What lockdown taught us about roadkill

UK-wide lockdowns gave scientists a unique opportunity to observe wildlife with the absence of traffic, shedding light on what characteristics and traits make iconic British species - like badgers and pheasants - more likely to be involved in collisions with vehicles.

Researchers at The Road Lab, based at Cardiff University, used data of roadkill records to assess the 19 wildlife species most frequently involved in vehicular collisions, to see which exhibited changes in road mortality during two major lockdown periods (March- May 2020 and December 2020 - March 2021). By comparing lockdown rates to the same time periods in previous years (2014-2019), they were able to identify the traits that put species at higher risk of becoming roadkill.

Sarah Raymond, research student at Cardiff University’s School of Biosciences who led the research, said: "Wildlife-vehicle collisions were 80% lower during the lockdowns across all species, which is not surprising given the dramatic decrease in traffic. But lockdown gave us experimental conditions that wouldn’t have been possible in any other time. The absence of cars on the road gave us a chance to see what characteristics and traits of UK wildlife put them at higher risk of being hit by a car.

"During lockdowns, we found that there were fewer records of nocturnal mammals, animals that visit urban environments, mammals with greater brain mass and birds with longer flight initiation distances.

"Species that have several of these traits - such as badgers, foxes and pheasants - are more likely to be hit by cars and have the highest mortality rate in normal traffic levels. These species therefore appear to have benefited from the lockdowns the most, and so suffer most during ’normal’ times."

The temporary reprieve from traffic during lockdowns allowed scientists to pinpoint the wildlife most at risk from collisions. The data can help inform wildlife conservation in a road-dominated landscape.

"The UK is a country where roads cover 398,359km in length and there are 39.2 million car owners. This study seized the unique opportunity to see what happens when this road-dominated landscape fell silent. We revealed the impact that these vehicles are having on our much-loved British wildlife species, not only that, but that the risks are trait-based.

"By understanding what makes certain species more vulnerable to becoming roadkill, this can help us identify more focused conservation efforts and hopefully help towards the protection of British wildlife," added Sarah.

The study was a collaboration between Cardiff University, University of Liverpool and University of Exeter. The paper, The impact of the COVID-19 lockdowns on wildlife-vehicle collisions in the UK, is published in Journal of Animal Ecology.