The European otter (Lutra lutra) has made a remarkable recovery across the UK since near-extinction in the 1970s, when water pollution and persecution had reduced populations to a few refugia. But road mortality at river crossings remains the leading cause of adult otter death in England and Wales.
Otters killed by road traffic die from traumatic blunt force injuries — impacts at vehicle speed cause fatal internal injuries. Young otters dispersing from their natal territory are particularly vulnerable, as they navigate unfamiliar road networks while establishing new territories. Cubs orphaned when mothers are killed by cars require intensive rehabilitation at wildlife centres, hand-rearing for months before release. Water pollution causing fish kills reduces prey availability and forces otters to travel longer distances along roads to find food. Otter ledge installation under road bridges is one of the most cost-effective wildlife welfare infrastructure investments available.