The Parker River National Wildlife Refuge is offering visitors a behind-the-scenes tour. Weather permitting, tours will be held at 1 p.m. Thursday, 1 p.m. next Sunday, and 9:30 a.m. on Wednesday, Nov. 28. Participants will board a van and view the refuge through the lenses of the cultural history of Plum Island and the Great Marsh, native wildlife and their habitats, and the role of refuge management in the conservation of these natural resources. Participants will be driven along areas of the refuge otherwise closed to the public. This two-hour program is guided by a wildlife refuge ranger. It is most appropriate for older teenagers and adults. Binoculars and/or a camera are recommended, but not required. Each tour is limited to 10 participants. Registration must be made in advance by calling 978-465-5753. No more than four individuals may be registered from one party at one time.