The Common moorhen (Gallinula chloropus) is a bird species in the rail family (Rallidae) found across many parts of the Old World. These birds live around well-vegetated marshes, ponds, canals, and other wetlands. The word 'moor' as a part of their name is an old sense meaning marsh.
Common moorhens have predominantly black and brown plumage, with the exception of a white under-tail, white streaks on the flanks, yellow legs, and a red frontal shield. The bill is red with a yellow tip. 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.
Сommon moorhens are widespread across Europe, Asia, and Africa. Populations in areas where the waters freeze, such as eastern Europe, will migrate to more temperate climates. In China, Common moorhens are largely resident south of the Yangtze River, whilst northern populations migrate in the winter. These birds live around well-vegetated marshes, ponds, canals, and other wetlands. They can even be found in city parks and urban areas.
Сommon moorhens are diurnal birds that spend their time swimming or walking along the shore. They forage beside or in the water, sometimes walking on lilypads or upending in the water to feed. They are often secretive but can become tame in some areas. Outside of the breeding season, Common moorhens prefer to spend their time alone; however, during the winter they may gather in groups to feed on sheltered lakes and ponds. To communicate with each other, these birds will give a wide range of gargling calls and will emit loud hisses when threatened.
Сommon moorhens have an omnivorous diet. They feed on a wide variety of vegetable material, seeds, and small aquatic creatures. The birds will also consume small fish, algae, insects, tadpoles, grass, berries, worms, and even snails.
Сommon moorhens are monogamous and territorial. They form pair-bonds that may last for several years. Pairs nest solitarily usually on top of thick mats of aquatic plants but may also nest in trees, shrubs, or on the ground in dense vegetation. Their nest is a wide shallow cup made with dead vegetation and lined with grass and leaves. Laying starts in spring, between mid-March and mid-May in Northern Hemisphere temperate regions. About 8 eggs are usually laid per female early in the season. Incubation lasts about three weeks. The chicks are precocial; they are hatched with eyes open and are covered in blackish down. Both parents incubate and feed the young. They fledge after 40-50 days, become independent usually a few weeks thereafter, and may raise their first brood the next spring.
Сommon moorhens are widespread across their wide range. However, in some areas populations of this species suffer from severe weather, habitat loss, pollution, and hunting. These birds are also sensitive to avian influenza disease and avian botulism which outbreaks can be a threat in the future.
It’s been discovered that their apparent nervous tic, the constant flirting of the tail, is exactly that: a nervous tic. But it has a purpose. The flicking reveals the bird’s white bottom, and this is a signal to a predator that the individual is awake and vigilant and therefore primed to flee from any planned attack. The closer the moorhen is to danger, or the more exposed it feels, the more rapidly it flicks.
The orange-red bill with a bright yellow tip is actually coded so other moorhens can tell how healthy an individual is - much as flamingos do. Scientists have shown the different colours on the bird’s bill are actually health indicators. The red seems to be related to low levels of bacterial infection, and the yellow to blood parameters such as resistance to infection. The brighter the colours, the more attractive the bird is deemed.