Wellfleet Bay Wildlife Sanctuary in Wellfleet, Massachusetts, protects 1,183 acres along Wellfleet Harbor on Cape Cod Bay and reflects a layered history from Nauset homeland to farmland, research station, and conservation area. Oliver L. Austin established the Austin Ornithological Research Center here in 1929, and after his death in 1957 the Massachusetts Audubon Society bought its 366 acres and expanded the preserve by acquiring more nearby land. Today the sanctuary offers trails, a nature center, campground, and educational programs across varied coastal habitats, while ongoing conservation work includes protecting diamondback terrapin nests. It is also a major Cape Cod birding site, with at least 309 species recorded.