Nature Walk focusing on butterfly identification, 10 a.m. Meet at the Lock 70 parking area (Oldtown). Walk will head upstream to the Alum Hill Deep Cut and back. Bring water. Optional equipment: binoculars and your favorite butterfly ID book. For more information, contact Paul Petkus at firstname.lastname@example.org or 773-450-6039 (text). Walk will be canceled in case of inclement weather.