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Final Report - New York State Marsh Bird Monitoring Program 2010 - 2017

American bittern by Matthew Walters
American bittern by Matthew Walters

Many marsh birds species are elusive, do not make many vocalizations, and are often in hard to reach wetlands. These traits have made it difficult to identify these birds during traditional surveys. It also makes estimating current marsh bird populations and trends difficult.  A survey protocol was developed to increase detection rates. However, inconsistencies among sampling designs prevented combining data from multiple locations. This is necessary to understand marsh birds at regional or continental scales.

To address this issue, New York State Department of Environmental Conservation (NYSDEC) and groups from seven other states participated in the U.S. Fish and Wildlife Service's National Marsh Bird Monitoring Program Pilot Study. The study combined rigorous sampling methods with the Standardized North American Marsh Bird Monitoring Protocols. The goal was to assess the population status of secretive marsh birds. Species included Virginia rail, sora, king rail, American bittern, least bittern, and pied-billed grebe.

Primary objectives of the three-year pilot study in NY included:

  • estimating temporal trends in marsh bird occupancy and abundance to inform management decisions regarding population health;
  • determining change in annual occupancy and abundance to inform regulatory decisions for harvested species; and documenting species-specific habitat associations at multiple scales.

From 2010 to 2017, NYSDEC conducted over 6,000 call-broadcast surveys at approximately 230 survey points in freshwater wetlands throughout upstate NY and one freshwater wetland on Long Island.

Survey points included:

  • random points from the pilot study sampling design;
  • non-random long-term monitoring points previously established by NYSDEC; and
  • new points in the freshwater managed point stratum.

From 2010-2017, a total of 88 routes were surveyed, including 63 random and 25 non-random, long-term. In 2017 DEC staff completed 645 surveys at 231 points comprising 41 survey routes (31 random and 10 non-random, long-term routes).


  • American bittern was the most commonly detected focal species with 470 detections of 69 individuals at 52 points (23% of all survey points).
  • Virginia rail was the most abundant species with 356 detections of 116 individuals at 68 points (29%).
  • Pied-billed grebes were the second most abundant species with 414 detections of 95 grebes at 55 points (24%).
  • Least bittern had 222 detections of 47 individuals at 39 points (17%).
  • Sora were detected 38 times of 23 individuals at 18 points (8%).
  • Clapper rail and king rail had 1 and 4 detections respectively of 1 individual at 1 point (<1%). 

Final Reports

New York State Marsh Bird Monitoring Program Pilot Study: 2009-2011 (PDF, 980 KB)

Eight Years of Marsh Bird Monitoring in New York State: 2010 – 2017 (PDF, 1.12 MB)