The discovery comes a year after kits were filmed on Dartmoor, where the project released 15 pine martens in 2024.
The reintroductions represented the first attempt to re-establish a sustainable breeding population of the tree-climbing members of the weasel family in the South West since they were hunted to extinction more than a century ago.
Conservationists said the pine martens have proved to be highly mobile, shy of people and difficult to see.
Ali North, field officer at the project for Exmoor, added: “We were incredibly excited to finally see kits after so many months of intensive monitoring.
“This has been a community effort with local people helping us in a series of key tasks ranging from building pine marten den boxes to installing and regularly checking remote cameras.”
Despite the breeding success of pine martens on Exmoor and Dartmoor, the project members warned that the animal’s comeback to the region is still in its early, fragile stages.
