Wetland conservation : hearings before the Subcommittee on Environmental Pollution of the Committee on Environment and Public Works, United States Senate, Ninety-eighth Congress, first session, on S. 978 a bill to extend until October 1, 1993, the authorization for appropriations to the Migratory Bird Conservation Fund, and for other purposes ; and S. 1329 a bill to extend until October 1, 1993, the authority for appropriations to promote the conservation of migratory waterfowl and to offset or prevent the serious loss of wetlands and other essential habitat, and for other purposes, July 12, 1983--Washington, D.C. ; August 10, 1983--Aberdeen, S. Dak