Volunteer birdwatchers across the UK and Ireland will take part this weekend in the six-yearly international swan census, counting whooper and Bewick’s swans. The survey, last carried out in 2020, tracks long-term changes in wintering populations, with whoopers migrating mainly from Iceland and Bewick’s swans from Siberia.
The census spans a vast geographic range, covering whooper swans in Iceland, north-west Europe and the Black Sea region, and Bewick’s swans across central Asia and the eastern Mediterranean. Results in recent decades show sharply diverging trends. The UK’s wintering whooper population has almost doubled to about 20,000 birds over 25 years, while Bewick’s swans have declined dramatically, with only around 700 recorded in early 2025, mostly at a handful of southern English sites.
Climate change is thought to be a key factor behind both trends. Milder winters have boosted whooper survival and breeding success, while similar conditions in northern Europe mean many Bewick’s swans no longer migrate as far west as the UK and Ireland.
