Ram Island supports 40 percent of the Massachusetts population of Roseate Tern (20 percent of the continental population); 20 percent of the Massachusetts population of Common Tern; and up to 12 nesting pairs of Willets (since 1995) and 5 pairs of American Oystercatchers (since 1995). This IBA is one of a small number of islands suitable for seabird nesting in southern Massachusetts (Buzzards Bay). A long-term research program with ongoing intensive studies of terns is continuing there.

Ram Island, located 0.8 km southeast of Mattapoisett Neck, Mattapoisett, is composed of eroded glacial till surrounded by scattered boulders. There is a tidal pond in the center with a small area of low-grade salt marsh and a storm beach of gravel and shell. Other substrates include cobbles, boulders, and soil. There is a cover of herbaceous vegetation growing in some areas to over 6.5 feet tall in summer and some areas with dense Beach Rose. The island is exposed to wave action from the south and is washed over in hurricanes and occasional winter storms. Common and Roseate terns have been known to breed on the island since the 1930s.

Ram Island is subject to predation by Great Horned Owls and Great Black-backed Gulls, which take fledgling terns. The island has steadily been eroded and lost elevation over the past 30 years, resulting in a steady loss of available nesting areas for terns. It is impractical to reverse this process because of the tidal pond and salt marsh, and the lack of structures that would justify actions that would alter wetland designation. Tern populations were damaged in the 1970s to 1990s by PCBs released into New Bedford Harbor, so they are eligible for restoration under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).