The moorhen is a distinctive species, with dark plumage apart from the white undertail, yellow legs and a red frontal shield. The young are browner and lack the red shield. The frontal shield of the adult has a rounded top and fairly parallel sides; the tailward margin of the red unfeathered area is a smooth waving line. In the related common gallinule of the Americas, the frontal shield has a fairly straight top and is less wide towards the bill, giving a marked indentation to the back margin of the red area.
The common moorhen gives a wide range of gargling calls and will emit loud hisses when threatened. A midsized to large 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 17.6 oz).
The species breeds in solitary territorial pairs during wet months (the exact timing varying geographically) (del Hoyo et al. 1996).It remains largely solitary throughout the year although juveniles and adults may form diurnal feeding groups especially during hard weather (Taylor and van Perlo 1998).
The common moorhen is omnivorous and feeds while walking on plants or while floating on the water. It swims across the water to scoop up floating seeds and other materials from plants floating on the surface of the water. It also dives to gather the seeds, leaves and roots of aquatic plants. On land it walks with a high-stepping gait and pecks at the ground like a chicken. It also eats algae, small fish, tadpoles, insects, berries, grass, snails, insects and worms.
The nest varies between a shallow saucer and a deep cup constructed from twigs and waterside vegetation, and can be floating on or positioned up to 1 m above water in emergent vegetation, or positioned on a solid platform of branches in water. Less often the nest is placed in ground vegetation or in low bushes on the bank near water, or in bushes and trees up to 8 m from the ground (del Hoyo et al. 1996).
Common Moorhen both male and female birds help to build the nest of floating vegetation. Nests of the Moorhen are built on the water or very close by. The male carries the materials and the female arranges them. Nests are also stages for courtship, and it is ritualized and courtship chasing also associated with pair formation.
The Common Moorhen usually lay from five to eleven eggs that are greenish white with spots. However some study shows that the Common Moorhen lays three to four eggs in the tropics.
The Common Moorhen nest has a wide shallow cup in the center for the eggs, may be partly floating. Adults eat the eggshells after the chicks hatch. They feed the chicks soon after hatching, mostly insects and their larvae.
Common Moorhen is a protected bird in the Maldives since 22nd May 2003; hence, their capture, sale and captivity have been prohibited. However, there are no vital conservation measures taken to protect the nesting habitats of Common Moorhen.