Article on BBC site looks at the Curious Case of the Scottish Swan with H5N1.
According to bird migration experts, the bird may not be native, and is a mute swan from the Baltic region or Black Sea that journeyed to the UK to escape a cold snap.

“This swan could have been part of a hard weather movement,” Grahame Madge, from the RSPB, told the BBC News website.

“This is where you get hard weather in the Balkans or the Black Sea and water freezes over, meaning birds that need access to fresh water need to move – sometimes a few miles, sometimes 100 miles.”

Mr Madge believed that a hard weather movement could have been responsible for the spread of H5N1 to France and Germany confirmed in February.

“The possibility is that this swan could have been part of the tail end of this movement, and might not have been a British-born bird at all.”

Martin Fowlie from the British Trust for Ornithology (BTO) also suggested that this might be the case, and also raised the possibility that the swan may not have even died in the UK.

“It might have been a mute swan from Eastern Europe that had flown west and might have died in the North Sea and had been washed in,” he said.
Virus’ route to UK still unclear

Tests show the virus is related to that found in Germany: