Image copyright Sam Hobson/WWF Image caption Sam Hobson witnessed rescuers putting their lives at risk to save this bird's life

A photographer who took an image of a gannet trapped in a net says a tiny island off the Welsh coast has become a "living hell" for birds living there.

Sam Hobson captured the moment on Grassholm Island, eight miles off Pembrokeshire, which has an estimated 20 tonnes of plastic on it.

Mr Hobson said gannets were using some of the waste in their nests.

An RSPB Cymru spokesman said marine litter was a "serious threat" to seabirds on Grassholm and elsewhere.

Mr Hobson, a Bristol-based wildlife photographer, captured the image when he went along on a rescue mission to cut free entangled birds on the RSPB reserve.

Image caption RSPB Grassholm Island lies eight miles off the coast and is home to a colony of gannets

The trips are led annually by Greg and Lisa Morgan, RSPB wardens for nearby Ramsey Island.

Mr Hobson said gannets fly out to sea and pick up seaweed for nesting, but that also comes with a lot of plastic material.

"The gannets line their nests with these man-made plastic fibres and their nests become death-traps, entangling adult birds and juveniles as they develop inside the nest," Mr Hobson said.

"This panicked adult gannet struggled as it dangled from a cliff side, with ropes twisted around its neck like a hangman's noose.

"The brave volunteers risked their own lives to creep to the edge of the cliff top and rescue this bird from its death sentence."

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His photograph was used in a WWF photo series which illustrates natural problems highlighted in a UN report.

The report found one million animal and plant species are now threatened with extinction due to humans.

The Global Assessment report, compiled by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), runs to 1,800 pages.

The World Wide Fund for Nature (WWF) gallery calls on world leaders to "act now and save our planet" in response to the IPBES report.

It added that Wales was "one of the most nature-depleted countries in the world with hundreds of species at risk of disappearing".

An RSPB Cymru spokesperson said marine litter was a "serious threat" to seabirds on Grassholm and elsewhere.

He said that on neighbouring Ramsey Island, RSPB staff had freed more than 600 birds from "litter entanglement" since 2005 but others had not been so lucky and die "tethered to their own nests".

"We have looked at removing all the plastic from nests on the island, but this would be an impossible task and would destroy the structure of this long-established colony," he said.

"Freeing individual birds is the most viable option for our staff in the short term."