Harbor Herons Nesting Survey 2010

New York City Audubon’s Harbor Herons Project Nesting Survey of the New York Harbor and surrounding waterways was conducted between 18 and 27 May 2010, with additional observations in June and July. This report summarizes long-legged wading bird, cormorant, and gull nesting activity observed on selected islands, aids to navigation and at one mainland colony.

Species summaries:
Nine species of long-legged wading birds nested on nine islands in New York Harbor. These species, hereafter collectively referred to as waders, included -
Blackcrowned Night-Heron,
Great Egret,
Snowy Egret,
Glossy Ibis,
Yellow-crowned Night-Heron,
Little Blue Heron,
Tricolored Heron,
Cattle Egret, and
Green Heron.

Since the previous comprehensive nesting survey in 2007, varying degrees of population increase were observed for the Black-crowned Night-Heron, Yellow-crowned Night-Heron, Great Egret, Snowy Egret, and Glossy Ibis populations. The Tricolored Herons, Little Blue Herons, Green Herons, and Cattle Egrets continued to nest at low numbers. Black-crowned Night-Herons continue to be the numerically dominant nesting species in most mixed-species colonies. A total of 1,372 Double-crested Cormorant nests were observed, representing an increase from the 2007 total of 1,046 nests and the 2009 total of 1,183 nests. Gull nesting activity was observed on all surveyed islands using both adult and nest counts in 2010.

Island summaries:
The largest species diversity was observed on Canarsie Pol (eight species) as in previous years.
The greatest total number of nests was observed on Hoffman Island (624 nests), surpassing South Brother Island, which had been the largest wader colony in previous years, and continued to support a large portion of the wader community in 2010 (456 nests).
No active wader nests were observed on the three islands in the Arthur Kill and Kill Van Kull. Following an eight-year decline, this year marks the third consecutive year in which no waders were observed nesting on North Brother Island.
Wader nesting activity on Huckleberry Island continued to persist at low levels.
Mainland nesting of Yellow-crowned Night-Herons was observed at the Redfern Houses colony in Far Rockaway, where 65 nests were observed.
Double-crested Cormorants nested on eight islands, including Canarsie Pol (for the first time in the history of these surveys). Additional cormorant nests were observed on aids to navigation in the Kill Van Kull, Arthur Kill and northwestern Raritan Bay.

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