The pine marten - declared extinct in England a decade ago - is making a comeback in North Yorkshire, wildlife experts believe.
New sightings on the edge of the North York Moors have prompted the Forestry Commission to set out feeding tubes to collect hair samples for DNA analysis.
They hope that bait - including the mammal's favourite jam sandwiches - will lure the animals into the tubes.
EDIT
The Forestry Commission has teamed up with the Moors National Park, Hull University and local conservationists to find conclusive evidence that pine martens have ventured south from their refuge in the Scottish highlands. Brian Walker, Forestry Commission biodiversity officer, said: "My gut feeling is that we do have pine martens in this part of North Yorkshire. "Over the years we've had many sightings, some cases of mistaken identity, but others very convincing. "One of these came in July when an experienced ornithologist and wildlife photographer saw a creature matching the description of a pine marten."
EDIT
It is believed the animals have returned because large areas of forest planted after the First World War have now reached maturity, providing new habitats which had been lost."
EDIT
http://news.bbc.co.uk/1/hi/england/north_yorkshire/3953599.stm