Naturalist Peter Alden, author of the Audubon Guide to New England, will lead a 2.5-hour walk focusing on birds and plants on the Bruce Freeman Rail Trail from West Concord toward White Pond. Meet at the beginning of the Rail Trail in West Concord (Rt. 62). Pre-registration appreciated. For more Riverfest events, visit https://www.sudbury-assabet-concord.org/riverfest-2023.