Go down to the woods today and you may get a rare surprise

The search is being renewed this year for England's most elusive and enigmatic wild mammal, the pine marten.

The tree-dwelling carnivore, a larger relative of stoats and weasels, was thought by some to be extinct in England, although not in Scotland.

Yet research over several years by the Vincent Wildlife Trust indicates there are pine marten populations in England's more remote corners, as well as in parts of Wales, where the animal was also thought to be extinct.

Although there have been numerous reported sightings, accurate photographic evidence is still lacking, but last year the research effort was crowned with biological success when a dropping was found by a member of the Northumberland Wildlife Trust in Kidland Forest, which DNA analysis showed unequivocally came from a female pine marten. Now the search for the animals in the forest is to be stepped up, with five special nesting boxes being erected.

"The discovery of droppings near Kidland was stunning news, but we are still very much in the dark about the pine marten's status," said Tom Dearnley, the Forestry Commission ecologist for North-east England.

"If we can entice an animal to use one of the boxes, not only will it teach us more about the pine marten population in England, but it will also provide both a chance to study its behaviour and a place to rear young." A native mammal of Britain and Ireland, Martes martes is also related to mink, polecat, otter and badger. The animal sports a coat of rich brown fur which contrasts with a creamy-yellow "bib" on the throat and chest. Adults are similar in size to a small or medium-sized domestic cat, with males about a third larger than females.

The animal probably arrived in Britain and Ireland soon after the end of the last Ice Age, about 9,500 years ago. It would have been most numerous when Britain and Ireland had greater tree cover and it has been suggested that 6,500 years ago pine martens were the second most common carnivore in Britain. However, it had been persecuted to extinction throughout much of Britain by the early part of the 20th century, with a solid population surviving only in Scotland. There, studies show that the animal is now recovering strongly, but the same is not happening with populations in England and Wales and the Vincent Wildlife Trust aims to find out why.

The research has now identified three English pine marten "hotspots" – the Lake District, the North York Moors and Northumberland, with a less important area in the Peak District in Staffordshire and four key areas in Wales, of which the two most important are Snowdonia and Camarthenshire.