UK otter populations have recovered strongly since the 1970s pesticide crisis, but road mortality remains a significant welfare burden particularly for dispersing animals.
Otters killed by vehicles suffer traumatic death; those injured and not killed immediately face prolonged suffering before death or rescue. Young dispersing otters unfamiliar with road hazards are most vulnerable. Habitat fragmentation forces otters to cross roads in unsafe locations when road bridges lack suitable safe crossing points. Retro-fitting otter ledges to existing bridges is a highly effective and welfare-positive intervention that has been shown to reduce mortality substantially.