animals as part of wider environmental concerns.
Its first hedgehog mission count took place last year - and already some 900 people have signed up to be involved in the survey in 2021.
Those who want to take part should first visit the LPO website to find out about the equipment needed, including a tunnel. The tunnel is available to buy on the site but can also be made at home.
Baited by cat food at one end, the animal enters the tunnel, walks on a strip of safe, charcoal-based ink and leaves its prints on a sheet of white paper as it passes.
The next morning, volunteers should photograph the animal prints and upload them on the site, where they can be seen by other participants and examined by experts.
The experiment should be repeated for five nights in a row - and then again after a six-week break, so that experts can build up a longer-term picture. In total, the tunnel should be outdoors for about 20 days a year.
It is hoped that volunteers will take part for several years. The annual count is intended to take place every year for a decade.
Hedgehogs have been classified as a ”protected species” in France since 1981. A similar survey in England found that animal numbers had fallen by a third over a period of 20 years.