Gallinula chloropus

Family : Rallidae

Text © Dr. Gianfranco Colombo

 

English translation by Mario Beltramini

 

The Swamp chicken (Gallinula chloropus Linnaeus, 1758) belongs to the order of the Gruiformes and to the family of the Rallidae and is one of the most diffused birds in the world.

Its expansion has been uninterrupted during the last decades and has now reached unthinkable as well as unlikely locations and habitats.

Besides their ancestral habitats, it has been able to conquer sites by sure not suitable for its way of life while being an aquatic bird provided with a discreet verasatility, adapting to sites and to a feeding often well different from its normal habits.

Though endowed with short and stubby wings and of a fairly heavy flight, its has been able to conquer continents and sometimes to reach lands so much isolated and unsuitable to lead to think that its presence was a contrived work done by the man.

Yet its arrival on the Svalbard Islands, at Jan Mayen and in Greenland has been confirmed, locations surely not easy to reach even for a bird linked to the aquatic habitat and by sure absolutely unfriendly for the same.

On these present day it’s a usual fact to see these birds frolicking curious together with pigeons and mallard ducks under the benches of the park where we are quietly sitting or swimming with their typical jerky gait, with a continuous back and forward movement, with the tail straight like a banner, a very few metres away in the adjacent small lake, followed by their brood, small black and chirping tufts.

In all the countries where is present, it is commonly called hen or gallinula, rightly for its behaviour when on the ground, much similar to that of a chicken, adding then the attribute water, due to the habitat it frequents.

In England is erroneously called Moorhen, hen of the moor, though there is no relationship with its traditional habitat and this term has become with the time and in the ornithological world a usual way to indicate this kind of bird.

Conversely, it is probable that the exact origin of this vulgar name comes from merehen, hen of the lakes, rightly misspelled then in moorhen.

In German it is called Teichhuhn, in Spanish Gallineta Común, in French Gallinule poule-d’eau, in Portuguese Galinha-d’água, in Italian Gallinella d’acqua and finally, in English, rightly, Moorhen.

The etymology of the scientific name gets its origin from the Latin for the genus Gallinula, small hen and from the Greek for the species chloropus, from “khloros”, green and “pous”, foot. Hence, gallinule with green feet.

And here is an original anedocte about this bird. Though being not webbed, it is able to swim admirably by launching backwards nervous and quick shots with the feet and even being able to stay totally underwater, when menaced by external threats, leaving out in the surface only the bill for breathing, like a periscope. A technique called “water treading”.

It stays perfectly immersed and motionless in vertical position, an uneasy operation for a waterproofed bird and unable to stay under the surface due to the strong drive gotten from below.

It appears that, in order to realize this operation, the gallinule removes all air from the air sacs and forcing the exit of the air caught in the feathers.

In this position, it goes totally unobserved for long time till when the danger has gone.

Zoogeography

Seen the vastity of its range, it would be easier to state which are the areas not occupied rather than those colonized. The moorhen, in its various subspecies, at times upgraded to new species, lives extensively practically in all the continents in their temperate and tropical parts and with increasingly expanding territories. Are excluded the areas in the extreme north or south, depending on the hemispheres.

It has colonized remote oceanic islands such as St. Helena and the Seychelles, the Açores and Mauritius, the Mariana and the Kermadec Islands, the Hawaii and the Galapagos. A diffusion so ample to be considered as rather strange for a bird of that type. It is absent in the desert, mountainous zones, in the thick forests, in the steppes and in the dry prairies. The Gallinula chloropus is absent also in part of Oceania where it is replaced by the species Gallinula tenebrosa, a practically similar bird, if it had not a different colour of the feet.

Ecology-Habitat

Bird indissolubly linked to water, the moorhen lives in any habitat where this element is present.

It loves vast expanses of water rich of riparian vegetation, reed beds, marshes, area flooded even if occasionally for long periods of the year but doesn’t disdain the small irrigated ditches, the conduits, the moats that intersect the large monoculture crops, the bends of the slow flowing water rivers, artificial ponds, parks and city gardens.

It has been able to adapt and to integrate with ease to the chaotic urban life, in no way disturbed by the bustle and the mess created by a sometimes disorderly urbanization that has swept away even the quiet of peaceful or alleged peaceful sites, such as the city parks and the public gardens.

More than humans, it has a strong fear of dogs, often free for raids on the grass in spite of the prohibitions or of civic rules regularly ignored and often they are seen quickly jumping into the water when they are getting closer.

Neverthelerss, once the danger is gone, here they are again on the dry land, walking with absolute ease among the persons as if they were protected by them.

Morpho-physiology

At some distance, the livery of the moorhen is totally black in all its parts and both sexes exhibit the same plumage.

Only when at close quarters, we can note some shades and the only coloured particulars that in some seasons and depending on the age, modify slightly this livery.

The back and the wing cover is opaque olive black and without any metallic reflection whilst the abdomen is black slate, compact and translucent.

The beak, that has a slight shield going up on the front, is of a very lively vermilion red colour with the tip orange yellow.

Also the eyes have the iris bright red and are possibly the most attractive and bewitching part in this bird. The legs are fairly long and slender, with four long fingers with strong claws, of greenish colour, hence the Latin name given to the species and has a bizarre red garter at the base of the tibia just over the junction with the tarsus.

The undertail, always shown in any movement, is candid white and serves as means of communication with its similars. Finally, on the sides at the height of the underwing, stands a white line broken in half and more or less evidenced depending on the individuals.

The young are very similar to the adults when in winter livery and do not show the red of the beak and the typical black colour of the livery that, conversely, is completely olive brown.

The maturity is however reached already by the end of the first year of life.

The dimensions of this bird are almost the same in any congener of subspecies.

The weight is of about 300 g, the length is of 30 cm and the wingspan reaches the 60 cm.

Various subspecies have been classified despite their characteristics rather similar for each other.

The Gallinula chloropus chloropus, the typical form living in Europe, North Africa and with a more or less continuous stripe up to Japan and South-East Asia.

The Gallinula chloropus meridionalis, that occupies the sub-Saharan part of Africa.

The Gallinula chloropus pyrrhorrhoa, the endemic subspecies of Madagascar, Comoro Islands, Réunion and Mauritius and

The Gallinula chloropus orientalis, living in the northernmost part of Indian Ocean, the Seychelles, the Andaman Islands, the Indo Malayan Peninsula up to Indonesia and Philippines.

Ethology-Reproductive Biology

We have talked of very elongated and endowed of strong claws fingers, characteristics absolutely necessary for this bird. The long fingers, like all nails, have the purpose of facilitating the walking in shallow waters, leaning on the surface weeds without sinking.

The nails, tools that would reveal practically useless for their usual activity, are conversely the most used tools in their usual, incessant and interminable fights they undertake with their similars.

There is not a moment that competing males, even if placed at tens of metres far away, stare askance with aggressive postures and after a head down approach, start furious and violent battles with clashes with blows of paws and violent scratches followed by chases on the water and attempts to drown the competitor holding it under water.

Undoubtedly we might compare them to the fights of the bantam cocks, but done in the water, seen then the damages often they cause each other.

As a matter of fact, it is not rare to see birds with broken fingers if not even with broken legs. Yet, it’s their innate character.

A quarrelsome nature all over the year, often justified by the alleged danger of a possible invasion of its own territory or by the mutual idea that the adversary is attacking it even if placed hundred metres far away and little visible.

The moorhen, as well as the cousin Coot ([Fulica atra) choses the preventive war strategy and is always in arms against everyone.

Of course, such behaviour has reason for being during the mating time.

In this case the females are more combative and do not disdain equal combats with the rivals in order to maintain the position acquired with the male.

Despite being a monogamous subject, the male occasionally may become polygamous with a family widened to more females.

In this not frequent case, we can be present to the common deposition with broods formed by an abnormal number of eggs.

The moorhen is a very prolific species that lays twice and occasionally even thrice a year, and this undoubtedly contributes to its great success in conquering new areas.

The nest is a heap of dried weeds, of phragmites, grasses and dried leaves, often built in the reedbeds and floating.

Usually, it chooses the grassy banks of the water bodies, the edges of an islet, of a mass of mud or suspended over a bramble close to a water stream or even directly on trees covered by green climber at a height of various metres.

The nest is built by both partners who share also the brooding that lasts three weeks as an average.

The number of eggs varies considerably with a range going from 5 to 12. The eggs are fairly big, of cream colour and strngly spotted of reddish brown.

The chicks are nidifugous and leave the nest after a very few days from the birth, helped by the parents that will follow them for various weeks more although already capable to feed independently. They come to life covered by a thick black down they keep until the first juvenile moulting.

The moorhens eat all what they find along their way. Small mollusks and fishes, larvae of insects and tadpoles, algae, plants and seeds but do not disdain maize kernels, seeds and fruits. A times they predate the nests of the small birds that nidify on the ground, eating unscrupulously the nestlings as well as the eggs.

The same greed it shows in hunting is unluckily paid back by the nature with a very strong predation of its broods. Mice, mustelids and Grey herons (Ardea cinerea) are the main predators of this bird.

Particularly the latter, with its proverbial patience is able to wait for the exit of the chicks hidden into the riparian greenery and catch, one by one, the whole brood.

But the danger may come also from down below. In deep enough waters the pikes (Esox lucius) often easily catch these small floating beings. The very great prolificacy and the very vast area occupied by this bird does not raise in any way problems of survival to this species. The moorhen may exceed the 12 years of life.

Synonyms

Fulica chloropus Linnaeus, 1758.

 

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