Colonial nesting marine birds and wading birds (waterbirds) are important and conspicuous components of coastal ecosystems in the United States. They represent several orders of waterbirds that share in common the trait of typically nesting in colonies, which most likely evolved as a defense against predators. There are 23 species of colonial waterbirds nesting in the New York Bight watershed. Two species, the great blue heron (Ardea herodias) and the green-backed heron (Butorides striatus), which often nest singly, mainly in interior wetlands, are not considered here; the majority of nesting by the other species is concentrated along the coast. Also considered as part of this group 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 in the region.

New York State has surveyed colonial waterbirds on Long Island using ground counts annually since 1985. Before that, in the 1970s, aerial surveys of the Long Island colonies were conducted. The state of New Jersey surveys colonial waterbirds by helicopter about every five years, with the most recent surveys in 1985, 1989, and 1995. Both states survey certain beach-nesting birds (piping plover and least tern) annually. Federal coastal waterbird atlases were published for the Atlantic coast of the northeastern United States (Maine to Virginia) for 1977 and 1984-1985, and an atlas is now being compiled for 1994-1996. A summary of the estimated number of nesting pairs and number of colonies of waterbirds along the New York Bight coastline, including both New York and New Jersey, for 1985, 1989, and 1995 was compiled from the state surveys and is presented in

The bays and islands of the New York Bight are extremely important for nesting and foraging by long-legged waders (herons, egrets, and ibises), with a total of over 7,500 pairs recorded in the most recent (1995) surveys. In 1985, a similar number of waders in the Bight accounted for about 23% of the total Atlantic coast population from Maine to Virginia. Glossy ibis (Plegadis falcinellus), snowy egret (Egretta thula), and black-crowned night-heron (Nycticorax nycticorax) are the most common species of long-legged waders nesting in the Bight. These birds 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 (Cape May, Great Egg Harbor, and Brigantine Bay and Marsh Complex) and western Long Island (Hempstead Bays and South Oyster Bay) and in the islands in New York - New Jersey Harbor (Arthur Kill Complex and North and South Brother Islands in the Narrows) Smaller heronries also occur along the south shore bays of central and eastern Long Island (Great South Bay, Moriches Bay, and Shinnecock Bay) and in the northern coastal New Jersey bays (Great Bay and Barnegat Bay). In areas with numerous islands, the locations of heronries may shift significantly from year to year and from island to island, while there is higher site fidelity and long-term occupation in areas where there are only a few islands available for nesting. Populations of long-legged waders have been fairly stable over the past two decades, although recent declines in snowy egret (50% decline since 1989) and cattle egret (Bubulcus ibis) (70% decline since 1989) are of concern. For both of these species, especially the cattle egret, most of these declines have occurred in the Arthur Kill colonies, one of the largest colonies in the region. Double-crested cormorants (Phalacrocorax auritus) have recovered from earlier declines attributed to DDT and other pesticides and are expanding their range from the north into the Bight, occupying habitat similar to that of herons and in some instances displacing them.

The colonies of gulls and terns in the New York Bight are a significant component of the total Atlantic coast population. For example, in 1985 the New York Bight colonies of gulls and terns (excluding least tern (Sterna antillarum)) accounted for about 40% of the Atlantic coast population from Maine to Virginia. During this same period, for the common tern (Sterna hirundo) alone, the 1985 population in the Bight accounted for over 73% of the total Atlantic coast population. Gulls and terns nest on sparsely vegetated dredged material islands, rocky islands, dunes, beaches, and salt marsh islands and are widely distributed throughout the backbarrier lagoon system along the Atlantic shoreline of New Jersey and Long Island. Herring gull (Larus argentatus), for example, occurred at 146 different colonies in the Bight in 1995. 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 (Sterna dougalli) are known to travel sizable distances from their nesting areas to foraging areas, e.g., over twelve miles in Long Island Sound. American oystercatcher and black skimmer (Rhynchops niger) nest in habitats similar to those of the gulls and terns, especially on sandy islands and shorelines. Populations of all three species of gulls, as well as two species of terns (common and roseate), have declined since 1989. There were about 79,000 pairs of gulls and terns recorded in the New York Bight in 1995, significantly fewer than in 1985 (118,000) or 1989 (132,000). The most significant decline has been in common tern, which has declined 72% since 1989. This regional decline is due in part to substantial declines at some of the larger colonies such as Cedar Beach (Jones Beach Island East) on Long Island, but declines have also occurred at smaller colonies throughout the region.

In contrast to the clumped distribution of gulls, terns, and long-legged waders, beach-nesting birds are more evenly dispersed along the ocean shorelines of Long Island and New Jersey. The largest numbers of piping plover (Charadrius melodus), least tern (Sterna antillarum), and black skimmer nest on sand barrier beaches and spits near inlets. The sand spits extending into Lower New York Bay from Long Island (Breezy Point) and New Jersey (Sandy Hook) have supported some of the highest nesting concentrations for piping plover in the region. Other important nesting beaches for piping plover include Jones Beach Island West (Hempstead Bays), Jones Beach Island East (Great South Bay), and Westhampton Beach (Moriches Bay) on Long Island, and Holgate (Barnegat Bay), Little Beach Island (Brigantine Bay and Marsh Complex), and Cape May Meadows (Cape May) in New Jersey. Populations of beach-nesting birds, formerly greatly reduced due to coastal development, recreation, market-hunting, and predation, have increased over the last decade, partly in response to greatly increased management and protection, e.g., signs, fencing, predator exclosures, and patrols, of nesting beaches. Overall productivity of beach nesting birds, however, remains low due to predation and other factors. The beaches of the New York Bight supported about a quarter of the total United States Atlantic coast population of piping plover in 1995, and in 1985 the least tern population was also about a quarter of the total coastal population from Maine to Virginia.

The extensive recreational, commercial, and industrial development along the U.S. coast, with concomitant habitat modification and impacts from oil and chemical spills, dredging operations, water pollution, human disturbances, and predation, have placed waterbird colonies at increasing risk to their survival, especially in the Northeast. The most significant threats to colonial nesting waterbirds in the New York Bight include human disturbance, predation, habitat degradation, and contaminants. Recreational use of bird-nesting islands and beaches during spring and summer breeding season is detrimental to disturbance-sensitive species such as plovers, terns, and wading birds. Nesting populations of colonial waterbirds and piping plovers on sand or gravel beaches in this area are especially vulnerable during the nesting season (April to August) to human-caused disturbances such as trampling or destruction of nests from beach-walking, picnicking, boat landings, off-road vehicle use, and disturbance by pets. Predation is a major problem in waterbird colonies in the New York Bight. On beaches, mammalian predators such as foxes, skunks, raccoons, rats, dogs, and cats are a major problem; islands, although generally free from mammalian predation, may be subject to predation by gulls, crows, other birds, and insects. Degradation of nesting and foraging habitat is a major threat to both island-nesting and beach-nesting species. Attempts to stabilize and control erosion on beaches often result in a loss of natural diversity of beaches and decreased habitat suitability for nesting and feeding plovers. Increased vegetation and succession on some islands may reduce their suitability for nesting by terns and gulls. Destruction of trees from the guano of nesting and perching double-crested cormorants has reduced the suitability of many nesting islands for herons in Long Island Sound and may affect additional areas as cormorants expand to the south. Competition for nesting sites and predation by gulls results in loss of tern nesting habitat. Contaminants continue to be a major threat to waterbirds, especially those that feed at or near the top of the aquatic food chain where organochlorine pesticides and other contaminants can accumulate at high levels. Of special concern are the heronries in the Arthur Kill in New York Harbor, which occur near sites heavily contaminated by dioxin, heavy metals, and other chemicals.

Attempts should be made to eliminate all human-related disturbances to bird-nesting colonies during the critical nesting season by all available means, including posting, fencing, boat warden patrols, and public education. Further, there is a need for active habitat management and vegetation control to enhance conditions favorable to breeding bird colonies and to discourage the proliferation of gulls, other human-associated species, and natural predators. Dredged material deposition should be designed to enhance habitat on nesting islands and beaches or even to create offshore islands. Erosion control projects should be done in a way that recognizes the dynamic nature of barrier islands and natural processes such as overwash and breaching, as well as the needs of the natural communities and of fish and wildlife species that occur in the nearshore waters, on the beach and dunes, and in the backbarrier bays and marshes. Acute and chronic impacts of contaminants on colonial nesting waterbirds and their forage base require additional study, and contaminated sites that are foraging areas for waterbirds should be given a high priority for remediation. Regional declines in populations of waterbirds such as the above-noted decline in common tern should be investigated further to determine if the declines are part of natural fluctuations or whether they are related to contaminants or other threats. While the emphasis for protecting waterbirds has typically been on nesting sites, it is extremely important to better understand and protect important foraging and stopover areas as well. Because of the high turnover rate in waterbird colonies, all potential and alternate colony sites in appropriate habitat, as well as existing colonies, should be managed and protected.

References:

Andrews, R. 1990. Coastal waterbird colonies: Maine to Virginia, 1984-1985. An update of an atlas based on 1977 data, showing colony locations and species composition at both time periods, with examination of changes in regional populations. U.S. Fish and Wildlife Service, Newton Corner, MA.

Buckley, P.A. and F.G. Buckley. 1980. Population and colony-site trends of Long Island waterbirds for five years in the mid-1970s. Transactions of the Linnaean Society of New York 9:23-56.

Erwin, R.M. and C.E. Korschgen. 1979. Coastal waterbird colonies: Maine to Virginia, 1977. An atlas showing colony locations and species composition. U.S. Fish and Wildlife Service, Biological Services Program, FWS/085-79/08.

Jenkins, C.D., Jr., L.J. Niles, and J. Wessel. 1990. Survey of colonial nesting waterbirds on the Atlantic Coast of New Jersey - 1989. New Jersey State Department of Environmental Protection, Division of Fish, Game and Wildlife, Endangered and Nongame Species Program, Trenton, NJ.

Howe, M.A., R.B. Clapp, and J.S. Weske. 1978. Marine and coastal birds. Marine Ecosystems Analysis Program New York Bight Atlas Monograph 31. New York Sea Grant Institute, Albany, NY.

Litwin, T.S., A. Ducey-Ortiz, R.A. Lent, and C.Liebelt. 1993. 1990-1991 Long Island colonial waterbird and piping plover survey. Conducted by New York State Department of Environmental Conservation in cooperation with the Seatuck Research Program.

New Jersey State Department of Environmental Protection. 1996. Unpublished 1995 colonial waterbird survey data. Endangered and Nongame Species Program, Trenton, NJ.

New York State Department of Environmental Conservation. 1996. 1995 Long Island colonial waterbird and piping plover survey. Division of Fish and Wildlife, Region 1, Stony Brook, NY.

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