Common Moorhen - Description and Ecology

Description and Ecology

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. A mid-to-large sized rail, it can range from 30 to 38 cm (12 to 15 in) in length and span 50 to 62 cm (20 to 24 in) across the wings. The body mass of this species can range from 192 to 500 g (6.8 to 18 oz).

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. This species will consume a wide variety of vegetable material and small aquatic creatures. They forage beside or in the water, sometimes upending in the water to feed. 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. They fight over territories and also hop around Lily pads.

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 fewer 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.

• G. c. chloropus nest with small clutch of eggs at Wilgenhoek, Deerlijk (Belgium)

• Chick, 1–2 weeks old

• Unfledged G. c. chloropus young, about 1 month old, in Kolkata (India)

• Immature G. c. chloropus, 3–4 months old, in Parc de Bercy, Paris (France)

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 considered 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. This species is parasitised by the moorhen flea, Dasypsyllus gallinulae.