Subspecies
About one dozen subspecies are today considered valid; several more have been described which are now considered junior synonyms. Most are not very readily recognizable as differences are rather subtle and often clinal. Usually, the location of a sighting is the most reliable indication as to subspecies identification, but the migratory tendencies of this species make identifications based on location not completely reliable. Old World birds have a frontal shield with rounded top and fairly parallel sides; the tailward margin of the red unfeathered area is a smooth waving line. American birds have a frontal shield that has a fairly straight top and is less wide towards the bill, giving a marked indentation to the back margin of the red area.
In addition to the extant subspecies listed below, there are two Pleistocene populations known from fossils; they were distinct (generally larger) birds and probably the direct ancestors of some of today's Common Moorhens: The stout and long-winged paleosubspecies G. c. brodkorbi is known from the Ichetucknee River deposits in Florida; it was originally described as a distinct species. The presence of fossils typical of the shorter-winged and more delicate G. c. cerceris in the same deposits suggests that brodkorbi was not ancestral to the "Florida Gallinule" of our time but rather to the more northernly "Common Gallinule". An undescribed form is recorded from the Early Pleistocene of Dursunlu in Turkey.
| List of subspecies by date of description | |||
|---|---|---|---|
| Common and trinomial names |
Description | Range | |
| Eurasian Common Moorhen G. c. chloropus Includes correiana and indica. |
|
Wings and back blackish-olive | Ranges from Northwest Europe to North Africa and eastwards to Central Siberia and from the humid regions of southern Asia to Japan and Central Malaysia; also found in Sri Lanka and the Canary, Azores, Madeira, and Cape Verde islands. |
| Southern American Common Moorhen G. c. galeata |
|
Wings and back are fairly uniform dark brownish slate grey. | Found in Trinidad, the Guyanas, and from Brazil south of the Amazonas to North Argentina and Uruguay. |
| Indo-Pacific Common Moorhen G. c. orientalis |
Small, with slate grey upperwing coverts and large frontal shield. | Found in the Seychelles, Andaman Islands, and South Malaysia through Indonesia; also found in the Philippines and Palau. The breeding population existing on Yap in Micronesia since the 1980s is probably of this subspecies, but might be of the rare G. c. guami. Population size: Perhaps a few 100s on Palau as of the early 2000s, less than 100 on Yap as of the early 2000s. |
|
| African Common Moorhen G. c. meridionalis |
Similar to orientalis, but the frontal shield is smaller. | Found in Sub-Saharan Africa and Saint Helena. | |
| Madagascan Common Moorhen G. c. pyrrhorrhoa |
Similar to meridionalis, but the undertail coverts are buff. | Found on the islands of Madagascar, Réunion, Mauritius, and the Comoros. | |
| Andean Common Moorhen G. c. garmani |
Similar to galeata, but larger. | Found in the Andes from Peru to Northwest Argentina. | |
| Hawaiian Moorhen G. c. sandvicensis Called ʻalae ʻula ("red Hawaiian Coot") in Hawaiian. |
|
Has a large frontal shield; the tarsus is reddish-orange in front. | Endemic to the Hawaiian Islands. |
| Antillean Common Moorhen G. c. cerceris The now-obselete name of Florida Gallinule was once used the U.S. |
|
Has a long bill and large feet and is less brown above. | Found in the Antilles, except Trinidad and Barbados; also found in South Florida. |
| North American Common Moorhen G. c. cachinnans Also known as Common Gallinule and Marsh Hen. |
|
Similar to cerceris, but upperparts coloration more like chloropus. | Ranges from Southeast Canada south through the USA, excluding the Great Plains region, to West Panama; also found in the Galápagos and Bermuda. |
| Subandean Common Moorhen G. c. pauxilla |
Similar to cerceris, but smaller. | Found in lowland areas of East Panama south to Northwest Peru. | |
| Mariana Common Moorhen G. c. guami Called pulattat in Chamorro. |
Body plumage is very dark. | Endemic to the Northern Mariana Islands, but see also G. c. orientalis above. Population size: About 300 as of 2001. |
|
| Barbados Moorhen G. c. barbadensis |
Similar to cerceris, but with lighter head and neck, and less dull grey overall. | Endemic to Barbados. | |
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