At the moment the many thousands of whooper and Bewick swans, the true wild swans as distinct from the semi-domesticated mute swans seen on ponds and in parks, and which migrate thousands of miles to Britain from the Russian tundra and Iceland for overwintering in Scotland, have not yet taken off for their breeding grounds in the far north.

But the graceful mutes, identifiable by their “S” shaped necks as distinct from the straight necks of the wild species, do mix with the others. The three species socialise at a number of sites, including a large population at the harbour in Broughty Ferry.

Additionally, it is almost certain that herring gulls, scavengers of the sea, and crows would have been feeding on the decomposing swan at Cellardyke, suggesting the virus may well have transmitted to other species of bird.

Scotland hosts large populations of geese during the winter, which share breeding grounds and flight paths with the wild swans.

Although they are understood to be hardier than the swan population and no evidence has come to light that they may be harbouring the virus, some wildfowl experts are convinced it is only a matter of time before they succumb also.

Medical experts believe the virus at present poses no threat to human health. Infection in the Far East, where most human fatalities have occurred, has stemmed from close physical contact with chickens or people being in enclosed areas with infected fowl for long periods.

However, experts fear the virus could mutate and in its new form trigger a bird flu pandemic, potentially putting many thousands of lives at stake, not to mention the disastrous effect such a threat could have on Scotland’s poultry industry.

Alan Stewart, Tayside Police wildlife and environmental officer, confirmed today swans appeared to be more vulnerable than other wild bird species, but wildfowl as a whole seemed to be more susceptible than other members of the bird family.

While the Cellardyke swan was found near the foreshore, it’s likely there will be more dead swans or geese picked up in the near future on the many ponds and inland lochs in Tayside, which attract many thousands of migrants every autumn.

“We are hoping this is not going to be the virus which affects humans and there are a number of bird flus in the population which are not particularly contagious,” said Mr Stewart.

“There was an alarm in Orkney recently when a number of chickens died, but their virus was not related to the one causing the problem in the Far East.”