Freezing weather in northern Europe has led to more than 10,000 swans, ducks and geese seeking refuge in the Evros Delta in northeastern Greece, animal experts told Kathimerini yesterday. «The phenomenon of mass flight, especially of swans this winter compared to last year, is down to the freezing weather in Europe,» the head of the Hellenic Wildlife Hospital (EKPAZ) said. Up to 11,000 birds, mostly swans, from Scandinavia, Siberia and central Europe, have arrived in the delta since last week. They headed south in search of food and warmth. EKPAZ has treated 14 swans since last week and found another 40 dead in Evros. It is thought the cold weather and exhaustion from the long journey were too much for some. The arrival of the birds has put local authorities on heightened alert for bird flu. Officials are said to be checking daily that chickens are kept in their coops.