The largest of the Refuge's islands, the 135-acre Choate Island (formerly Hog Island) supports myriad birds and mammals including deer, fisher, coyote, and otter. The spruce forest planted in the early 20th century attracts golden crown kinglets and sharp-shinned hawks, while Choate Island's grasslands provide critical habitat for bobolinks and Savannah sparrows. Gulls, sanderlings, and sandpipers feed along the Island's shore.
Well before the arrival of European settlers, the Agawam tribe of Native Americans established semi-permanent agricultural villages here, harvesting shellfish in and around the islands in the warmer months. During the 18th and 19th centuries, Choate Island and Long Island, connected by a causeway, comprised a prosperous farming community. The c.1778 Proctor Barn on Long Island and the c.1725–40 Choate family homestead stand as reminders of this agricultural past.
The Refuge was established in 1974 as a gift of Miné S. Crane in memory of her husband, Cornelius Crane; both are buried at the summit of Choate Island.