A family of swans have had to be rescued from the River Lea in east London after getting covered in cooking oil—but a cygnet was seen dead in the water close by.

East London Advertiser: Bagging up... Swan Sanctuary rescueing contaminated birdsBagging up... Swan Sanctuary rescueing contaminated birds (Image: Andrew Messios)

The swans were spotted in difficulty on the riverbank at Hackney Wick by Lucy Stein near her home, who alerted the Swan Sanctuary.

The three adults and a cygnet were struggling with their feathers caked in the oil.

They were taken to the Swan Sanctuary in Shepperton, Middlesex, to be cleaned up and put on a vitamin-rich diet to help their recovery.

The sanctuary has since issued a warning about pollution in the river affecting wildlife.

East London Advertiser: Ready to be transported to Swan Sancrtuary rescue centreReady to be transported to Swan Sancrtuary rescue centre (Image: Andrew Messios)

“Cooking oil unfortunately is not a rare event on the Lea,” sanctuary volunteer Gill Walker said.

“The oil sticks their feathers together, so they lose their waterproofing and begin to soak up the water, which weighs them down.

“The birds lose their insulation from the cold as well, when they start furiously preening their feathers.”

This leaves the swans particularly vulnerable to hypothermia in the winter months, as well as predators while they are stranded on the banks.

East London Advertiser: Lea River swans in recovery at sanctuary in SheppertonLea River swans in recovery at sanctuary in Shepperton (Image: Andrew Messios)

Gill, who collected the swans and drove them to Shepperton, has been busy rescuing swans in London over the holiday period.

“It’s not unusual to take in 20 or 30 swans that have been contaminated,” she added.

But the rescue over Christmas was not the first time the sanctuary had been called out to the lower Lea River.

Thames21 environment charity’s Ben Fenton is urging households to avoid pouring cooking oils down the sink or down drains.

He said: “Cooking oil reaches our rivers when it’s been dumped in drains. People don’t realise this leads straight into our rivers.”

It is impossible tracing the source of oil entering the drainage system in most cases.

The rescued swans from the River Lea, meanwhile, are on a recovery programme at the Swan Sanctuary, ready to be returned to their river territory at Hackney Wick in time for the breeding season.