Editor’s Note (August 2016): Maps, rich media, and text have been updated to reflect a taxonomic change/split for this species. This species account is still being edited and may contain content from an earlier version of the account.
A characteristic species of salt marshes and mangrove swamps, this large, gray to dull cinnamon-buff rail breeds in coastal wetlands along the Atlantic and Gulf Coasts of the United States, also in the Yucatan and Caribbean. The Clapper Rail varies considerably over its range, and 10 subspecies are recognized. Most subspecies are sedentary, but breeding populations from southern New England to the mid-Atlantic generally migrate south to overwinter on the southern Atlantic Coast. Clapper Rails undergo erratic dispersal movements both before and after nesting, as indicated by radio-telemetry studies and by occasional inland or extralimital records.
Clapper Rails typically feed on crustaceans, but they take a variety of other foods if crustaceans are unavailable. Males average larger in size and mass than females, but the sexes are alike in plumage. Both sexes assist in incubation and brood rearing, suggesting that the species is monogamous. Nest success is typically high in high-quality habitats; flooding and predation are the principal causes of nest failure. Clapper Rail pairs may renest up to 5 times after failure of previous nests, allowing populations to withstand significant nest loss. The species is hunted locally in many Atlantic and Gulf Coast states, but little is known about adult and juvenile survival associated with hunting.
Clapper Rail populations in the eastern United States appear stable, although periodic storms may cause local populations to decline temporarily. The Mangrove Clapper Rail (R. c. insularum) has more limited habitat and consequently faces threats from habitat loss, pollutants, urbanization, and exotic predators; this subspecies is listed as Endangered by the U.S. Fish and Wildlife Service [USFWS].
Although the Clapper Rail is widely distributed and often locally abundant, little is known about many aspects of its biology because this species is difficult to observe in its dense marsh habitats. Its characteristic loud advertising and territorial vocalizations, often heard, give the species its name. Several other vocalizations are heard rarely, and their functions remain poorly known.
The taxonomy of the Clapper Rail and the closely related King Rail (R. elegans) is complex, the 2 species having been considered conspecific by some authorities. However, the King Rail was recently split into 2 species (King Rail and Aztec Rail, Rallus tenuirostris), and the Clapper Rail was split into 3 species, including the Clapper Rail (see above), Ridgway's Rail (Rallus obsoletus) of the southwestern U.S. and northwestern Mexico, and Mangrove Rail (Rallus longirostris) which occupies coastal areas of South America and southern portions of Central America (Maley and Brumfield 2013).