SLATY-BACKED GULL: Will County (North) – Discovered by Andrew Aldrich on 26-Jan-2016, a Slaty-backed Gull is still present on the property of ASIP: Local 150 at 19800 W. Arsenal Rd. Birders have had success viewing the gull in the morning prior to 9am resting on the frozen pond of the property during the work week while the nearby landfill is open.