The Allegheny National Forest is continuing its effort to reintroduce fishers to the forested areas of northwestern Pennsylvania.
Nine of the weasel-like animals, including eight females, were released Monday along Upper Sheriff Run, a tributary to the Tionesta Creek.
Allegheny National Forest wildlife biologist Brad Nelson said, "Last year we unexpectedly trapped more males than anticipated, so eight females released this winter will help balance the ratio and hopefully increase the odds of reproductive success."
Fishers are a sleek, blackish-brown animal, slightly larger than a woodchuck. They were common in Pennsylvania's forests a century ago, but disappeared about 1900 mainly because of unregulated trapping and loss of forest habitats.
Penn State University's Wildlife and Fisheries science program now says the habitat exists to support a limited number of fishers.
Mostly nocturnal and seldom seen, the animals climb trees, and eat mice and other small mammals as well as fruits and vegetation.
The reintroduction program began last winter when 38 fishers were released, including 11 females. Four were eventually found dead, the victims of predators or collisions with cars. The remaining 34 are thought to be doing well.
The nine newly released fishers were fitted with radio collars to help researchers track their movements.