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 tidal wetlands from the northern United States to Peru and Brazil. It varies greatly over its range, and many subspecies are recognized. Although its distribution on the West Coast of the United States is limited by habitat availability, most eastern populations are abundant, inhabiting coastal areas from Massachusetts through Central America and the Caribbean. One subspecies, the Yuma Clapper Rail (R. l. yumanensis), nests in freshwater marshes of the Southwest. Most races of the Clapper Rail are sedentary, but breeding populations from southern New England to the mid-Atlantic generally winter on the southern Atlantic Coast. Clapper Rails undergo erratic dispersal movements both before and after nesting, as indicated by radiotelemetry 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 of Clapper Rail 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. 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.
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. l. insularum), California Clapper Rail (R. l. obsoletus), Light-footed Clapper Rail (R. l. levipes), and Yuma Clapper Rail (R. l. yumanensis) have limited habitats and consequently face threats from habitat loss, pollutants, urbanization, and exotic predators. The latter 3 subspecies are 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. Much study since 1980 has focused on endangered western subspecies. 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.
Aspects of the taxonomy of this species remain unresolved, especially its relationship to R. elegans, the King Rail. Clearly a close sister species, King Rail has been considered as conspecific with the Clapper by some workers. If so, then taxonomists will need to determine which of the many races in this subspecies-rich complex are valid, and which belong to which parent species.