Roadkill spotters are wanted to help place warning signs in the right places.
Volunteers are needed to record sightings of mammals, dead or alive, as part of an annual road survey.
Wildlife charity People’s Trust for Endangered Species (PTES) is asking families going on summer holidays or day-trips, car-sharing commuters and anyone else using Britain’s roads, to record sightings of mammals.
The data collected helps conservationists to see changing population trends and identify where action is needed most and for which species.
People can submit the records via the free Mammals On Roads app – available on both Apple and Android smartphones via Google Play and the App Store.
David Wembridge, mammal surveys co-ordinator, said: “Mammals On Roads began over 18 years ago, and though no one likes seeing roadkill, recording such sightings every year tells us how wild mammals are faring in the surrounding landscape.
“For example, thanks to the many volunteers who have submitted records over the last two decades, we found out that hedgehog numbers are plummeting.
“Now, we’re doing everything we can to help this species, but we wouldn’t have known they were in trouble without volunteers helping us.”
The wild mammals most likely to be spotted include hedgehogs, badgers, rabbits, foxes and deer.
Last month the Department for Transport announced the launch of a new mammal road sign, featuring a hedgehog.
The new sign will remind road users to keep an eye out for small wild mammals in order to lessen the number of collisions involving animals each year.
The data collected via PTES’ Mammals On Roads survey will help inform where these new road signs should be placed, in areas where collisions with animals are highest.
Mr Wembridge added: “Taking part in Mammals On Roads can really make a huge difference and helps ongoing conservation efforts by building a country-wide picture of how mammal numbers are changing.
“Helping mammals couldn’t be easier, so we hope our regular recorders and lots of new ones will take part this year.”