The Harbor Heron Islands
Great and Snowy Egrets in New York Harbor. Photo: Yigal Gelb
In the waters that divide New York City’s five boroughs, hemmed in by development and crisscrossed by bridges, ferries, and tunnels, lies an overlooked, scattered wilderness: the islands of the Harbor Herons. Wild to an extent that seems near impossible in the midst of one of the world’ s largest cities, our “urban archipelago” provides nesting grounds for 10 species of long-legged wading birds, along with cormorants, gulls, terns, ducks, geese, Osprey, and many songbirds. Both the islands and the birds that nest upon them are now protected from harm, thanks to over a century’s worth of conservation work. NYC Audubon is dedicated to ensuring the islands remain a safe refuge for waterbirds in New York City.
Totaling over 20 islands in all, the Harbor Heron islands have diverse and fascinating histories: Some are natural islands, like the Brother Islands of the Bronx. This pair of islands was once quite developed, hosting quarantine hospitals in the late 19th and early 20th centuries. (North Brother Island served as home for “Typhoid Mary” for over 25 years.) Hoffman and Swinburne Islands, in the lower harbor, were also used to quarantine the sick. These two islands are artificial, however, created to receive ill immigrants in the late 1800s. Other islands, including several in Jamaica Bay, are built-up versions of their former selves: low-lying patches of tidal salt marsh that were raised by the addition of dredge spoils from the harbor, creating land that is not regularly flooded.
Despite their varied origins, however, the islands have something in common: they are only reachable by water, and so neither people nor mammalian predators have easy access to them. This relative isolation has allowed them to become havens for waterbirds over the past 50 years, after the birds were absent for many decades. The birds’ absence, and their return, is a story in itself.
The Harbor Heron Islands (blue dots). These waterbird nesting colonies have been monitored by NYC Audubon researchers since 1982. Graphic: NYC Audubon. Click here to enlarge.
Harbor Herons History: Long-Absent Waders Return to NYC
The natural bits of land among what we now call the Harbor Heron islands must have provided safe nesting grounds for waterbirds, centuries ago. We don’t have records of nesting from that time. But we do know that by the late 19th century, Great and Snowy Egrets, along with many other waterbirds, were nearly extirpated in North America due to the demand for the birds’ ornate breeding plumes, in fashion as an adornment of ladies’ hats.
Egrets and all other migratory birds were eventually safeguarded thanks to the determined advocacy of early Audubon Society founders. And under the protection of the 1918 Federal Migratory Bird Treaty Act, and seeded by surviving southern colonies, herons slowly returned to former habitat along the East Coast during the first half of the twentieth century.
By 1950, the wader population had begun to spill north—and by 1960, Snowy Egrets were found nesting as far north as the Isles of Shoals off the coast of New Hampshire. At first, however, the recovering birds bypassed the Hudson River estuary—possibly because our harbor’s water, heavily burdened with household and industrial waste, supported little or no food for wading birds. In 1972, the Clean Water Act offered hope for revitalization of New York Harbor.
In 1974, local birders were astonished to find that a few wading birds had established a colony on Shooters Island in the Kill Van Kull, along the north shore of Staten Island. By 1978, the colony had spread to Prall’s Island, off of Staten Island’s western shore—and soon after to the nearby Isle of Meadows.
Mayor Edward I. Koch signs a management agreement for Prall’s Island with NYC Parks/NYC Audubon on Thursday, February 21, 1985. Pictured (left to right): past Board Member Peggy Kane, past Board President and Vice President Albert F. Appleton, NYC Parks Commissioner Henry Stern, past Board President and Vice President Bette Brookshire-McGrath, Mayor Edward Koch, and Wally Popolizio. Photo: Mitch Heiberg
NYC Audubon Achieves Protection for the New Colonies
The fledgling New York City Audubon Society, founded in 1979, soon came to focus its attention on these new and growing wader colonies—which included good numbers of Great, Snowy, and Cattle Egrets, Black-crowned Night-Heron, and Glossy Ibis, along with smaller numbers of Little Blue Heron, Green Heron, and Yellow-crowned Night-Heron. NYC Audubon advocated and won protection for the first colonies, which soon became known as the Harbor Heron Islands.
Responsibility for Prall’s Island, which had been privately owned, was transferred to the Department of Parks and Recreation, and in February of 1985, NYC Parks and NYC Audubon signed a 30-year contract assigning management and responsibility for Prall’s Island to NYC Audubon, officiated by Mayor Ed Koch. Shooter’s Island was assigned to NYC Parks in 1994 as a bird sanctuary. Together with Isle of Meadows, now a “Forever Wild” preserve, these three islands are considered part of the NYC Parks “Harbor Herons Wildlife Refuge.” Though NYC Audubon no longer manages these islands, we have continued to conduct our annual Nesting Survey of the Harbor Heron Islands, first conducted in 1982 and carried out annually since 1985.
Conservation Research—and an Environmental Disaster
In February of 1990, The Trust for Public Land, working closely with NYC Audubon, released a comprehensive study of land adjacent to the Staten Island colonies. The study, entitled The Harbor Herons Report, A Strategy for Preserving a Unique Wildlife Habitat and Wetlands Resource in Northwestern Staten Island, identified ownership of land parcels and the ecological significance of each piece, and laid out a program to protect the colonies and the resources.
The study was completed at an opportune time: a major oil spill at the Exxon Bayway Refinery, a mile north of Prall’s Island, soaked the salt marshes and beaches around the island with much of the 560,000 gallons of oil spilled on the night of January 1, 1990.
Fallout from the 1990 spill was extensive. Exxon Bayway modified its facilities and procedures to reduce its program of activities to ensure safe movement of vessels in the harbor. Money from a settlement (among Exxon and the several local, state, and the federal governments) and fines were used to purchase land in the areas identified in the Trust for Public Land/NYC Audubon Harbor Herons Report and to restore damaged habitat, including the banks of affected salt marshes.
North Brother Island (up top) and South Brother Island. Photo: NYC Audubon
The Harbor Herons Expand: The Brother Islands
Possibly as a result of habitat changes and contamination from the 1990 spill, wading birds abandoned their pioneer nesting colonies off of Staten Island northern and western shore over the next decade. However, the birds did not abandon the harbor: Instead, they shifted to several sets of islands across New York City. North and South Brother Islands, where the East River meets Long Island Sound, were among the next islands colonized. In 2007, NYC Audubon saw the culmination of years of work with local and federal officials and community and conservation organizations to preserve South Brother Island, then the last privately owned island in New York City.
In 2002, the Trust for Public Land managed a $2 million sale of the island to The Point Community Development Corporation and the Wildlife Conservation Society, thanks to federal funding secured by Congressman José Serrano, who at that time had worked to fund over $198 million in projects for the Coastal and Estuarine Land Conservation Program. In 2007, the island was transferred to the NYC Parks; with its sister island, North Brother, it is a Forever Wild preserve.
Yellow-crowned Night-Heron Nestlings. Photo: Kenneth Cole Schneider/CC BY-NC-ND 2.0
Ongoing Conservation and Monitoring Research
Drawing on more than 20 years of research, in 2010 NYC Audubon collaborated with a broad range of government, non-governmental, and academic institutions to develop and release The Harbor Herons Conservation Plan. This plan to protect and support waterbird populations in the harbor is part of the U.S. Environmental Protection Agency’s Conservation and Management Plan for New York/New Jersey Harbor Estuary.
Today, NYC Audubon continues to monitor 20 nesting islands in the harbor as part of our 35-year-old Harbor Herons survey project. Since the first pioneer colonies were found off Staten Island, wading birds have established stable breeding presences in Jamaica Bay as well as on islands in lower harbor, the East River, and Long Island Sound. The largest active colonies today include South Brother Island, Hoffman Island (off the eastern side of Staten Island), and several islands in Jamaica Bay. Learn more about NYC Audubon's Harbor Herons conservation project and view nesting survey results.