With the booming voice of a former University of Washington linebacker -- which he used to be -- Rep. Norm Dicks (D-Wash.) rose to the House floor to defend a small chubby seabird. Dicks, an 18-term congressman who will retire at the end of this session, warned the House in the summer of 1996 that Congress had no business exempting a California timber company from the Endangered Species Act. As Dicks enters the final months of his 36-year career in Congress, some admirers are wondering who will carry on his work on wildlife, watersheds and the climate, and whether they will share the same connection to public lands.