Boston Harbor Islands National Recreation Area - Animals

The diversity of upland and marine habitats provides good nesting and feeding opportunities for a number of bird species. Field surveys have identified more than 100 bird species including gulls, terns, herons, ducks, geese, hawks, plovers, sandpipers, doves, owls, woodpeckers, and perching birds. During migration, large numbers of shorebirds utilize the mudflats and salt marshes around the harbor, while transient hawks and songbirds regularly make use of the more remote islands, or those with suitable habitat. In late fall and winter, great flocks of waterfowl gather in harbor waters.

A few species of terrestrial mammals, including exotic species, occur throughout the islands, such as cottontail rabbits, raccoons, skunks, gray squirrels, mice, muskrats, voles, and Norway rats. Some species have been known to devastate populations of small vertebrates and nesting birds. Although formal surveys are in initial stages, Eastern garter snake, Northern brown snake, and Eastern smooth green snake are known to occur on the islands. Wetland and Aquatic Marine Animals The Boston Harbor Islands provide shelter and food-rich habitats for marine birds, mammals, fishes and invertebrates, as well as nurseries for their young.

Much of the Gulf of Maine fauna can be found in Boston Harbor, especially around the Brewsters. Lobsters, crabs, and clams inhabit submerged portions of the islands. Mussels and barnacles cling to the intertidal zone. Jellyfish live in the surrounding waters. Several species of fish, including striped bass, bluefish, and winter flounder, live in waters surrounding the islands. Little Brewster, Nixes Mate, Shag Rocks, and other islands characterized by bedrock outcroppings contain rocky intertidal communities of rockweed and barnacles. Harbor seals haul out on some of the outer islands. Because their feeding grounds or migratory routes are nearby, humpback, fin, minke, and North Atlantic right whales and white-sided and striped dolphins are potential, though rare, visitors, as are harbor porpoises.