Climate change and rising temperatures are leading to fewer wild swans returning to the UK in winter, according to the Wildfowl and Wetlands Trust (WWT).

At Slimbridge, Gloucestershire, the population of Bewick’s swans has declined by 86% over nearly 50 years.

These birds traditionally migrate from northern Russia to the UK to escape harsh Arctic winters. However, due to milder conditions, they are stopping their journeys earlier, finding ice-free wetlands along the way. This year, only 87 Bewick’s swans returned to the reserve, with no cygnets among them.

WWT Slimbridge has studied Bewick’s swans for about 50 years, documenting over 10,000 individuals. It is one of the longest-running studies of a single species.

However, warming temperatures in Europe are altering their migration patterns. Recent data indicates that over 7,000 swans “short-stopped” their journey this winter, staying in Denmark, Germany, and the Netherlands instead.

Martin McGill, WWT Slimbridge’s reserve manager, called the decline “concerning.”

“Bewick’s swans are hugely important to our history here at WWT, and it’s almost impossible to imagine Slimbridge without them,” he said.

“We love welcoming them back each winter so it’s terribly sad to see so few of them this year and without any cygnets.”

Beyond climate change, the swans also face threats from toxic lead poisoning and illegal hunting along their route.

“We make sure the Bewick’s swans have everything they need while they’re with us, but we know they face challenges on their migrations and at their breeding grounds,” Mr McGill continued.

“We need more wetlands to help us reverse the impacts of climate change and prevent situations like this from happening in future.”

In response, WWT is leading a coalition of charities urging the UK government to ban the sale and use of lead ammunition. This measure aims to protect Bewick’s swans from unnecessary suffering and ensure their survival.