Mamacoke Island is an undeveloped island in the Thames River. The island is covered with hardwood forest, and it partially encloses two small coves. It is immediately south of a larger cove, Smith Cove. The island is owned and managed as a natural area by the Connecticut College Arboretum. The coves are public waterways bordered by land owned by the Connecticut College Arboretum, a railroad and (on Smith Cove) numerous homeowners.

Ornithological Summary

This complex of coves provides the best habitat for winter-resident waterfowl on the Thames River. Ducks concentrate in this area throughout the winter, but they are most abundant when lakes, reservoirs, and small rivers freeze. The tidal, estuarine waters on the Thames River usually remain open, and the shallow coves provide good feeding areas during these critical periods. The number of ducks in this complex of coves can reach 500-1000. This count does not include the large number of Canada Geese and Mute Swans. Notable species are Canvasback (as many as 600) and Hooded Merganser (as many as 176). Two species that are rare in Connecticut, the Redhead and Lesser Scaup, are regular in these coves during the winter. During the summer, these coves and the Mamacoke tidal marsh provide feeding areas for Ospreys, Great Egrets, Snowy Egrets, Little Blue Herons and Black-crowned Night-Herons.

Conservation Issues

A major marina development has been proposed for Smith Cove. This would affect one of the primary feeding areas for ducks. Water pollution is a continuing threat on the Thames River.


Connecticut College


Primary: River/Stream. Secondary: Brackish tidal marsh, estuary, shrub/scrub.

Land Use

Primary: Nature and wildlife conservation, hunting/fishing, research, education. Secondary: Suburban/residential.

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