Record numbers of swans have been wintering in the Fens this year, with more than 13,000 counted on one day at the on the Ouse and Nene Washes.

A co-ordinated count by the Wildfowl and Wetlands Trust (WWT) and the Royal Society of the Protection of Birds (RSPB) earlier this month revealed the record numbers which included 7,296 Whooper swans – far higher than the 5,000 normally counted in the area.

The rest of the swans counted were Bewicks, whose numbers are declining while Whoopers appear to be increasing.

The Fens are an important network of wetland sites and is home to the largest concentration of wintering Whooper and Bewicks in the country. The Ouse and Nene Washes have parts owned and managed by the conservation organisations.

Experts are unsure as to what may have caused the upsurge in numbers, but the extreme winter weather in other parts of the country may have played a part.

'The Fens was one of the few areas to remain free from snow, and more severe weather elsewhere in the UK may have pushed the Whoopers further south and east than they would normally travel.

A swan, with the identification ring CHZ, which normally winters in Ireland, called into WWT Welney for the swan feeds and there may well be many more swans in similar situations,' said John Smith, WWT conservation warden.

Careful management of the land in The Fens allows the swans, which travel from Iceland and Russia each winter, to safely feed and roost so they are healthy for their return to the Artic for the breeding season.

During the months of October to March they join the resident mute swans on wetland sites such as the Ouse Washes.

'The wetlands in this area are incredibly important to these birds for roosting and the surrounding arable land provides a much needed food source in the form of waste potatoes, grain and sugar beet tops from the recent harvest,' said Mike Burdekin, RSPB warden.

Each winter the birds are carefully monitored in counts such as the recent on on January 18.

A small selection of birds are caught to have identification tags put on their legs so scientists can identify individuals, track their progress and learn about their behaviour.

Monitoring the status of both Bewicks and Whooper swans is critical to their conservation.

Both species are amber-listed on the birds of conservation concern list, which also reflects the importance of the wintering grounds in The Fens to their survival.

'Understanding and addressing the ongoing threats to their future is of the utmost importance,' said the WWT.

Members of the public can observe the birds at WWT Welney and RSPB at Welches Dam, near Manea.

The Welney site run swan feeding events until March when expert commentary by wardens accompanies the spectacle of swans and other wildfowl being fed close to a hide.

The evening feeds are held under floodlights to create a real spectacle for visitors.

Special events at the reserve, such as Swans Awake and Bewicks' Flight, give people the chance to get even closer to the birds and witness them flying out from the reserve at dawn and back in the evening.

For further information about Welney see: www.wwt.org.uk/welney and for information on Welches Dam see: www.rspb.org.uk/reserves/ guide/o/ousewashes/