Snowy egret
 
 

Cattle egret

- general -
Colonial nesting marine birds and wading birds (waterbirds) share the characteristic of typically nesting in colonies. They represent several orders of waterbirds, e.g., cormorants, herons, egrets, ibises, gulls, terns, and skimmers and are important and conspicuous components of coastal ecosystems in the United States.  These colonial nesting birds are often concentrated in small areas and are therefore vulnerable to disturbance, predation, habitat destruction, and other events that could eliminate a large number of birds at one time.  Several waterbird species feed near the top of the estuarine food chain and are therefore good indicators of an estuary’s health. 
 

- threats -
The most significant threats to colonial nesting waterbirds include human disturbance, habitat degradation, contaminants, and predation.  Extensive recreational, commercial, and industrial development along the U.S. coast have caused the loss of a great deal of waterbird habitat.  This, coupled with impacts from dredging, water pollution, human disturbances, and predation (of eggs by dogs, cats, raccoons, foxes) have increasing threated the survival of waterbird colonies, especially in the Northeast. 
 

- details -
There are 23 species of waterbirds nesting in the Southern New England - New York Bight project area.  In addition, there are two species of shorebirds, the piping plover (Charadrius melodus) and the American oystercatcher (Haematopus palliatus), which generally do not nest in distinct colonies but do share the same habitats as many of the colonial nesters and are species of concern.

Long-legged waders (herons, egrets, and ibises) prefer to nest in large colonies in shrubs or trees on salt marsh, dredged material, or rocky islands.  They are thus most common where there is a prevalence of vegetated islands, especially the salt marsh and dredged material islands in the sounds and bays of southern New Jersey, southwestern Long Island, the New York - New Jersey Harbor, Long Island Sound, Narragansett Bay, and Buzzards Bay.  In areas with numerous islands, the locations of heronries may shift significantly from year to year and from island to island. 

Of the eight species of waders that nest in the project area, glossy ibis (Plegadis falcinellus), snowy egret (Egretta thula), and black-crowned night-heron (Nycticorax nycticorax) are the most common.  Eleven species of gulls, skimmers, and terns such as common tern (Sterna hirundo) and herring gull (Larus argentatus) nest on sparsely vegetated dredged material islands, rocky islands, dunes, beaches, and salt marsh islands.  These colonies are widely distributed throughout the backbarrier lagoon system along the Atlantic shoreline of the project area and on islands in the large estuaries.   Colonies of the federally endangered roseate tern (Sterna dougalli) account for over 95% of the northeastern breeding population of this species. 

As with the heronries, there is a great deal of year-to-year variability in the location of gull and tern colonies.  Although some gull and tern species nest near their primary foraging areas, roseate terns are known to travel sizable distances, e.g., over twelve miles in Long Island Sound, from their nesting areas to foraging areas.  In contrast to the clumped distribution of gulls, terns, and long-legged waders, beach-nesting birds are more evenly dispersed along the region’s ocean shorelines. 

Waterbird colonies are surveyed by states on a regular basis, and recent coastwide data collections are being coordinated by the Patuxent Wildlife Research Center.