Urban estuaries can support thriving ecosystems despite bustling human activity. Noting that bird populations can serve as a key indicator of environmental health, researchers recently investigated trends in the New York–New Jersey Harbor, home to the largest breeding population of colonial nesting wading birds (herons, egrets, ibises) in the northeastern United States.
In NYC Bird Alliance’s study, which is published in Conservation Science and Practice , data spanning 22 years showed that the overall population of these wading birds has declined by 27%, faster than average declines across North American birds. Though populations of Great Egret and Snowy Egret increased over time, Black-crowned Night Heron—the most abundant in the harbor and an important environmental indicator species—declined by 55%. Alarmingly, the researchers estimated that the Night Heron could be lost from the region as soon as 2037 if no conservation action is taken.
“Conservation action works, and our discovery of this decline while this bird is still plentiful will allow us to prevent their local extinction. As a top predator that connects to every corner of the harbor ecosystem, the Black-crowned Night Heron is a modern day ‘canary in the coal mine’ telling us something important about the health of our estuary,” said corresponding author Dustin Partridge, PhD, of the NYC Bird Alliance. “Healthier waterways brought nesting wading birds back to our city 50 years ago, and the same investment can keep the Black-crowned Night Heron here too—while improving the lives of all New Yorkers connected to our harbor.”
URL upon publication: https://onlinelibrary.wiley.com/doi/10.1111/csp2.70316
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Conservation Science and Practice
Steep declines of colonial wading birds in northeastern North America's largest breeding population
3-Jun-2026