 Over 400 species of birds have been found in Pennsylvania, including 186 that breed in the state.Birds such as ospreys, hawks, owls, nightjars, and bald eagles have returned to the park and state forest, and saw-whet owls have been studied in the park.Some animals which had been locally extinct have also returned or been reintroduced to the area, including white-tailed deer, elk, fishers (a type of weasel), and otters.