Testing red squirrels for pox resistance
25 November 2013 Last updated at 07:34 GMT
Red squirrels at a National Trust reserve in Formby have shown the first signs of resistance to the pox virus that has blighted the species, say researchers.
Scientists from the University of Liverpool has studied the squirrels at the site for the last four years.
They found that 10% of the squirrels had pox antibodies in their blood.
Here the team, led by Tim Dale from the University of Liverpool show BBC science reporter Victoria Gill how they catch and examine the animals in order to gather their data.
Video by Miles Massey