Black rail

The black rail (Laterallus jamaicensis) is a mouse-sized member of the rail family Rallidae that occurs in both North and South America.

Black rail
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Class: Aves
Order: Gruiformes
Family: Rallidae
Genus: Laterallus
Species:
L. jamaicensis
Binomial name
Laterallus jamaicensis
(Gmelin, JF, 1789)
  Breeding
  Year-round
  Non-breeding

Taxonomy

The black rail was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the rails in the genus Rallus and coined the binomial name Rallus jamaicensis.[2] Gmelin based his description on the "Least water hen" that had been described and illustrated in 1760 by the English naturalist George Edwards in his Gleanings of Natural History.[3] Edwards had obtained a preserved specimen that had been brought to London from Jamaica by Patrick Browne. Browne had briefly mentioned the rail in his book "The Civil and Natural History of Jamaica".[4] The black rail is now placed with 12 other small rails and crakes in the genus Laterallus that was introduced in 1855 by George Robert Gray.[5][6] The genus name is a portmanteau of Rallus lateralis, a synonym of the binomial name for the rufous-sided crake, the type species of the genus. The specific epithet jamaicensis is from "Jamaica", the type locality.[7]

There are five recognized subspecies:[6]

  • California rail, L. j. coturniculus (Ridgway, 1874) – found in both fresh and salt water marshes of California and Arizona, and is a resident species. The California rail can be distinguished from other subspecies by its shorter bill, and brown crown and upper back.[8] The California Fish and Game Commission listed  L. j. coturniculus as Threatened in 1971 due to loss of wetland habitat.[9]   
  • Eastern black rail, L. j. jamaicensis (Gmelin, JF, 1789) – found in eastern North America, the Caribbean, and Central America. Nicknamed the "feathered mouse",[10] the subspecies is partially migratory, breeding in the United States and wintering further south. The US Fish and Wildlife Service declared L. j. jamaicensis a threatened species under the Endangered Species Act in October 2020.[10] The eastern black rail can be differentiated from other subspecies by its gray crown and light brown nape.[8]
  • L. j. murivagans (Riley, 1916) – found on the coast of Peru. This subspecies is over all paler, with white bars in the undertail coverts, distinguishing it from other subspecies. There is little information available on this subspecies.[8]
  • L. j. salinasi (Philippi, 1857) – found in Argentina and Chile, and is the southernmost subspecies. On average, this subspecies is larger than the other subspecies. This subspecies can be distinguished from the others by the large rufus patch on the upper back.[8]
  • Junín rail, L. j.tuerosi Fjeldså, 1983 – only found in the marshes of Lake Junín, Peru. The Junín Rail is considered Endangered because of its limited range. The Junín rail can be distinguished from other subspecies by its plain undertail coverts and pale legs.[8]

Description

The black rail is a small black bird with a short bill. Black rails usually weigh 29-39 g, are 10-15 cm in length, and have a wingspan of 8.7-11.0 in (22-28 cm)[11].The body is dark, with white speckles along the back and wings. Both the beak and legs are dark. Adults have a red eye that appears around 3 months of age. [8]

It will often make its presence known with its distinctive ki-ki-krr call or an aggressive, presumably territorial, growl. This is primarily uttered during the night, when these birds are most vocal.[12] The peak of vocalization is during the first two weeks of May, when breeding and courtship behaviors are also at their peak.[13]

Distribution and habitat

It is found in scattered parts of North America, the Caribbean, and the Pacific region of South America, usually in coastal salt marshes but also in some freshwater marshes. The most suitable habitat to find the Black Rail is within the high marshes The high marsh provides an ideal environment for the Black Rail, as it spends most of its time concealed within the vegetation found in this area. The bird's unique habitat choice is primarily driven by its foraging habits. While the Black Rail stays in the drier areas of the marsh, it strategically selects locations adjacent to the low marsh regions that experience occasional inundation during spring tides. These wetter parts of the marsh serve as essential foraging grounds where the Black Rail can find mud-dwelling invertebrates. The dry areas provide safe spaces for nesting by protecting their nests from flooding during high tide. The high marsh habitat is characterized by large stretches of grasses interspersed with patches of open salt panne. The salt panne is typically dry for the majority of the year but experiences periodic flooding during extreme spring tides. In the Florida Gulf Coast marshes, one of the most common grass species in the high marsh is the marsh-hay cordgrass, which is favored by the Black Rail.[14] It is extinct or threatened in many locations due to habitat loss. The largest populations in North America are in Florida and California.

Behaviour and ecology

The black rail is rarely seen and prefers running in the cover of the dense marsh vegetation to flying.

Breeding

This rail is territorial during the breeding season, and occasionally males will mate with two or more females.[12] The nests of this bird are placed on the ground, in dense, swampy vegetation or in patches of flooded grass. The nests are bowl-shaped and built with vegetation loosely woven.[12]

The clutch of this bird usually consists of six to eight creamy white speckled, with reddish-brown spots, eggs. These eggs are roundish and measure around 23 by 17 millimetres (0.91 by 0.67 in). They are incubated by both parents, taking shifts of approximately one hour each, for 16 to 20 days. The precocial young then hatch.

In 2015, the first ever breeding by black rails in South Carolina was captured through a  camera study. This species was once thought to be a non-breeding visitor to the state. [15]

Food and feeding

The black rail is an opportunistic feeder and consumes a wide range of food. Its diet includes seeds, insects, crustaceans and mollusks. The black rail forages by feeding along the water lines after high and low tide. [13]

Threats

Under the IUCN Red List, the black rail is listed as endangered with decreasing populations. The IUCN estimates there are between 28,000 and  92,000 mature individuals remaining. The largest threats to the Black Rail are habitat destruction and severe weather events. [16]

The wetland habitat that the black rail depends on has steadily declined through the last several decades, due to draining for development and conversion to agricultural land.[9]  

In addition to declining populations and increasing threats, the black rail is also impacted by the lack of scientific studies available. Because of the secretive and hard to observe nature of the bird, there is very little known about them to help prevent population decline.  

They are preyed upon by many avian (hawks, egrets, and herons) and mammalian (foxes and cats) predators, and rely on the cover of thick marsh vegetation for protection. High tides are a dangerous time for black rails, as they are quite vulnerable to predation outside the marsh.

References
  1. BirdLife International (2019). "Laterallus jamaicensis". IUCN Red List of Threatened Species. 2019: e.T22692353A154165751. doi:10.2305/IUCN.UK.2019-3.RLTS.T22692353A154165751.en. Retrieved 12 November 2021.
  2. Gmelin, Johann Friedrich (1789). Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1, Part 2 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. pp. 718–719.
  3. Edwards, George (1760). Gleanings of Natural History, Exhibiting Figures of Quadrupeds, Birds, Insects, Plants &c. Vol. 2. London: Printed for the author. pp. 142–143, Plate 278.
  4. Browne, Patrick (1756). The Civil and Natural History of Jamaica. London: Printed for the author, and sold by T. Osborne and J. Shipton. p. 479.
  5. Gray, George Robert (1855). Catalogue of the Genera and Subgenera of Birds Contained in the British Museum. London: British Museum. p. 120.
  6. Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (August 2022). "Flufftails, finfoots, rails, trumpeters, cranes, limpkin". IOC World Bird List Version 12.2. International Ornithologists' Union. Retrieved 13 October 2022.
  7. Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 219, 210. ISBN 978-1-4081-2501-4.
  8. Eddleman, W.R.; Flores, R.E.; Legare, M. (2020). Poole, A.F.; Gill, F.B. (eds.). "Black Rail (Laterallus jamaicensis), version 1.0". Birds of the World. Ithaca, NY, USA: Cornell Lab of Ornithology. Retrieved 13 October 2022.
  9. Tsao, Danika C.; Melcer, Jr., Ronald E.; Bradbury, Michael (2015). "Distribution and habitat associations of California Black Rail (Laterallus jamaicensis coturniculus) in the Sacramento–San Joaquin Delta". San Francisco Estuary and Watershed Science. 13 (4). doi:10.15447/sfews.2015v13iss4art4. ISSN 1546-2366.
  10. Loller, Travis (October 7, 2020). "Elusive eastern black rail threatened by rising sea levels". Associated Press.
  11. "Black Rail Identification, All About Birds, Cornell Lab of Ornithology". www.allaboutbirds.org. Retrieved 2020-09-27.
  12. Hauber, Mark E. (1 August 2014). The Book of Eggs: A Life-Size Guide to the Eggs of Six Hundred of the World's Bird Species. Chicago: University of Chicago Press. p. 58. ISBN 978-0-226-05781-1.
  13. "Wildlife Field Guide for New Jersey's Endangered and Threatened Species - Conserve Wildlife Foundation of New Jersey". www.conservewildlifenj.org. Retrieved 2020-02-23.
  14. "CODEBREAKERS: How to Find the Elusive Black Rail". aba.org. Retrieved 25 July 2023.
  15. Hand, Christine E.; Znidersic, Elizabeth; Tegeler, Amy K. (2019-06-27). "First Documentation of Eastern Black Rails (Laterallus jamaicensis jamaicensis) Breeding in South Carolina, USA in More Than a Century". Waterbirds. 42 (2): 237. doi:10.1675/063.042.0212. ISSN 1524-4695. S2CID 198258859.
  16. "Laterallus jamaicensis: BirdLife International". BirdLife International. 2019-07-15. doi:10.2305/iucn.uk.2019-3.rlts.t22692353a154165751.en. S2CID 243643160.


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