The Common Moorhen or Common Gallinule (Gallinula chloropus) is a bird in the Rail family with an almost worldwide distribution.
It lives around well-vegetated marshes, ponds, canals, etc. The species is not found in the polar regions, or many tropical rainforests. But elsewhere the Common Moorhen is likely the most commonly seen Rail species to most people, excepting the Coot in some regions.
The name mor-hen has been recorded in English since the 13th century, and the word moor here is an old sense meaning marsh - the species is not usually found in moorland. An older alternative name, Common Waterhen, is a more descriptive because of the bird's habitat.
A "Watercock" is not a male "Waterhen", but the rail species Gallicrex cinerea, not especially closely related to the Common Moorhen. "Water Rail" usually refers to Rallus aquaticus, again not closely related.
The scientific name Gallinula chloropus comes from the Latin Gallinula (a small hen or chicken) and the Greek chloropus (khloros χλωρός green or yellow, pous πούς foot).
The Moorhen is a distinctive species, with dark plumage apart from the white undertail, yellow legs and a red facial shield.
The young are browner and lack the red shield. It has a wide range of gargling calls and will emit loud hisses when threatened.
Distribution / Range
This is a common breeding bird in marsh environments and well-vegetated lakes.
Populations in areas where the waters freeze, such as southern Canada, the northern USA and eastern Europe, will migrate to more temperate climes.
It is often secretive, but can become tame in some areas. Despite loss of habitat in parts of its range, the Common Moorhen remains plentiful and widespread.
Diet / Feeding
This species will consume a wide variety of vegetable material and small aquatic creatures. They forage beside or in the water, sometimes upending (feeding upside down in water).
Nesting / Breeding
The nest is a basket built on the ground in dense vegetation. Laying starts in spring, between mid-March and mid-May in N hemisphere temperate regions.
About 8 eggs are usually laid per female early in the season; a brood later in the year usually has only 5-8 or even less eggs. Nests may be re-used by different females.
Incubation lasts about three weeks. Both parents incubate and feed the young. These fledge after 40–50 days, become independent usually a few weeks thereafter, and may raise their first brood the next spring. When threatened, the young may cling to the parents' body, after which the adult birds fly away to safety, carrying their offspring with them.
Status / Conservation
Despite being an abundant and widespread species, small populations are more prone to extinction. The Hawaiian Moorhen or ʻalae ʻula (G. c. sandvicensis) is suspected to be threatened by the Small Indian Mongoose (Herpestes javanicus) which was introduced to the Hawaiian Islands to hunt rats but found the local birdlife easier prey. The Mariana Common Moorhen or pulattat (G. c. guami) is very rare nowadays due to destruction of habitat. Only some 300 adult birds remained in 2001, and it is listed as Endangered both federally (since 1984) and locally.
The population of Palau, belonging to the widespread subspecies G. c. orientalis and locally known as debar (a generic term also used for ducks and meaning roughly "waterfowl"), is also very rare, and apparently the birds are hunted by locals. Most of the population on the archipelago occurs on Angaur and Peleliu, while the species is probably already gone from Koror. In the Lake Ngardok wetlands of Babeldaob, a few dozen still occur, but the total number of Common Moorhens on Palau is about in the same region as the Guam population; less than 100 adult birds (usually less than 50) have been encountered in any survey.
On a global scale – all subspecies taken together –, the Common Moorhen is as abundant as its vernacular name implies. It is therefore conmsdiered a Species of Least Concern by the IUCN.
The Common Moorhen is one of the birds (the other is the Eurasian Coot, Fulica atra) from which the cyclocoelid flatworm parasite Cyclocoelum mutabile was first described.
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 andtrinomial names, Description and Range
Eurasian Common Moorhen G. c. chloropus (Linnaeus, 1758) 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 (Lichtenstein, 1818)
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 (Horsfield, 1821)
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 MoorhenG. c. meridionalis (C. L. Brehm, 1831)
Similar to orientalis, but the frontal shield is smaller.
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