Clapper Rail Life History

Habitat

Clapper Rails live in saltmarshes with extensive vegetation, which they use as refuges, especially at high tide. These birds prefer low portions of coastal wetlands dominated by cordgrass (spartina), pickleweed, mangroves, and other vegetation.Back to top

Food

Clapper Rails are opportunistic and omnivorous, eating whatever's available including crabs, crustaceans, fish, eggs, and plant matter. Fiddler crabs are a favorite item if they can be found. They eat vegetation and seeds more often in the winter than in the summer. Clapper Rails forage while hidden in vegetation, or along the edges between marshes and mudflats. They find prey by sight and possibly by smell, usually grabbing food items from the surface or making shallow probes into the ground. Many prey are swallowed whole, and pellets of indigestible material (such as clam shells) are later regurgitated. Clapper Rails sometimes wash debris from clams before eating.Back to top

Nesting

Nest Placement

Nest site selection involves a compromise between sites at higher elevation (to avoid flooding) with less dense cover, and sites at lower elevation with denser cover and tall grasses, to remain hidden from predators. Nests are placed in clumps of vegetation or in shrubs, from just above ground level to about 4 feet off the ground. Sites with diverse vegetation are preferred.

Nest Description

Males do most of the nest building and may continue to add to the nest after the female has started incubating eggs. Nests are bulky platforms of marsh vegetation, and are tall to protect them from tidal flooding and camouflaged to keep them concealed. Nests may have domes to help keep them hidden, and ramps to enable entry and exit in habitats with high or fluctuating water levels. The outside of the nest is 7–14 inches in diameter, with an inside cup 5–6 inches across and 1.5–3 inches deep. Domes are 6-8.5 inches higher than the rim of the nest. The male may add material during periods of high water. Both sexes incubate the eggs—usually the female during the day and the male at night—and raise the young. Pairs may renest up to 5 times after the failure of previous nests.

Nesting Facts

Behavior

Clapper Rails live most of their lives on the ground, concealed amid dense vegetation. They occasionally climb into tall vegetation to investigate a sound or call of another animal. They rarely fly; they instead walk in an often irregular path with neck outstretched, and tail erect, jerking up and down if agitated. Birds may run in response to a threat, holding tail and head straight out and body horizontal. These birds spend much of their time foraging for prey, which they capture by gleaning from the surface or from shallow probes with their bills into the substrate. Clapper Rails are territorial during nesting season, but may form loose colonies, though this is less because they are social, and more because habitat availability and high water levels concentrate individuals onto higher ground. Birds respond to alarm calls and behaviors of other species. They swim well, and will dive if threatened. Clapper Rails are monogamous during the breeding season. Pairs work together to raise young. Adults may use a “broken wing” display to lead predators away from nests. They may compete directly with gulls for nest sites.Back to top

Conservation

Clapper Rails can be common in saltmarshes, but their secretive nature makes it hard to estimate their population trends with long-term surveys. The North American Breeding Bird Survey suggests numbers declined between 1966 and 2021 (likely due in part to loss of coastal wetland habitat), but there's not enough data to be certain of the trend. Partners in Flight estimates the global breeding population at 210,000 individuals and rates the species a 13 out of 20 on their Continental Concern Score, indicating a species of low conservation concern. Clapper Rails are threatened by habitat development and degradation, and high tides associated with storms. Sand deposition from storms may destroy marsh grasses, and this can affect Clapper Rail populations. Land development that alters vegetation, water levels or salinity can cause local population declines. Toxic materials settle in coastal wetlands, and this might compromise Clapper Rails; the species has served as an indicator for estuary health. They are listed as game birds in most coastal states in the eastern United States.

Credits

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight (2021). Avian Conservation Assessment Database, version 2021.

Rush, S. A., K. F. Gaines, W. R. Eddleman, and C. J. Conway (2020). Clapper Rail (Rallus crepitans), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.clarai11.01

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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