|Mass.Gov Home Page||State Agencies||State A-Z Topic List|
The Birds of the Harbor Islands
By Christopher Klein, author Discovering the Boston Harbor Islands
Printer-friendly PDF (364 KB)
The Boston Harbor Islands is considered an Important Bird Area by organizations such as the Massachusetts Audubon Society. A variety of habitats (marine, rock cliff, beach, salt marsh, and forest) support more than 100 species. Many species of waterbirds nest on the islands. It is common to see large colonies of Double-crested Cormorants, Herring Gulls, Great Black-backed Gulls, and Common Eiders on the rocky shores and scrub habitats of the outer islands. A colony of Least Terns, a state-listed species [of special concern (i.e., could become threatened)] occurs on Rainsford Island.
Black-crowned Night-Herons, Snowy Egrets, Great Egrets, and to a lesser extent, Glossy Ibis, breed among the islands as well. These wading birds nest in the trees along the coastline. Sarah Island has the largest wading bird colony in the harbor. Recently, American Oystercatchers were recorded on Slate, Lovells, and Snake Islands.
As suspected, smaller islands have less diverse populations of breeding landbirds than larger islands. It is believed that Peddocks Island has as many as 34 breeding species. Landbirds such as Song Sparrows, Red-winged Blackbirds, and Yellow Warblers are common to the area. The more widespread Savannah Sparrow can be found nesting on the restored grasslands of Spectacle Island.
Migrating shorebirds are most commonly found on Snake, Rainsford, and Great Brewster Islands from July through August. In the past, sightings have included Black-bellied Plovers, Purple Sandpipers, and Ruddy Turnstones.
Park managers use the size of the breeding bird populations and the number of nests, eggs, and chicks to gauge the environmental health of the park. Breeding season occurs from May through the end of July. The public is asked to respect this delicate stage in the life cycle and not to disturb the colonies while they are at work.
Bird lovers should check out eBird, a database for birdwatchers. Contributing your observations will help scientists understand species distribution and movement patterns in Massachusetts and across the continent. www.ebird.org.
Photos: Christopher Klein