The first pine martens to be reintroduced to England have had kits, marking a milestone in efforts to boost their recovery, conservationists said.

The native carnivores all but vanished from England in the face of extensive hunting and loss of their woodland homes over the past two centuries, and were pushed to a stronghold in the north-west Highlands of Scotland.

Though the species has made a comeback in Scotland, they remain very rare in England, prompting the first formal reintroduction scheme in the Forest of Dean, Gloucester, to boost the recovery of the mammals in the country.

The scheme, led by Gloucestershire Wildlife Trust and Forestry England – with support from Vincent Wildlife Trust, the Woodland Trust and Forest Research, has marked a success with newly-released females giving birth to young.

The first 18 animals were translocated from Scotland to Gloucestershire in September 2019.

Radio tracking and trail camera monitoring has revealed that at least three females have given birth and have young.

Members of the public are unlikely to see the solitary, elusive animals, but the footage reveals them making themselves at home in the forest.

The fact that some females have given birth suggests the conditions in the forest are as good as we had hoped

Pine martens do not necessarily breed every year, which is part of the reason for their slow recovery from Scotland back to England and Wales, and the arrival of kits shows conditions in the forest suit them, the experts said.

Dr Cat McNicol, Gloucestershire Wildlife Trust’s conservation projects manager, said: “This is hugely reassuring for us and a major success factor for the project.

“The fact that some females have given birth suggests the conditions in the forest are as good as we had hoped.

“There seems to have been plenty of food available for them through winter and there are lots of great denning sites for the females to give birth and raise kits in, such as old beech trees full of hollows and mature conifers with cracks and cavities out of reach.”

The animals mate in the summer, but delay their pregnancy until spring when the conditions are right for them.

Most pine martens give birth to two or three kits, who start to be weaned at about six weeks onto solid food such as voles, mice and small birds that the females bring back to the dens to feed them.

As they get older, they start to practise climbing, though they are clumsy to start with and can fall out of their dens, so looking after them and hunting for food means it is a busy time for the mothers, the experts said.

The three-year reintroduction project, which follows a scheme to bring them back to Wales, aims to bring up to 60 pine martens to the Forest of Dean.

Rebecca Wilson, planning and environment manager for Forestry England, said: “The hope is that over the next two years, more pine martens will be released into the Forest and that a population will establish there.

“This population will then spread and link up with recently reintroduced Welsh pine martens, creating a new stronghold for the species and ensuring its survival.”