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Secretive Marsh Birds

Marsh Bird Monitoring Program

Virginia rail
Virginia rail - Carter's Pond WMA
NYSDEC - C. Osborne

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.

Wetland-dependent birds face a variety of threats, including:

  • 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).

Many marsh birds are thought to be rare or declining because of these threats. They are listed in many states as endangered, threatened, or of special concern. Several other species are regulated game birds, although rail and snipe hunting is no longer popular in many areas.

Species

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:

Rare Species
Species Status
Black Rail (Laterallus jamaicensis) Endangered
Pied-billed Grebe (Podilymbus podiceps) Threatened
King Rail (Rallus elegans) Threatened
Least Bittern (Lxobrychus exilis) Threatened
American Bittern (Botaurus lentiginosus) Special Concern

Migratory Game Birds
Species
Virginia Rail (Rallus limicola)
Clapper Rail (Rallus crepitans) - Closed Season
Sora (Porzana carolina)
American Coot (Fulica americana)
Common Gallinule (Gallinula galeata)
Wilson's Snipe (Gallinago delicata)

Conservation of marsh birds includes diverse objectives, including:

  • determining need for protection (with state/federal listing);
  • assessing efficacy of conservation initiatives and habitat management; and
  • setting responsible harvest limits.

Targeted Marsh Bird Surveys

For many species, however, population status and trends, species-specific distributions, and habitat associations are uncertain because marsh birds can be secretive and difficult to detect. Traditional avian survey methods simply do not detect enough marsh birds to address conservation objectives. These surveys include point counts or roadside surveys used by existing broad-scale monitoring programs like the North American Breeding Bird Survey (BBS) (leaves DEC website).

In order to provide wildlife managers with information about the population status of these secretive marsh birds, targeted marsh bird surveys were developed in 1998 by the North American Marsh Bird Monitoring Program (leaves DEC website). The Standardized North American Marsh Bird Monitoring Protocols (Conway 2009) (leaves DEC website) were subsequently developed. They provide an effective method of documenting presence and distribution of focal species and estimating their density and detection probabilities. The survey protocols combine passive listening with a call-broadcast period to elicit vocal responses from marsh birds. This greatly increases the chances of detecting a focal species. Measuring the habitat characteristics at survey sites, such as percent open water and dominant vegetation, helps us to understand species-habitat relationships.

National Marsh Bird Monitoring Pilot Study and Long-Term Monitoring Program

New York State Department of Environmental Conservation (NYSDEC) uses these standardized methods to monitor marsh birds throughout the state. In 2004, NYSDEC initiated a three-year study to determine occupancy of marsh bird species in emergent wetlands on public lands that could be used to guide development of a long-term monitoring plan in New York. From 2009-2011, NYSDEC 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 random sampling design to the existing standardized monitoring protocols in a collaborative effort to obtain population trend data. Currently, NYSDEC has built upon these two studies to develop and fully implement a long-term marsh bird monitoring program throughout the state.


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