Over Christmas, our reserve wardens have been busy lacing the lake shore with raw potatoes, carrots and parsnips as an extra tasty treat for the swans. During weeks of sub-zero temperatures, their natural food became increasingly scarce as the grass remained frozen and under snow. The supplementary daily feeds of wheat therefore proved very popular!

After the recent thaw, the grass will need time to improve again, but in the meantime, root vegetables are on the menu!

The swans have strong jaw muscles which enable them to bite firmly while a nail on the tip of the bill and a prickly tongue enables them to tackle tough vegetables as well as vegetation. Although Bewick’s swans have traditionally fed on aquatic vegetation in wetland habitats, habitat changes in the mid-1900s as a result of the drainage of wetlands and intensification of agriculture, encouraged many to also feed on improved pastures and arable land.

This has certainly been the case in Norfolk,
the ‘bread basket’ of the UK, where most birds now feed on sugar beet, winter cereals, potatoes and improved pastures. Slimbridge swans feed mostly on vegetation found on the reserve such as common ryegrass and marsh foxtail (a diet which is supplemented by grain), and so the root vegetables are providing a welcome change.

A total of 223 swans were recorded at the feed this morning, including 40 cygnets.

The big freeze continues and the swans keep flooding in! This December is set to be the coldest in the UK since records began in 1910, according to the Met Office. Food for the swans is becoming increasingly scarce as wintering sites across Northwest Europe remain under deep snow. A total of 318 birds have now visited Slimbridge this winter, still the highest number since 1991 when 356 had been recorded by the same time. With temperatures plummeting to -10C in recent nights, the swans have been spending much of each morning ‘de-icing’ their feathers by thoroughly preening them!

Old favourite Widemouth has returned for her twelfth winter, along with mate Winney. Both are ringed (TUV and BCH) and have been spotted stopping off at wintering sites in Holland and Germany on migration in the past. When in the UK, they sometimes enjoy visiting Welney and regularly take day trips away to Walmore Common, an alternative feeding (and sometimes roosting site) around seven miles north of Slimbridge.

The highest count of the winter so far was recorded this morning, with 259 birds (including 36 cygnets) observed jostling for position at the feed!

A total of 261 Bewick’s swans have visited Slimbridge so far this winter, the highest number seen here by 10 December since 1991, when 333 were recorded during another period of cold weather where temperatures similarly dipped to -8C. The freezing conditions and northerly winds over the past two weeks are likely to have encouraged more swans to fly further west in search of food. The swans find it harder to access their usual diet of grass, cereals, root crops and pond weeds when frozen and snow covered. Not only will they be finding it harder to find food, they will also be expending more energy to maintain their body temperature.

We try and help the birds as much as possible and all 197 recorded today have been eagerly making the most of their feeds and have been able to continue to bathe and drink in the ice-free pools of water left by our water bubbler system. With the fields starting to defrost, many of them are now returning to the fields in large groups to feed.

We were thrilled to see the return of Winterling this morning, who at the age of 28 years, has broken the record for the oldest swan known to have visited Slimbridge! Winterling first visited the reserve as a cygnet in 1982 with her parents Albert and Rachel, and after first learning the long 2,500 mile migration route from breeding grounds in arctic Russia, she has returned most years since! Although a few wild Bewick’s swans reach their early to mid-twenties, Winterling is the oldest swan to have visited Slimbridge in 10,000 individual birds studied here. Furthermore, she is edging her way towards equalling the world record for longevity, reached by a ringed bird who was 29 years old when found dead in 1993.

During the 28 years, we have gained extraordinary insight into Winterling’s life, thanks to her remarkable survival and WWT’s unique ability to monitor her intensively through bill pattern recognition and ringing methods. We have learnt that she has outlived three mates, returning alone this winter for the fourth year running. She has brought only four cygnets back to the reserve and was frequently spotted in the Netherlands during autumn migration before losing her ring in 1996. Several winters have also been spent at Welney.

Following the radiation leak at Chernobyl in the Ukraine in April 1986, Winterling’s radiation levels were tested when she was caught at Slimbridge the next winter. Although it was thought that the swans would have migrated through the Baltic before the disaster, there were concerns that some birds may have been affected by the incident had their migration been delayed. Fortunately, radioactivity was not detected above background levels in any of the 46 swans tested that year. Despite gaining such a detailed and fascinating picture of Winterling’s history, there will be much of her life that only she will know about, and in over 143,000 miles of flying, she must have seen some sights!

With the swans flooding in on the north-easterly wind, a total of 164 birds have now been recorded at Slimbridge so far this winter which is higher than the five-year average for this time of year (100 birds).