Naturalists, kayakers and other volunteers are needed to look for as many birds, plants, insects, mammals and fungi as possible during the 24-hour Bioblitz 2011 at the Washington Park Arboretum. The event starts at 3 p.m. Friday, Oct. 21, and ends at 3 p.m. Saturday, Oct. 22. Volunteer by sending e-mail or calling 206-543-8801.