 That population has been successful and by 2010 there were up to 105 migrating birds established in the eastern United States for the first time in over 100 years.Other threatened or rare species at the site include the Karner blue butterfly, massasauga rattlesnake, Blanding's turtle, and wolf packs.In most years the refuge is also an important stopover for migratory waterfowl on the Mississippi Flyway.