Delaware Bay Estuary Project
Northeast Region

Delaware Bay Focus Area

black duck

Black Duck in Delaware Bay Area

The beaches, dunes, wetlands, and forests of the Delaware Bayshores are important to more than 100 species of migratory and nesting birds, including waterfowl, raptors, shorebirds, and songbirds. For many neotropical migratory birds, the Bayshores region (see also the Twin Capes Focus Area) is a critical stop-over site. In the spring, horseshoe crabs (Limulus polyphemus) travel toward the shore from their winter habitat along the continental shelf to lay their eggs on the beach during high tide. In concert with this extraordinary event is the arrival of the shorebirds from South America. 

Delaware Bay hosts the largest spawning population of horseshoe crabs in the world and the second largest population of migrating shorebirds in North America.  Over eighty percent of the Western Hemisphere’s population of red knot (Calidris canutus rufa) depends upon horseshoe crab eggs to double their weight in less than two weeks before flying to the Arctic to nest.  These migrants depend on the eggs of spawning horseshoe crabs for a major portion of their diets (50 to 90 percent) each spring before migrating from the Delaware Bay beaches to Arctic nesting grounds.  Delaware Bay is designated within the Western Hemisphere Shorebird Reserve Network as having the highest reserve status.   In addition to providing the principal food source for migratory birds in Delaware Bay, horseshoe crabs comprise the main diet of juvenile loggerhead turtles. 

Great blue heron
Great Blue Heron

The largest heron rookery north of Florida, Pea Patch Island Heronry contains about 15,000 birds, composed of nine different species.  The birds forage in the surrounding wetlands, at least as far as 25 kilometers away.  The populations of some species are declining.  A Special Area Management Plan has been developed to help conserve this resource.  High quality wetlands provide important foraging habitat for these birds.

The wetlands surrounding Delaware Bay have been recognized as having international significance by the Ramsar Convention on Wetlands.   The Delaware estuary serves as a spring staging area for as many as 200,000 snow geese.  The estuary annually winters approximately fifteen species of waterfowl which comprise a population of nearly 500,000 birds.  The bay area supports federal and state endangered and threatened species including: bald eagle, peregrine falcon, piping plover, pied-billed grebe, short-eared owl, shortnose sturgeon, and five species of sea turtles.  The Delaware Bay region is a critical migration and wintering area for American black duck in the Atlantic Flyway.

Delaware Bay Focus Area Fact Sheet

Last updated: March 30, 2010

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