The distance from the mainland decreases to between 100 and 200 feet during low tide as expansive sandbars and tidal flats are exposed.

The island is separated from the mainland by exceptionally shallow water during low tide, such that it can easily be accessed on foot.

Menunketesuck Island is part of the Salt Meadow Unit of the Stewart B. McKinney National Wildlife Refuge and was designated by the National Audubon Society as an "Important Bird Area", as it hosts populations of water birds including the least tern, American oystercatcher, great egret, glossy ibis, Black-crowned night heron and various gull species.

The long-legged wading birds, such as egrets and ibises, use the island's trees to nest and raise their young.

The surrounding waters, mudflats and nearby marshes constitute a tremendous ecosystem for birds like these to find food, shelter and space.