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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 the loss of wetland habitat to development, wetland contamination from agricultural and industrial runoff, the replacement of hemi-marshes with dense monocultures of cattail (Typha latifolia), and the 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, and 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. 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:

black rail (Laterallus jamaicensis) - Endangered

pied-billed grebe (Podilymbus podiceps) - Threatened

king rail (Rallus elegans) - Threatened

least bittern (Ixobrychus exilis) - Threatened

American bittern (Botaurus lentiginosus) - Special Concern

Migratory Game Birds:

Virginia rail (Rallus limicola)

clapper rail (Rallus longirostrus) - Closed Season

sora (Porzana carolina)

American coot (Fulica americana)

common moorhen (Gallinula chloropus)

Wilson's snipe (Gallinago delicata)

Conservation of marsh birds includes diverse objectives like determining need for protection (with state/federal listing), assessing efficacy of conservation initiatives and habitat management, and setting responsible harvest limits. 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, such as point counts or roadside surveys used by existing broad-scale monitoring programs like the North American Breeding Bird Survey (BBS) (see "Links leaving DEC's website" at right), simply do not detect enough marsh birds to address conservation objectives.

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 (see "Links leaving DEC's website" at right). The Standardized North American Marsh Bird Monitoring Protocols (Conway 2009) (see "Links leaving DEC's website" at right) were subsequently developed, providing an effective method of documenting presence and distribution of focal species and estimate their density and detection probabilities. The survey protocols combine passive listening with a call-broadcast period to elicit vocal responses from marsh birds, greatly increasing 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.

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 (USFWS) 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 is building upon these two studies to develop and fully implement a long-term marsh bird monitoring program throughout the state.

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