Secretive Marsh Birds
New York's Marsh Birds
Marsh birds are a group of waterbirds including rails, bitterns, grebes, gallinules, and snipe that typically inhabit dense, emergent wetlands. These species are known for their secretive nature. They are seldom seen or heard because they vocalize infrequently and prefer inaccessible wetland habitat. In New York State, five marsh bird species are state-listed as endangered, threatened, or species of special concern, while six species are state-regulated migratory game birds:
| Protected Species | Migratory Game Birds |
|---|---|
| Black Rail (Laterallus jamaicensis) | Virginia Rail (Rallus limicola) |
| Pied-billed Grebe (Podilymbus podiceps) | Clapper Rail (Rallus crepitans) - Closed Season |
| King Rail (Rallus elegans) | Sora (Porzana Carolina) |
| Least Bittern (Lxobrychus exilis) | American Coot (Fulica Americana) |
| American Bittern (Botaurus lentiginosus) | Common Gallinule (Gallinula galeata) |
| Wilson's Snipe (Gallinago delicate) |
Conservation and Management
Wetland-dependent birds face a variety of threats, such as:
- loss of wetland habitat to development;
- wetland contamination from agricultural and industrial runoff;
- replacement of hemi-marshes with dense monocultures of cattail (Typha latifolia); and
- invasion of non-native plant species, such as purple loosestrife (Lythrum salicaria) and phragmites (Phragmites australis).
Conservation actions for marsh birds includes diverse objectives, including:
- protecting wetlands
- habitat management, such as changing water levels with drawdowns or removal of invasive plants;
- assessing effectiveness of habitat management;
- monitoring trends in distribution and abundance;
- determining whether a species needs protection (with state/federal listing); and
- setting responsible harvest limits.
Targeted Marsh Bird Surveys
Marsh birds tend to be secretive and difficult to detect. They also live in wetlands that might only accessible by boat. For these reasons, typical bird survey methods like point counts or roadside surveys don't work well for marsh birds. But wildlife managers need good quality survey data to understand population status and trends, distribution, and habitat associations.
To meet this need, the North American Marsh Bird Monitoring Program (leaves DEC website) developed targeted marsh bird surveys in 1998. The Standardized North American Marsh Bird Monitoring Protocols (leaves DEC website) were developed by Courtney Conway in 2009. The survey protocols combine passive listening with a call-broadcast period to cause vocal responses from marsh birds. This method greatly increases the chances of detecting rails, bitterns, grebes, and other marsh birds. Measuring habitat characteristics at survey sites also sheds light on species-habitat relationships. DEC uses these protocols in its marsh bird surveys.
DEC's Marsh Bird Monitoring Program
In 2004, the DEC initiated a three-year study to determine occupancy of marsh bird species in emergent wetlands on public lands to guide development of a long-term monitoring plan. From 2009-2011, the DEC collaborated with U.S. Fish & Wildlife Service Division of Migratory Bird Management as one of seven states to participate in the National Marsh Bird Monitoring Program Pilot Study. The pilot study added a rigorous method of locating survey points to the standardized survey protocols, to obtain population trend data at regional and continental scales. DEC built-up these two studies to develop and implement a long-term marsh bird monitoring program throughout the state. Currently, DEC conducts annual marsh bird surveys.
The objectives of DEC's Marsh Bird Monitoring Program are to:
- Continue to contribute to regional and continental marsh bird programs to estimate trends over time in marsh bird detection, occupancy, and population size to guide management decisions regarding population health and recommended conservation status (e.g. determine if a species is of special concern, threatened, or endangered).
- Assess effects of management efforts by conducting long term surveys at randomly selected managed marsh areas to document the response of marsh birds to management actions over time such as marsh drawdowns/re-flooding, channeling and potholing in dense vegetation areas, invasive species management, and changes to management regimes and abilities.
- Determine changes in annual occupancy and population size to guide regulatory decisions for migratory game bird species, such as rails, gallinules, and snipe.
- Document species-specific habitat associations at multiple scales.
- Identify breeding locations for the rarest marsh bird species (including King Rail and Black Rail) to allow for management and protection targeted to their needs.
Survey Results
From 2010 to 2018, DEC conducted over 6,000 call-broadcast surveys at approximately 230 survey points in freshwater wetlands throughout upstate NY. Virginia rail is the most frequently detected species, followed by American bittern and pied-billed grebe. These three species are typically detected at about a quarter of all survey points each year. Least bittern is generally found only in high quality wetlands with dense cattails, less than 20% of the survey points each year. Sora is typically detected at less than 10% of the survey points. King rail is rarely detected, typically only one per year.
Results are summarized in the following reports:
New York State Marsh Bird Monitoring Program Pilot Study: 2009-2011 (PDF)
Eight Years of Marsh Bird Monitoring in New York State: 2010-2017 (PDF)
More About Marsh Birds
The Saltmarsh Habitat and Avian Research Program (leaves DEC webpage) uses the same methods to track coastal marsh bird populations from Maine to Virginia. There are numerous survey routes in tidal marshes throughout Long Island.
