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Black rail

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Black rail
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Gruiformes
Family: Rallidae
Genus: Laterallus
Species:
L. jamaicensis
Binomial name
Laterallus jamaicensis
Gmelin, 1789

The black rail (Laterallus jamaicensis) is a mouse-sized member of the bird family Rallidae.

Taxonomy

The Black Rail (Laterallus jamaicensis) belongs to the order Gruiformes and the family Rallidae.  

There are five recognized subspecies of the black rail.

The first subspecies, the Eastern Black Rail (L. j. jamaicensis), is found in eastern North America, the Caribbean, and Central America. L. j. jamaicensis is partially migratory, breeding in America and wintering further south. It has been proposed for listing as Threatened under the Endangered Species Act by the US Fish and Wildlife Service as of January 2020. The Eastern Black Rail can be differentiated from other subspecies by its gray crown and light brown nape.  [2]

The second subspecies, the California Rail, L. j. coturniculus, is found in both fresh and salt water marshes 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.[2] The California Fish and Game Commission listed  L. j. coturniculus as Threatened in 1971 due to loss of wetland habitat. [3]   

The third subspecies, the Junín Rail, L. j.tuerosi is only found in the marshes of Lake Junín, Peru. The Junín Rail is considered Endangered because of its incredibly limited range. The Junín Rail can be distinguished from other subspecies by its plain undertail coverts and pale legs.[4]

The fourth subspecies, L. j. murivagans, is 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[2]

The fifth subspecies, L. j. salinasi is found in Argentina and Chile, and is the southernmost subspecies. On average, this subspecies is larger than the rest. This subspecies can be distinguished from the rest by the large rufus patch on the upper back.   [2]


Description

The Black Rail is a small black bird with a short bill. Black Rails usually weigh 29-39g and are 10-15cm in length. 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. [2]

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.[5] The peak of vocalization is during the first two weeks of May, when breeding and courtship behaviors are also at their peak.[6]


Distribution and habitat

It is found in scattered parts of North America and the Pacific region of South America, usually in coastal salt marshes but also in some freshwater marshes. 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.[5]

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.[5]

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. [7]

Diet

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. [6]

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. [8]

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.[3]  

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 know about them to help prevent population decline.  

They are preyed upon by many avian (including hawks, egrets, and herons) and mammalian (including foxes and cats) predators and rely on the cover of thick marsh vegetation for protection. High tides are 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. IUCN. 2019. Retrieved 10 December 2019.
  2. ^ a b c d e Eddleman, W. R.; FLORES, R. E.; LEGARE, M. (1994). "Black Rail (Laterallus jamaicensis)". The Birds of North America Online. doi:10.2173/bna.123. ISSN 1061-5466.
  3. ^ a b Tsao, Danika C.; Melcer, Jr., Ronald E.; Bradbury, Michael (2015-12-17). "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.
  4. ^ "Junin Rail (Laterallus tuerosi)". www.hbw.com. Retrieved 2020-02-23.
  5. ^ a b c 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.
  6. ^ a b "Wildlife Field Guide for New Jersey's Endangered and Threatened Species - Conserve Wildlife Foundation of New Jersey". www.conservewildlifenj.org. Retrieved 2020-02-23.
  7. ^ 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.
  8. ^ "Laterallus jamaicensis: BirdLife International". IUCN Red List of Threatened Species. 2019-07-15. Retrieved 2020-02-23.
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