MONTPELIER (AP) -- The population of the American marten appears to be growing in Vermont based on the frequency of sightings and evidence of reproduction, the state Fish and Wildlife Department said.

The small carnivore in the weasel family became extinct in Vermont in the early 1900s. But evidence collected over the past 20 years shows that two small populations of marten have become established in the state.

One population in the southern Green Mountains likely originated from the state’s release of 115 marten from 1989 to 1991 as part of a reintroduction effort, said Chris Bernier, furbearer biologist with the state Department of Fish and Wildlife. The other population, in the Northeast Kingdom, may have come from New Hampshire and Canada, he said.

Recent sightings show the total population is expanding, despite hurdles such as fragmentation of Vermont’s forests; competition from the abundant fisher, another member of the weasel family; and milder winters, he said.

"All of this evidence leads us to believe that there may be more marten out there than we had previously thought," Bernier said.

Studies in the 1990s did not show signs of the animals so researchers believed that the reintroduction efforts had failed, the department said. But it now appears that some marten populations may have become established after the release.

Wildlife biologists so far have examined 17 marten, 15 of which were juveniles, which shows that they are reproducing and possibly expanding in Vermont, Bernier said.

"Marten depend on large blocks of unfragmented forests. Their return signals that land conservation efforts are paying off for marten and other rare species in Vermont and that these large unfragmented forests are being properly managed by biologists and foresters," he said.