Hightailing along city streets and raiding ponds: otters’ revival in Britain | Wildlife
OhOn a quiet Friday evening, an otter and a fox trot through downtown Lincoln. The pair pass charity shops and down deserted streets, the encounter lit by the safety lights of shuttered takeaways. Each animal inspects the nooks and crannies of the main street before disappearing into the night, ending the improbable scene captured on CCTV last month.
Unlike the fox, the otter is a rare visitor to UK towns and cities. But after decades of intense conservation work, the situation is changing. In the past year alone, the aquatic mammal has been spotted on a river quay at London’s Canary Wharf, dragging a huge fish along a riverbank in Stratford-upon-Avon and raiding garden ponds near York. An otter was even filmed causing chaos in a Shetland family’s kitchen in March.
Janice Bradley, nature recovery manager for the Nottinghamshire Wildlife Trust, says: “Twenty years ago they were almost non-existent. Then we saw them coming up the River Trent from other areas. Today we have records of otters in virtually every river and stream in the county. It’s remarkable.”
No one knows how many otters live in the UK, although it is widely believed that the population has increased, after almost disappearing in the UK’s polluted waterways in the mid-20th century. Some naturalists estimate there are 11,000 nationwide, but acknowledge that this is a guess.
In the 1970s, investigators searched almost 3,000 sites across the UK but found the animals in only 6% of them, mainly in strongholds in Scotland, Wales, Norfolk and southwest England. Today, they are widespread and use their sensitive whiskers and webbed feet to hunt in waters throughout the country.
Their return is a fragile story of improved water quality, conservationists say. Discharges of industrial waste from factories and toxic pesticides ravaged fish populations in British rivers in the 19th and 20th centuries, with disastrous consequences for otters, who ended up consuming many of these toxins.
A ban on harmful pollutants, improved water quality – despite more recent problems with sewage dumping by water utilities – and a targeted reintroduction campaign in the east of the country have all contributed to their return.
Jon Trail, of the Yorkshire Wildlife Trust, said: “I think the surveys in the 1970s were a lightbulb moment for people, when they realized that otters had been seen historically and they couldn’t see them anymore.
“There are old documents detailing encounters between otters and naturalists, but people hadn’t seen them for years.
“It’s been a slow burn. Otters usually have one, two, sometimes three pups, which the female takes care of for a year, so the recolonization rate is slow. Over 10 years, you might only have five or six pups, so it was always going to take a little while. But now we’re past a tipping point.”
Not everyone is happy about the return of the otter to the UK. Fishermen blame them for devouring fish in their favorite spots, accusing the animals of disrupting the balance of the river, but many experts say this claim is exaggerated.
Despite their traditional depiction as feeding only on fish, otters feed on a wide range of rodents, birds and amphibians, and analysis of their diet shows that they rarely prey on the large fish prized by the fishing community.
Dr Elizabeth Chadwick, head of Cardiff University’s Otter Project, which tests dead otters across the country to monitor pollution levels, says: “When it comes to native fish species, there is no evidence that otters are responsible for wiping out stocks. This is partly a misunderstanding, but it also reflects limited resources.”
“In British rivers, fish stocks are limited in some places. It’s not because otters have recovered,” she explains.
The Otter Project’s findings paint a complicated picture of recovery, showing that heavy metals, the “forever chemicals” Pfas and pesticides continue to accumulate in mammals. But amid growing concerns about the health of the UK’s rivers, Chadwick says the otter could become a symbol of the change many are calling for.
“Otters are a really good way to monitor the health of our waterways. A lot of chemical pollution builds up in an animal over time. They’re often present in trace amounts in the water, so we can’t detect them in samples. But if you test the top of the food chain, they become detectable,” says Chadwick.
“If we can use otters as a kind of charismatic ambassador for river health, that can be a really powerful thing.”
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