Distinguishing Characteristics

Large, gray brown to dull cinnamon rail with slender, slightly decurved bill. Body laterally compressed, and legs and toes long relative to body size. Second in size to King Rail (Rallus elegans) among North American rails; total adult length 32–41 cm, mass 160–400 g. Sexes alike in plumage, but males average 20% larger than females. Base and sides of bill bright flesh to bright orange in males, duller in females. Adult coloration highly variable, ranging from grayish brown to cinnamon brown. Ventral coloration uniform; darker on back. Back-feathers have blackish or dusky centers of varying width. Flanks marked with alternate white and dusky to dull black bars. Color morphs described; may pertain to individual variation, age differences in plumage, plumage wear, or hybridization with King Rail (Meanley 1969, 1985, Ripley 1977, WRE). Juveniles have paler bill. Juvenal plumage varies from very dull gray to dark gray, with nearly black flanks and sides; streaking on flanks and undertail-coverts indistinct. Downy young black and difficult to distinguish from young of King Rail or Virginia Rail (Rallus limicola).

Clapper Rail is similar in appearance to King Rail; often difficult to distinguish the 2 species. Generally, Clapper Rail is smaller than King Rail. In areas where both species occur (e.g., Louisiana coast, Chesapeake Bay), overall color of most Clapper Rails grayish or dull brown; King Rail more rufescent (Meanley 1985). Most Clapper Rails have grayish face and olive brown to olive russet lesser wing-coverts (bend of wing); edges of feathers of upperparts ashy gray, washed with olive or brownish, but never with lively buff tone (Oberholser 1937, Ridgway and Friedmann 1941, Stevenson and Anderson 1994). In contrast, King Rail usually has russet to chestnut lesser wing-coverts; lively buff edges of feathers of upperparts, washed with olive or brownish; and brownish face. Width of interorbital bridge narrower in Clapper Rail than in King Rail, presumably because of more developed salt gland in Clapper Rail (Olson 1997). Vocalizations of Clapper Rail are delivered more rapidly on average, although great overlap in this trait with King Rail makes it of little utility for distinguishing the 2 species (Meanley 1969). Most Clapper Rail subspecies (yumanensis is an exception) are restricted to salt marshes or mangrove swamps, while King Rail occurs in fresh water or brackish marshes. The large rail of inland Mexico, R. elegans tenuirostris, has the rufous coloration and is considered a subspecies of King Rail (Warner and Dickerman 1959, Am. Ornithol. Union 1983, Howell and Webb 1995), although sometimes considered most similar to Clapper Rail (Oberholser 1937, Williams 1989).

Hybridizes readily with King Rail in habitats of intermediate salinity on East and Gulf Coasts of U.S. (Meanley 1985). Hybrids may be intermediate in coloration and size, but individual birds from sites where hybridization occurs may show wide variation from typical Clapper Rail plumage to typical King Rail plumage (Meanley 1969).

Virginia Rail noticeably smaller, with grayer cheeks and brighter bill color. Similar in plumage to Wetmore’s Rail (Rallus wetmorei) which overlaps in range in Venezuelan mangrove swamps, but distinguished by larger size, bolder plumage coloration, and longer 10th primary (Ripley 1977).