Waste goes in and pride comes out in Arcata’s pioneering wastewater treatment plant, also known as the Arcata Marsh and Wildlife Sanctuary, a 307-acre expanse with freshwater marshes, salt marsh, tidal sloughs, grassy uplands, mudflats, brackish marsh and 5 miles of walking and biking paths. Located at the north end of Humboldt Bay, the sanctuary is situated along the Pacific Flyway, a major migratory route for thousands of birds that breed in the far north and winter in California, Mexico and Central and South America. It has probably the most populated bird coastal site between Bodega Harbor and Washington, with literally thousands of birding visitors annually and organized bird walks held at least weekly on the year-round viewing deck. Start at the Humboldt Redwoods Interpretive Center, which explains the low tech wonder and explores the many birds that reside there full or part time.