King rail (Rallus elegans)

Also known as: freshwater marsh hen, highland rail, king clapper rail, marsh hen, Mexican clapper rail, mud hen, rice chicken
Synonyms: Aramus elegans, Limnopardalus elegans, Rallus crepitans, Rallus tenuirostris
KingdomAnimalia
PhylumChordata
ClassAves
OrderGruiformes
FamilyRallidae
GenusRallus (1)
SizeLength: 33 - 48 cm (2) (3)
Wingspan: 50 cm (4)
Male weight: 271 - 490 g (2)
Female weight: 220 - 325 g (2)
Top facts

The king rail is classified as Least Concern (LC) on the IUCN Red List (1).

The largest rail species in North America (5), the king rail (Rallus elegans) is a secretive waterbird with a long, slender beak, long legs and toes, and a short, stubby tail (2) (4) (6) (7). The king rail’s slender body allows it to squeeze through dense wetland vegetation with ease (5) (7).

The male and female king rail are similar in appearance, although the female is slightly smaller and drabber than the male (2) (3) (6). This species occurs in two colour morphs, a dark morph and a pale morph. The dark morph has brownish, streaky upperparts, a reddish-orange chest, and black-and-white barring on the flanks (3) (4) (6). The chin and centre of the throat are white, and there is a pale stripe above each eye (3). The king rail has reddish eyes, pale brownish legs and feet, and a brown beak which is yellow-orange towards the base (3) (6).

In the pale morph of the king rail, the feathers on the upperparts are edged with buff rather than brown (2) (3), and its underparts are paler than those of the dark morph, being yellowish-buff with a greyish wash (3). Juvenile king rails are duller and darker than the adults and have less distinct barring on the sides (2) (3) (4).

Three subspecies of king rail are generally recognised. Rallus elegans elegans is the largest, while Rallus elegans ramsdeni is smaller and paler and Rallus elegans tenuirostris has less bold markings on its upperparts and is paler on its underparts (2) (3) (6).

The king rail uses a wide variety of different calls, including a series of ‘cheup’ or ‘chac’ notes and a loud, harsh courtship call, given both day and night, which sounds like a series of ‘kik’ or ‘kuk’ notes (2) (3) (6).

The king rail occurs in southern Ontario, Canada, south through much of the eastern United States, and into parts of Mexico and the Caribbean (2) (3) (5) (6) (8). This species’ strongholds are around the Gulf Coast in Texas, Florida and Louisiana (6). The subspecies R. e. tenuirostris is found only in central Mexico, while R. e. ramsdeni occurs on Cuba and the Isle of Pines (2) (3) (6).

Northern populations of the king rail are migratory, moving to more southerly parts of the breeding range in winter (2) (3) (6).

A largely freshwater species, the king rail inhabits a variety of marsh habitats, including marsh-shrub swamp, flooded farmland, rice fields, river margins and roadside ditches. It is occasionally also found in brackish marshes and may occur in salt marshes during migration (2) (3) (6).

The king rail tends to prefer marsh habitats containing grasses, sedges, rushes and cattails (Typha species), as well as a range of other wetland vegetation on coastal plains (2) (3) (6). This species generally requires large marshes that contain a variety of specific habitat types and a range of different water levels (5) (7).

Usually active during the day, the king rail is a secretive bird that forages within or near to cover, usually in areas of shallow water, or sometimes on land (2) (4) (6). Its diet consists primarily of crustaceans such as crayfish and crabs, although it will also eat insects, molluscs, spiders, small fish, frogs, tadpoles and seeds (2) (3) (4) (6). The king rail may swallow small crustaceans whole, but larger prey is generally broken into pieces before being eaten (6).

In southern parts of its range, the king rail may begin breeding as early as February, but in other areas the breeding season usually runs from around March to August or September (2) (6). On arriving at the breeding grounds, the male king rail establishes a territory and chases off other males (5). The male then begins displaying to attract a female, walking around with the tail lifted and white undertail-coverts showing, and occasionally giving a loud courtship call (6). Male king rails may also present food to the female as part of courtship (4) (5) (6).

The king rail typically nests over shallow water, building a platform of dead plant material in a clump of grass or other marsh vegetation (2) (5) (6). A canopy of grass is usually constructed over the top of the nest (2) (6). Around 10 to 12 eggs are normally laid, and are incubated by both adults for 21 to 24 days (2). The downy black chicks are able to leave the nest soon after hatching and are cared for by both adults (2) (6), becoming independent at around six to ten weeks old (2).

The king rail is likely to start breeding at one to two years old (2) (5), and in southern parts of its range this species may rear two broods of young in each breeding season (2).

Although the king rail has a large range and is not currently considered to be globally threatened, it is believed to have undergone significant declines in recent decades (2) (3) (4) (6) (8). The main cause of these declines is the widespread loss and degradation of wetland habitats. The king rail is also likely to be affected by the use of pesticides, and some individuals are killed on roads, in traps set for muskrats (Ondatra zibethicus), or through collisions with buildings (2) (3) (6) (7).

The king rail is listed as a game bird in 13 U.S. states, although it is now rarely hunted (3) (6) (7). This species is listed as ‘Endangered’, ‘Threatened’ or of ‘Special Concern’ in a number of U.S. states (2) (3) (7) and is considered to be ‘Endangered’ in Canada, where its population is likely to number fewer than 100 individuals (7). In addition to extensive loss of wetlands in its Canadian range, the king rail faces threats from invasive wetland plants, as well as from the introduced common carp (Cyprinus carpio), which can reduce water quality and therefore prey availability (7) (9). A decrease in the crayfish population in Ontario could also affect food availability for the king rail (7).

The subspecies R. e. tenuirostris of central Mexico has a fairly restricted range, where it is threatened by the destruction of freshwater marshes for agricultural, industrial and urban development. The status of the subspecies R. e. ramsdeni is not currently known (2) (3).

One of the most important measures for the future survival of the king rail will be the protection of a complex mosaic of wetland habitats on wildlife refuges (2) (3) (6). These habitats should include suitable shallow, tussocky areas with dense vegetation for cover and nesting, as well as drier patches in which the young king rails can forage (2) (3).

In Canada, the king rail is protected under the Species at Risk Act (SARA) and the Migratory Birds Convention Act, which make it an offence to kill, harm, capture or possess this species or its eggs or chicks. The king rail and its habitat are also protected under Ontario’s Endangered Species Act, 2007 (5) (7). A recovery plan is in place for the king rail in Canada, and recommended conservation measures include surveying and monitoring its population, protecting and managing its habitat, and undertaking further research into the species (6) (9).

In the United States, the king rail is a U.S. Fish and Wildlife Service ‘Focal Species’, identified as needing conservation attention. A conservation plan is in place, and further research into and monitoring of the king rail and its habitat are needed. The status and distribution of this elusive waterbird in Mexico and Cuba should also be investigated (10).

Find out more about the king rail and its conservation:

More information on bird conservation in North America:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (August, 2013)
    http://www.iucnredlist.org/
  2. del Hoyo, J., Elliott, A. and Sargatal, J. (1996) Handbook of the Birds of the World. Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona. Available at:
    http://www.hbw.com/
  3. Taylor, B. and van Perlo, B. (1998) Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World. A&C Black Publishers, London.
  4. The Cornell Lab of Ornithology: All About Birds - King rail (August, 2013)
    http://www.allaboutbirds.org/guide/King_Rail/id
  5. Government of Canada: Species at Risk Public Registry - King rail (August, 2013)
    http://www.sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=24
  6. Poole, A.F., Bevier, L.R., Marantz, C.A. and Meanley, B. (2005) King rail (Rallus elegans). In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca. Available at:
    http://bna.birds.cornell.edu/bna/species/003/
  7. COSEWIC (2011) COSEWIC Assessment and Status Report on the King Rail Rallus elegans in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. Available at:
    http://publications.gc.ca/collections/collection_2012/ec/CW69-14-3-2011-eng.pdf
  8. BirdLife International - King rail (August, 2013)
    http://www.birdlife.org/datazone/speciesfactsheet.php?id=2865
  9. Environment Canada (2012) Recovery Strategy for the King Rail (Rallus elegans) in Canada. Species at Risk Act Recovery Strategy Series, Environment Canada, Ottawa. Available at:
    http://www.sararegistry.gc.ca/virtual_sara/files/plans/rs_king_rail_e.pdf
  10. Cooper, T.R. (2008) King Rail Conservation Plan, Version 1. U.S. Fish and Wildlife Service, Fort Snelling, Minnesota. Available at:
    http://www.fws.gov/midwest/MidwestBird/FocalSpecies/documents/KingRailConservationPlan.pdf