New Research from NYC Bird Alliance Highlights Steep Declines in Black-crowned Night Herons Across the NY-NJ Harbor
New York, N.Y. (June 4, 2026) — The NY-NJ Harbor is home to the largest known breeding population of colonial nesting wading birds in the northeastern United States, but new research shows that this important population is facing steep declines.
Published in Conservation Science and Practice, a new study led by researchers from NYC Bird Alliance analyzed 22 years of nest census data for herons, egrets, and ibises across the NY-NJ Harbor. Researchers found that the overall nesting wading bird population declined by 27% between 2000 and 2022, even as the number of active nesting colonies remained relatively steady.
The decline was driven largely by two species: black-crowned night heron and glossy ibis, which declined by 55% and 59%, respectively. The study notes that black-crowned night heron, historically the Harbor’s most abundant wading bird species, could be locally lost as soon as 2037 if current trends continue.
Supported in part through a Hudson River Foundation research grant, this long-term study helps deepen understanding of ecological change and underscores the need for further research to better understand and respond to wading bird declines across the region.
