Road traffic is putting smaller hedgehog populations at risk of collapse

A new study involving the University of Cambridge has found that road traffic kills between 15-29% of hedgehogs in local populations each year. 

The study, funded by The British Hedgehog Preservation Society and People’s Trust for Endangered Species, investigated how road traffic deaths impact local hedgehog populations of different sizes in the short and longer term.

It found that despite having the highest number of traffic-related deaths, larger hedgehog populations are able to offset these losses through higher overall survival and reproductive rates - plus the fact that most hedgehogs killed on roads are males, which move around more than females in the search for mates.

However, in smaller populations with fewer than 15 individual hedgehogs, even a small amount of roadkill each year has a significant impact and cannot be offset through reproduction. 

To get their results, the researchers studied four hedgehog populations in villages and towns in Nottinghamshire, selected to be representative of wider populations in terms of habitat and road densities. They walked 838km of survey routes, measuring population size along with reproductive rates and adult and juvenile survival rates.

The team also completed 269 roadkill surveys over 18 months, aiming to find every hedgehog roadkill within and between the study sites, while recording the location, age and sex of those found. 

Using their results, the team then modelled future scenarios to estimate how road deaths could influence long-term population persistence, particularly alongside future expected increases in UK traffic levels.

Based on an estimate that around 50% of hedgehogs could be killed on roads each year, the two smaller populations would halve in size within two years, and could face local extinction after nine years. Even for the larger populations, a 40% mortality rate would be sufficient to cause a decline of 40% in one population and 51% in the other within 50 years.

The study is published in the journal Animal Conservation.

This research shows the importance of bolstering smaller hedgehog populations so that they can better withstand traffic-related deaths. Larger areas of good habitat are also needed to support larger numbers of hedgehogs. Simple actions can help – such as leaving some wild areas in gardens, to provide food and nesting sites for hedgehogs. 

It is also important to improve habitat connectivity, for instance creating 13cm x 13cm square ‘Hedgehog Highways’: gaps in fences and walls that enable hedgehogs to move freely and safely between gardens and neighbouring populations, to increase populations’ viability without the need to cross roads. 

Dr Silviu Petrovan, Assistant Research Professor in the Zoology Department at the University of Cambridge who was involved in the study, said: “These findings show that the decline in hedgehog populations in rural areas is likely to be exacerbated by roadkill, where many threats relating to land management have already made large areas of our countryside less suitable for one of our nation’s favourite mammals.”  

Petrovan, who is also Conservation Strategy and Research Manager at the People's Trust for Endangered Species, added: “Effective prevention of road mortality for hedgehogs is likely to be difficult given the vast network of existing roads, meaning that we need to consider widespread conservation measures to enable our rural hedgehogs to become more resilient to this important additional threat.”

Fay Vass, Chief Executive at The British Hedgehog Preservation Society, said: “This unique study not only looks at the number of hedgehogs being killed on roads, but examines the wider picture to help us understand how this can impact hedgehog populations now and into the future. We know that hedgehog populations across the UK are in decline – and research like this is vital in helping us understand the underlying causes so we can reverse this worrying trend.”

The study was led by conservation scientists at Nottingham Trent University, and involved the University of Cambridge, University of Reading and Cardiff University.

Reference: Moore, L.J. et al: ‘Beyond the individual: multisite population-level consequences of road mortality on a declining mammal.’ July 2026, Animal Conservation. DOI: 10.1111/acv.70082

Adapted from a press release by the British Hedgehog Preservation Society.