_{NYC Bird Alliance scientists predict Black-crowned Night Heron, pictured here with chicks, will disappear from our harbor in the next 10 years without conservation action. Photo: Susan Hodgson}

This article appears in the spring 2025 issue of The Urban Bird Call.

Tod Winston, Urban Biodiversity Specialist | February 25, 2025

As a birding guide and a former leader of NYC Bird Alliance’s annual Harbor Herons Nesting Survey, I know how the City’s charismatic wading birds can inspire New Yorkers. The Black-crowned Night Heron is one of our most exciting residents, often seen hunting along the City’s shores. Of the 10 species of long-legged wading birds that nest on the islands in New York’s harbor, the Black-crowned Night Heron has long been the most abundant. Sadly, however, NYC Bird Alliance’s scientists have determined that the species is in critical decline here and across the Northeast: According to recent analysis of our over four decades of research data, it may disappear entirely from the harbor as soon as 2035. Ten years from now.

Long-legged wading birds, including herons, egrets, and ibises, have not always been as common in our harbor as they are today. At the turn of the 19th century, these birds were hunted nearly to extinction for their beautiful breeding plumes, used to decorate ladies’ hats. The first Audubon Society formed in Massachusetts to stop that slaughter, leading to the Migratory Bird Treaty Act of 1918. Though this probably saved birds like Great and Snowy Egrets from extinction, a diverse population of wading birds didn’t return to nest in the harbor for decades.

“This handsome yet often overlooked bird has been key to the success story of herons returning to the New York-New Jersey Harbor,” says Dr. Susan Elbin, NYC Bird Alliance’s former director of conservation and science who oversaw the surveys from 2007 to 2019. The growth in the mid-1970s of breeding colonies on small islands near Staten Island followed passage of another landmark conservation law, the Clean Water Act of 1972. “Their population trends serve as key indicators of ecosystem health,” Susan continues. “And now, with their continuing decline, the birds are telling us we need to take action to protect them and their habitat before it is too late.”

NYC Bird Alliance (then NYC Audubon) began annual surveys of these birds in 1985, building decades of systematic population data. Though these surveys found that the birds’ presence around the harbor might shift, their total number continued to climb into the early 1990s. 

Analysis of our 40 years of data, however, revealed a significant decline in the total Harbor Herons population since 2000—notably among Black-crowned Night Herons, and to a similiar extent, Glossy Ibises. (While also concerning, the decline in Glossy Ibis, a less abundant species here, is thought to be a natural contraction of its recently expanded range.) Further support is needed to research why Black-crowned Night Heron numbers have fallen. Likely possibilities include chemical pollution, predation, competition, declines in prey species, habitat loss, and climate change. But determining the actual causes will need more focused studies—requiring resources that typically come from major research universities or state or federal wildlife agencies. 

“Black-crowned Night Herons are in serious decline—but if we act now, we can help them recover,” says Dr. Dustin Partridge, director of conservation and science. A first step, according to him, would be the establishment of Threatened or Endangered status for them in New York State to prevent further direct anthropogenic harm. The imminent scientific journal publication of NYC Bird Alliance’s research findings, anchored by the data analysis performed by Harbor Herons survey lead researcher Dr. Shannon Curley, may bring the pressure needed to make that happen. Protected status would support needed local management efforts, including pollutant control, habitat restoration, prevention of human disturbance, and predator management. 

Time is critical if we are to save this once-plentiful species. Pressure from conservation groups and the general public has brought about fundamental change before, saving millions of birds’ lives. It is time to do it again. 

“The Black-crowned Night Heron could be the Passenger Pigeon of our day and disappear into extinction, or it could become a conservation success story like the Bald Eagle,” says Jessica Wilson, executive director. “Let’s work together to make it a success story.” 

Have you noticed fewer Black-crowned Night Herons in your local park? Share your observations of these birds out in the field, or tell us why they matter to you. Your experiences can help us build support for their protection before it’s too late. Send your stories to bcnh@nycbirdalliance.org.