A sudden cold snap is set to bring a late influx of wintering birds on to reserves in the UK, wildlife experts said.

This upcoming cold weather will act as a prompt for birds to move further south . . .

Slimbridge Wetland Centre, in Gloucestershire, added that while the mild winter has so far kept some birds further north, a change in the weather could lead to a delayed migration.

The unusual weather this winter has led to large flocks of waders choosing to stay in the UK in larger numbers than in recent colder winters, but it has also led to smaller numbers of swans, geese and ducks.

Experts are now predicting the cold snap is likely to encourage them to complete the last leg of their migration.

Dave Paynter, reserve manager at Slimbridge Wetland Centre, said: “This warmer wetter winter has been really interesting for birdwatching, contrasting with the past two winters which have been cold and dry.

“This upcoming cold weather will act as a prompt for birds to move further south and the wind direction will create perfect flying conditions.

“This year we have seen higher numbers of waders enjoying the warm wet weather such as flocks of lapwing, dunlin and golden plover, but have so far failed to see the numbers of geese, ducks and swans we would expect.

“This is because the weather has been so mild that they have stopped early on their migration as it is easier for them to find food further north.”

One bird, which staff at Slimbridge are especially keen to see return is the Winterling – one of the 300 or so Bewick’s swans which fly to spend the winter at Slimbridge each year when conditions in their breeding grounds in the Arctic tundra become inhospitable.

If the swan, which would have turned 29 last year, flies on to the reserve she will be the oldest wild swan yet recorded.

The mild wet weather which has dominated UK’s winter is set to end. Instead it will be replaced by colder, dryer days and prolonged easterly winds creating the perfect conditions for migration.