Study could save British red squirrels

1 October 2009 by Tamera Jones

Scientists will today begin a pioneering project which could ensure the long-term survival of British red squirrels.

Red squirrel

Although grey squirrels have slowly forced reds out of southern Britain since their introduction more than a hundred years ago, a region of Merseyside in northern England is one of the reds' traditional strongholds.

The site has long been home to a buoyant population of red squirrels, but there was always the risk that squirrelpox virus would turn up. Now it has.

An outbreak of the virus at the National Trust managed site at Formby started in November 2007 and has severely dented red squirrel populations in the region. Some areas have seen their numbers drop by 90 per cent, although more recent anecdotal evidence suggests numbers have now stabilised.

If nothing is done, red squirrels will almost certainly disappear from the Merseyside area.

- Professor Mike Begon, University of Liverpool

"We have no idea if this is because a few red squirrels have built up immunity to the virus," says Professor Mike Begon from the University of Liverpool.

The outbreak gives researchers a unique opportunity to study exactly how the virus spreads between red squirrels. Scientists think the virus is passed from grey squirrels to red squirrels "although we're not certain how," Begon quickly adds. But whereas the virus is usually fatal for red squirrels, greys don't appear to be affected.

"This may be one reason greys have been so successful in this country. Until around ten years ago, the conventional view was that the greys are bigger, more aggressive and out-competed the reds. It may not be that simple," says Begon.

"Our first priority is to see is the surviving reds are carrying antibodies to squirrelpox virus and then further down the line, if we find out something about how the virus spreads, we'll be in a much stronger position to help protect red squirrels."

The findings could be just what conservationists need in their battle to halt the spread of the virus.

"If nothing is done, red squirrels will almost certainly disappear from the Merseyside area," adds Begon.

The study is the subject of a NERC funded PhD project, also supported by the National Trust, based at the University of Liverpool. It will be the first time scientists have tracked in real-time the progress of a squirrelpox virus outbreak.