CHICAGO -- Volunteers were out doing their part to clean up along the North Branch of the Chicago River Saturday morning.Community members collected trash near Horner Park Nature Path near Montrose and the River.The group says it's cleaning up pollution that clutters the habitat for aquatic animals.The clean-up was planned after discovering a mallard duck entangled in a plastic six-pack ring.That duck has since been named Ringo. Rescuers have been unable to grab and free Ringo.The Shedd Aquarium, which donated supplies to the group, says it's dedicated to reducing plastic pollution to protect wildlife.