Bewick's swans used to spend a lot of time in Ireland and Britain and the Netherlands, but scientists say they have been moving east into Germany. They spend less time in their winter feeding grounds than they did in 1970. Scientists say they are following the changes in temperature in Europe. The scientists found that individual swans do not change where they like to go during their own lifetimes. Instead, different generations of swans go to different places from their parents and grandparents.