Deadly virus attacks wild bird population

A NEW strain of a potentially deadly bird virus sweeping across Britain is believed to have reached Scotland.

Research published yesterday revealed that Avian pox has now been found in common garden bird, the great tit.

While most of the affected birds are in England, two suspected Scottish cases have also been reported, in Perthshire and Glasgow.

The virus has previously been found in milder form in other British bird species, including house sparrows and wood pigeons north and south of the Border.

In great tits, it is far more serious, causing larger, tumour-like growths which can prevent birds from feeding and leave them more vulnerable to predators.

Experts fear that while the disease alone won’t cause the general population of great tits to die out, it could significantly reduce survival of infected birds, whose growth is stunted, making them more susceptible to other threats that could reduce their numbers.

Unlike Avian flu, however, Avian pox is not known to be infectious to people or other mammals.

People in Scotland are being urged to report possible sightings of affected great tits to experts at SAC Consulting at the Scottish Rural University College or RSPB Scotland.

Dr Shelly Lachish of the Edward Grey Institute at Oxford University said: “Although recovery from infection can occur, our results show that this new strain of avian pox virus significantly reduces the survival of wild great tits and has particularly large effects on the survival of juvenile birds.”

She added: “Our models do not predict that this new disease will cause an overall population decline of the species. However, pox-affected populations have lower yearly growth rates. Hence, they are likely to have greater difficulty in recovering from other environmental factors that might reduce their numbers.”

The disease, which has spread rapidly in birds during the past five years from south-east England into central England and Wales, is thought to be carried by mosquitos.

Wildlife vet at ZSL, Dr Becki Lawson said: “Infection leads to warty, tumour-like growths most particularly on the head on the side of the face around the eyes and beak.

“Sometimes they obscure the eyes and often they are featherless, which makes them pink.”

RSPB Scotland has advised people to keep garden feeders clean to help limit the spread of the virus.