An uninhabited island that is so remote a permit is required to visit has been littered with thousands of elastic bands, by seabirds mistakenly thinking they are worms.
Rangers who care for the colony on Mullion Island were initially left scratching their heads by the phenomenon, which has seen coloured bands strewn across the island.
It is thought to be caused by great black-backed and herring gulls mistaking the bands for food while feeding in agricultural fields on the mainland, before returning to deposit them at roosting sites on the island, which is off the Cornish coast.
Experts monitoring the two-hectare rocky outpost found large numbers of tan, yellow and green bands among pellets regurgitated by the birds.
Small bundles of green fishing net and twine were also uncovered among the undigested food, likely mistaken by the gulls for tasty morsels floating on the surface of the sea.
Rachel Holder, area ranger for the National Trust, said: “Ingested plastic and rubber is another factor in a long list of challenges which our gulls and other seabirds must contend with just to survive.
“Despite being noisy and boisterous and seemingly common, gulls are on the decline.
“They’re already struggling with changes to fish populations and disturbance to nesting sites, and eating elastic bands and fishing waste does nothing to ease their plight.
“Places like Mullion Island should be sanctuaries for our seabirds, so it’s distressing to see them become victims of human activity.”
Mullion Island is a small, rocky outpost off the Lizard Peninsula, cared for by the National Trust, that provides a sanctuary for nesting seabirds including great black-backed gulls, herring gulls, cormorants and shags.
Despite public access to the isolated site being forbidden, the effects of human influence are increasingly evident.
The elastic bands are believed to have come from nearby horticultural fields, where they are used to tie together bunches of cut flowers.
One gull was found to have died after becoming caught in a 10cm fishing hook.
Mark Grantham, from the West Cornwall Ringing Group, discovered the bands.
“We first noticed the bands on a monitoring visit during the breeding season and were puzzled why there were so many and how they’d got there,” he said.
“To save disturbing the nesting birds, we made a special trip over in the autumn to clear the litter. Within just an hour we’d collected thousands of bands and handfuls of fishing waste.
“The gull breeding season was disappointingly poor in 2019 and these hidden human pressures are doing nothing to help our seabirds.”
The numbers of great black-backed gull have fallen by 30% in recent years, while the herring gull – the species notorious for pinching food from unassuming tourists – now appears on the UK Red List of Birds of Conservation Concern.
The National Trust is calling on businesses to consider how they dispose of plastic, latex and other materials that could cause harm to wildlife.
Lizzy Carlyle, head of environmental practices at the trust, said: “Single-use materials are having an alarming impact on our country’s most remote places.
“It’s up to all of us to take responsibility for how we use and dispose of these items, whether we’re producers or consumers.”
Chris Thorne, from Greenpeace UK, said: “The human impact on our oceans is evident even in the most remote parts of the UK.
“To discover seabirds on Mullion island picking up fishing gear having mistaken it for food is sad beyond belief.
“Our Government needs to take the problem of ‘ghost gear’, discarded or abandoned fishing equipment, in UK waters seriously before the problem becomes even worse.”