The King Rail is one of the larger members of this secretive family, many of whom have limited geographic ranges or ecological niches. At least 11 of 143 described species of rails and allied species had become extinct by 1990 (Monroe and Sibley 1993). King Rail appears closely related to the partly sympatric, but more widely distributed Clapper Rail (R. longirostris) and the two species have been considered conspecific by some authors. The taxonomy of the various populations of Clapper and King rails needs further study (Meanley 1992).
DISTRIBUTION. During the 1987-1992 field work seasons of the TBBA project, volunteers found breeding evidence for King Rails at 43 sites. Almost half (20) of these were in three latilongs: 29094 with 4 confirmed and 3 possible locations, 29095 with 2 probable and 6 possible sites and 28096 with 2 probable and 3 possible places. No other latilong had more than 3 breeding sites. As the map below shows most breeding occurs in the Coastal Prairies region (see the region map in Lockwood and Freeman ) with scattered breeding in some areas as far inland as the northern High Plains. A North American Breeding Bird Survey (BBS) map shows a similar coastal distribution from 9 routes with an annual relative abundance of 0.5-1 rail per route (Sauer et al. 2007). In Oklahoma a possible breeding site for this rail was found.in Tillman County near the Red River (Droege 2004).
Elsewhere King Rails breed in suitable habitat throughout the drainages of the lower Great Lakes, Ohio, Mississippi and Missouri rivers west to about the 99th meridian, the Gulf Coast states and the Atlantic coastal plain north to Connecticut. The species is resident in Cuba and central Mexico and northern breeders move to the Gulf and Atlantic Coasts and lower portions of the Mississippi River in winter (Meanley 1992, Howell and Webb 1995, Am. Ornithol. Union 1998).
SEASONAL OCCURRENCE. King Rails are year-round residents in Texas, breeding from late January to September based on egg collection dates from February 6 to August 12 and downy young from March 5 to August 29 (Oberholser 1974, Lockwood and Freeman 2004).
BREEDING HABITAT. King Rails breed in Texas from near sea level to about 1100 m (3700 ft) in freshwater or brackish marshes and swamps (Oberholser 1974). Nests are usually placed in aquatic vegetation (cattails, rushes, sedges) 15-46 cm (6-18 in) above shallow water. The nest, mostly built by the male, is a basket-like structure of dry grasses, sedges, rushes or cattails. It is built on a base of wet,decaying vegetation. The surrounding leaves are pulled together to form a canopy over the nest. The canopy is about 26 cm (10 in) high above the nest rim. The nest rim is about 17 cm (7 in) above ground or water level. The outside diameter averages 28 cm (11 in) and inside diameter 15 cm (6 in; Harrison 1979, Meanley 1992).
The female usually lays 10-12 (range 6-15) smooth, pale buff eggs, sparingly and irregularly spotted with browns. Both sexes share incubation which starts after completion of the clutch and lasts 21-23 days. Young leave the nest within a day after all the eggs hatch. They follow their parents who brood and feed them for at least 3 weeks before the young begin to gather some of their own food. By 9 or 10 weeks some young make short flights. Young are independent of their parents by mid- to late summer ((Harrison 1979, Meanley 1992).
STATUS. In the Coastal Prairies region this rail is common to locally abundant in appropriate wetlands (Lockwood and Freeman 2004). The map in Oberholser (1974) shows King Rails breeding well up rivers emptying into the Gulf of Mexico where TBBA field workers did not find breeding evidence. Habitat changes along these rivers are probably responsible for this change. Data from BBS surveys (Sauer et al. 2007) are insufficient to provide a biologically meaningful trend for Texas or North America. The future of this rail in this state depends on the state’s wetlands.
Text by Robert C. Tweit (2008)
American Ornithologists’ Union. 1998. Checklist of North American birds, 7th ed. Am, Ornithol. Union, Washington, DC.
Droege, M. 2004. King Rail (Rallus elegans). In Oklahoma breeding bird atlas, pp. 126-127 (D. L. Reinking, ed.). University of Oklahoma Press, Norman.
Harrison, H. H. 1979. A field guide to western birds’ nests. Houghton Mifflin, Boston, MA.
Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, New York.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.
Meanley, B.1992. King Rail (Rallus elegans). InThe birds of North America, No. 3 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
Monroe, B. L., Jr. and C. G. Sibley. 1993. A world checklist of birds. Yale University Press, New Haven, CT.
Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.
Sauer, J. R., J. E. Hines, and J. Fallon. 2007. The North American breeding bird survey, results and analysis 1966-2006. Version 7.23.2007. USGS Patuxent Wildlife Research Center, Laurel MD < http://www.mbr-pwrc.usgs.gov/bbs>