The late arrival of Bewick’s swans in the UK for winter could be linked to warmer weather, experts believe. The first swans – whose appearance traditionally marks the start of winter – arrived at the Wildfowl & Wetland Trust’s Slimbridge Wetland Centre in Gloucestershire on Thursday 16 November. It is the latest the birds have arrived at the site in Gloucestershire since 1965. Although the impact of the weather on bird migration is still being understood, it is thought likely the warmer climate is leading to the swans arriving later and in smaller numbers than in previous years. Experts also believe the mixture of stormy and mild weather in recent weeks has had an impact.