Common moorhen (Gallinula chloropus)

Also known as: common gallinule, Florida gallinule, gallinule, moorhen, waterhen
  
French: Poule d'eau commune
KingdomAnimalia
PhylumChordata
ClassAves
OrderGruiformes
FamilyRallidae
GenusGallinula (1)
SizeLength: 30 - 38 cm (2)
Wingspan: 50 - 55 cm (2)
Male weight: 249 - 493 g (2)
Female weight: 192 - 343 g (2)

Classified as Least Concern (LC) on the IUCN Red List (1).

A medium-sized, ground-dwelling water bird, the striking common moorhen is among the world’s most widespread bird species, being found in many wetlands across the globe (3). It is easily recognised by its vivid red shield and short, yellow bill, which sits in stark contrast to dark-coloured plumage (4). From a distance the plump body appears bold black, but upon closer inspection it is a more attractive olive-brown on the back, head and on its short wings, and grey on the underparts (3). The short legs and the long, fully-webbed toes are bright yellow-green to yellow, and a white trim around the underside of the short tail is visible when the bird flicks its tail upwards (2) (5). The male and female adult birds are similar in appearance, although the female is typically slightly larger, but the juvenile bird has a brown to grey crown, neck and back, while the underparts are paler than those of the adult bird, with a whitish throat and belly (2) (5). The common moorhen is an extremely vocal bird capable of producing a number of bizarre, distinctive sounds, including a variety of clucks and chattering calls (5).      

The common moorhen has one of the largest ranges of any bird species, occurring on every continent except for Australasia and Antarctica, although it is just an occasional visitor to Svalbard in the Arctic. It is found as far afield as remote islands in the Pacific, such as the Hawaiian and Galapagos Islands (4) (6).

The common moorhen is an extremely versatile species capable of occupying a diversity of freshwater habitats, including slow-flowing rivers, lakes, streams, canals, ditches, swamps, marshes and flood-plains. It requires access to open water, and generally prefers waters sheltered by woodland, bushes or emergent vegetation. While foraging, it may wander away from water onto dry grassland, agricultural land or meadows (5).

A superb opportunist, the omnivorous common moorhen will feed on almost anything available for consumption, including small fish, earthworms, insects, plant matter and even birds’ eggs. Typically, it feeds alone, but occasionally groups of up to 30 animals congregate at sheltered lakes and ponds during periods of harsh weather (6). The common moorhen obtains its food from the water surface when swimming or when walking on emergent vegetation, although it will occasionally dive or dip the bill under the water to upturn floating leaves and feed on any attached invertebrates. When startled, the common moorhen usually takes cover in dense vegetation instead of fleeing, but on occasions when it does take to the air, its flight is short and laboured, with the legs dangling ungainly from the body (5). 

The common moorhen breeds during the spring, particularly in the wettest months (6). Monogamous pairs form each season and courtship begins with the male swimming towards the spectating female with the bill dipped into the water, and concludes with both birds simultaneously nibbling at each others feathers. Both birds cooperate to build a simple cup-shaped nest out of twigs on a floating mat of vegetation, or in the branches of emergent vegetation around one metre above the water. A territory around this nest is fiercely defended from other moorhens, and intruders may be repelled by aggressive charges (5). Between five to nine eggs are laid in the nest and incubated for some 17 to 22 days. After hatching, the young chicks remain in the nest for the first two days, but they are soon capable of swimming limited distances away from the nest, and are capable of diving after eight days. The chicks fledge after around 45 to 50 days, and reach maturity at a year of age (2).     

The common moorhen is a hugely abundant bird with a global population that likely numbers several million birds (6). As a supreme opportunist capable of occupying a diversity of freshwater habitats, in many places human-modification of the landscape to create reservoirs and artificial wetlands has actually increased the amount of habitat available to the common moorhen. Today, there are not thought to be any major threats to the common moorhen, although it is susceptible to avian influenza and avian botulism, and future outbreaks of these fatal diseases could potential threaten the species (6). In the UK, it is also vulnerable to predation by introduced mink, while on the Hawaiian Islands it is predated by feral dogs, cats and mongoose, and exotic plants have degraded its habitat (5) (6).

While there are no known specific conservation measures currently in place for the common moorhen, this water bird is benefiting from efforts to improve the quality of wetland habitats within its range. It also occurs in a large number of protected areas. On Hawaii, a number of conservation recommendations have been made to protect the species and its habitat, including the management of water levels in wetlands, controlling predators, creating artificial nesting sites and limiting human access and disturbances to protected areas (5).   

To find out more about the conservation of birds, see:

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  1. IUCN Red List (September, 2010)
    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.
  3. Royal Society for the Protection of Birds (September, 2010)
    http://www.rspb.org.uk/wildlife/birdguide/name/m/moorhen/
  4. Schulenberg, T.S. (2010) Common moorhen (Gallinula chloropus). In: Neotropical Birds Online. Cornell Lab of Ornithology, Ithaca. Available at:
    http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=140596
  5. Bannor, B.K. and Kiviat, E. (2002) Common moorhen (Gallinula chloropus). In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca: Available at:
    http://bna.birds.cornell.edu/bna/species/685/articles/introduction
  6. BirdLife International (September, 2010)
    http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=2937