Water Rail
Encyclopedia
The Water Rail is a bird
of the rail family
which breeds in well-vegetated wetland
s across Europe, Asia and North Africa
. Northern and eastern populations are migratory
, but this species
is a permanent resident in the warmer parts of its breeding range. The adult is 23–28 cm (9–11 in) long, and, like other rails, has a body that is flattened laterally to allow it easier passage through the reed bed
s it inhabits. It has mainly brown upperparts and blue-grey underparts, black barring on the flanks, long toes, a short tail and a long reddish bill. The eastern subspecies
, R. a. indicus, has distinctive markings and a call that is very different from the pig-like squeal of the western races, and is sometimes split as a separate species. Immature birds are generally similar in appearance to the adults, but the blue-grey in the plumage
is replaced by buff. The downy chicks are black, as with all rails.
The Water Rail breeds in reed beds and other marshy sites with tall, dense vegetation, building its nest a little above the water level from whatever plants are available nearby. The off-white, blotched eggs are incubated
mainly by the female, and the precocial
downy chicks hatch in 19–22 days. The female will defend her eggs and brood against intruders, or move them to another location if they are discovered. This species can breed after its first year, and it normally raises two clutches
in each season. Water Rails are omnivorous
, although they feed mainly on animals. They are territorial even after breeding, and will aggressively defend feeding areas in winter.
These rails are vulnerable to flooding or freezing conditions, loss of habitat and predation by mammals and large birds. The introduced American mink
has exterminated some island populations, but overall the species' huge range and large numbers mean that it is not considered to be threatened.
are a bird family
comprising nearly 150 species. Although the origins of the group are lost in antiquity, the largest number of species and the most primitive forms are found in the Old World
, suggesting that this family originated there. However, the genus Rallus
, the group of long-billed reed bed specialists to which the Water Rail belongs, arose in the New World
. Its Old World members, the Water, African
and Madagascar Rail
s, form a superspecies
, and are thought to have evolved
from a single invasion from across the Atlantic. Gene
tic evidence suggests that the Water Rail is the most closely related of its genus to the Pacific Gallirallus
rails, and is basal
to that group. The Water Rail was first described by Linnaeus in his Systema Naturae
in 1758 under its current scientific name, Rallus aquaticus. The binomial name
is the Latin
equivalent of the English "Water Rail".
The subspecies R. a. indicus has, in addition to its distinctive plumage, very different vocalisations to the other subspecies, and it was considered a separate species in early works, including the first edition (1898) of Fauna of British India, but later demoted to a subspecies by E. C. Stuart Baker
in the second edition (1929). It was restored as a full species, the Eastern Water Rail, R. indicus, by Pamela Rasmussen
in her Birds of South Asia
(2005). Rasmussen, an expert on Asian birds, also renamed the other forms as the Western Water Rail. Her treatment has not otherwise been widely adopted, but is followed in Birds of Malaysia and Singapore (2010). A 2010 study of molecular phylogeny further supported the possibility of specific status for R. a. indicus, which is estimated to have diverged from the western forms around 534,000 years ago. The paper also suggested that the differences between the three other races were clinal, and that they should all be merged into R. a. aquaticus.
s of an ancestral Water Rail are bones from Carpathia
dated to the Pliocene
(5.3–1.8 million years ago). By the late Pleistocene
, two million years ago, the fossil evidence suggests that the Water Rail was present across most of its present range. This species is surprisingly well recorded, with over 30 records from Bulgaria alone, and many others from across southern Europe. and China. A rail from Eivissa
, Rallus eivissensis
, was smaller but more robust than than the Water Rail, and probably had poorer flight abilities. In the Quaternary
, the island lacked terrestrial mammals, and this distinctive form was presumably descended from its continental relative. It became extinct at about the same time as humans arrived on the island, between 16,700 and 5,300 BC. The nominate race of Water Rail is now a very rare resident on Eivissa.
are red, and the legs are flesh-brown. The sexes are similar; although the female averages slightly smaller than the male, with a more slender bill, determining sex through measurements alone is unreliable. The juvenile has a blackish crown and a white chin and throat. The underparts are buff or white with darker bars, and the flank markings are brown and buff, rather than black and white. The undertail is buff, and the eye, bill and leg colours are duller than the adult. The downy chick is all black apart from a mainly white bill. After breeding, the rail has an extensive moult, and is flightless for about three weeks. Individual adults can be identified by the markings on the undertail, which are unique to each bird. Adult males have the strongest black undertail streaks. It has been suggested that the dark barring on the undertail of this species is a compromise between the signalling function of a pure white undertail, as found in open water or gregarious species like the Common Moorhen
, and the need to avoid being too conspicuous.
The Water Rail can readily be distinguished from most other reed bed rails by its white undertail and red bill; the latter is a little longer than the rest of the rail's head (55–58% of the total) and slightly down-curved. The somewhat similar Slaty-breasted Rail
of tropical Asia has a stouter bill, a chestnut crown and white-spotted upperparts. Juvenile and freshly moulted Water Rails may show a buff undertail like Spotted Crake
, but that species' plumage is spotted with white, and it has a much shorter, mainly yellowish bill. The range of the Water Rail does not overlap with that of any other Rallus species, but vagrants could be distinguished from their American relatives by the lack of rufous or chestnut on the closed wing. The larger African Rail
has unstreaked darker brown upperparts and brighter red legs and feet.
The call of the subspecies R. a. indicus is quite different from that of the other forms. The courtship call, again given throughout the year, is a sharp piping kyu, longer and clearer than that of the European race. The song is a series of metallic slurred shrink, shrink notes, about two per second, and repeated after a short pause. The eastern race does not respond to recorded announcement calls of nominate R. a. aquaticus. When researchers played recordings of the Reed Warbler at night to attract that species for trapping, they found Water Rails and other wetland birds were also grounded, despite a lack of suitable habitat, suggesting that the rails and other nocturnal migrants recognised the warbler’s song and associated it with the marshy habitat in which it is usually found.
The Icelandic population of Water Rail, R. a. hibernans, became extinct around 1965, due to loss of habitat through the draining of wetlands, and predation by introduced American mink
. Prior to its extinction, least some birds were present year-round on the island, relying on warm volcanic springs to survive through the coldest months, but this race was also found in winter in the Faroe Islands
and Ireland, and on passage through the Western Isles
, suggesting that the Icelandic form was a partial migrant. The nominate subspecies, R. a. aquaticus is resident in the milder south and west of its range, but migrates south from areas that are subject to harsh winters. It winters within its breeding range, and also further south in North Africa, the Middle East
and the Caspian Sea
area. The peak migration period is September to October, with most birds returning to the breeding grounds from March to mid-April. A specimen of the nominate population labelled as "Baluchistan
" and collected by Richard Meinertzhagen
is considered of doubtful provenance. R. a. korejewi is another partial migrant, with some of the population wintering from Iraq and eastern Saudi Arabia eastwards through Pakistan and northern India to western China.
The subspecies R. a. indicus is mainly migratory, wintering in southern Japan, eastern China and northern Borneo
. It is uncommon in northern parts of Bangladesh, Burma, Laos, and northern and central Thailand, and does not normally reach further south in mainland southeast Asia. Migrants have been recorded on Sri Lanka in the past, although on the Indian mainland they are found mainly in the northern regions, with a few records from as far south as Mumbai
. On arrival in India, rails may be so exhausted that they can be caught by hand. The breeding birds on the Japanese island of Hokkaido
mostly migrate well south including to Korea but a few remain during winter in the coastal marshes of Honshu
.
The breeding habitat of the Water Rail is permanent wetland with still or slow-moving fresh or brackish water and dense, tall vegetation, which may include common reed
, reedmace
, irises
, bur-reed
or sedges
. In coastal areas, sea rush
is common in saltmarsh breeding sites, with sedges and bur-reed dominant in somewhat less saline environments. A study in The Netherlands and Spain showed that the rush provided better concealment than the other maritime plants. As elsewhere, nests were constructed from the nearest available plants. Where it occurs, saw-sedge
provides good breeding habitat, its tall (1.5 m, 5 ft) dense structure providing good cover for the nesting rails. The preferred habitat is Phragmites
reedbed with the plants standing in water, with a depth of 5–30 cm (2–12 in), muddy areas for feeding and a rich diversity of invertebrate
species. Locations with nearby willows or shrubs are favoured above large areas of uniform habitat. In addition to natural fresh or marine marshes, this rail may use gravel or clay excavations and peat workings as long as there is suitable habitat with good cover. It may be found in rice paddies or on floating islands, and it occurs in Kashmir in flooded sugarcane fields. A Finnish study showed that the main factor influencing the distribution of Water Rails was the extent of vegetation cover, with the highest densities in the most vegetated areas; the presence of other marshes nearby was also significant. However, factors such as temperature, rainfall, length of shore line and extent of peat
, important for some other marsh birds, were not statistically relevant. The areas with the highest densities of the rail also had the greatest numbers of three species considered at risk in Finland, the Great Reed Warbler
, Eurasian Bittern and Marsh Harrier
. The northern limit of breeding seems to be determined by the transition from nutrient-rich wetland to poorer, more acidic water. This leads to the replacement of common reed by a more open vegetation type dominated by marsh cinquefoil, which is unsuitable for the rails.
Occasionally, more unusual locations are used. One pair in Scotland nested in the open by the side of a road, and when an English nature reserve
installed nest boxes for Bearded Tits (reed "wigwam
s" with a wooden floor), rails nested both in the boxes and under the wooden floor, in the latter case sometimes with the tits in residence above. Although mainly a lowland species, the Water Rail breeds at 1,240 m (4,070 ft) in the Alps
and 2,000 m (6,560 ft) in Armenia. An Italian study suggested that reed bed birds need a minimum area of wetland for breeding, which for the Water Rail is about 1 ha (2.47 acres), although the highest densities are in marshes of 10 ha (25 acres) or more.
On migration and in winter, a wider range of wet habitats may be used, including flooded thickets or bracken. Freezing condition may force birds into more open locations such as ditches, rubbish dumps and gardens, or even out onto exposed ice. A Welsh study suggested that individual winter territories overlap, with each bird using a significant proportion of the reed bed. After site desertion in freezing weather, birds return to their former range. A density of 14 birds per hectare (6.6 per acre) was recorded. Birds wintering in Iceland rely on warm geothermal
streams, and may access streams through tunnels under the snow. When not feeding, they may shelter in holes and crevices in the solidified lava
. This species sometimes wanders well outside its normal range and vagrants
have been found in the Azores
, Madeira
, Mauritania, the Arctic
, Greenland
, Malaysia and Vietnam.
This species defends its breeding and wintering territories. Birds will charge each other with neck outstretched when breeding, sometimes both members of a pair attacking together. Large strongly-marked males are dominant in winter, when the direct aggression is replaced by sharming while standing upright on tip-toe, head jerking and bill thrusting.
and highly territorial when breeding. The birds pair off after arriving at their nesting areas, or possibly even before spring migration. In large wetlands with good conditions birds may nest 20–50 m (22–55 yd) apart. Territories vary in size, but 300 m2 (360 yd2) is typical. The pair give courting and contact calls throughout the breeding season. The male selects the nest site which he shows to the female while posturing with raised back feathers, wings arched over his back, tail spread and bill pointed vertically downwards. This display is accompanied by a loud call. Before mating, he raises his wings and tail, and bows with his bill touching his breast. The male feeds the female during courtship, and, when incubating, she may leave the nest to display to the male, walking round him, calling softly, rubbing her bill against his and taking short runs to and from him.
The nest is made from whatever wetland vegetation is available and built mostly by the male, usually in a single day. It is raised 15 cm (6 in) or more above the level of the marsh, and is sometimes constructed on clumps of roots, tree stumps or similar support. It may be built up higher if the marsh waters start to rise. The nest is 13–16 cm (5–7 in) across and about 7 cm (3 in high). It is well hidden and approached cautiously by narrow tracks. The average weight of wind-dried nests of R. a. indicus in Japan was 95 g (3.4 oz).
The typical clutch
is 6–11 eggs across most of the range, but appears to be smaller (5–8) in Kashmir at around 1,500 m (4,900 ft) altitude. Laying dates vary with location, from late March in western Europe and North Africa, to late May in Kashmir and June in Iceland. The clutch size may be smaller early or late in the breeding season. The breeding season can be extended by replacement and second clutches. The eggs are blunt and oval, smooth and slightly glossy; the colour varies from off-white to pink-buff, with reddish-brown blotches mainly at the broader end that sometimes merging into a single patch. Variation in egg size across the four subspecies is much less than differences between individual eggs; the average size of the eggs of the nominate subspecies, 36 × 26 mm, (1.4 × 1.0 in) is therefore typical for the species as a whole. The eggs weigh about 13 g, (0.46 oz), of which 7% is shell.
Both parents incubate the eggs, although the female takes the larger share of this duty. The eggs are incubated for 19–22 days to hatching, with at least 87% success, and the precocial
, downy young fledge
in another 20–30 days. Food is brought to the nest by the other adult and passed to the sitting parent who feeds the chicks, although they also find some of their own food after about five days. After fledging, the young birds fend for themselves. They can fly when aged 7–9 weeks. If a nest appears to have been discovered, the female may carry the chicks or eggs one by one to another location; the eggs are carried in the bill, but small chicks may be tucked under the wing. Sitting birds may stay on the eggs even when approached closely, or attack the intruder, or feign injury as a distraction. The Water Rail can breed after its first year, and it normally raises two broods.
Average survival after fledging has been estimated as between 17 and 20 months, with an annual survival rate slightly less than 50% per year for the first three years, and somewhat higher thereafter. The maximum recorded age is 8 years 10 months.
Water Rails are omnivorous
, although they mainly feed on animals. These include leech
es, worm
s, gastropods
, small crustacean
s, spiders, and a wide range of both terrestrial and aquatic insects and their larva
e. Small vertebrate
s such as amphibian
s, fish, birds and mammals may be killed or eaten as carrion
. Vertebrates are impaled with a strike of the bill which breaks the prey's spinal cord. Plant food, which is consumed more in autumn and winter, includes the buds, seeds, flowers, shoots and seeds of water plants, berries and fruit. In south Asia, paddy (harvested rice
kernel
s) may sometimes be eaten. The young rails are fed mainly on insects and spiders. Food obtained on land or from mud is normally washed in water before it is eaten. After rain, rails may probe soft ground for earthworms. This species will occasionally feed in the open even when not forced to do so by cold weather; Edmund Meade-Waldo
described seven rails feeding in an open meadow. Despite its skulking nature, the water Rail appears to thrive in captivity when fed on animal food such as raw meat or earthworms; one individual was taught to jump for worms suspended from a fishing rod.
Water Rails follow definite routes when feeding, frequently returning to good hunting areas. These rails are versatile and opportunist foragers. They will jump to take insects from plants, climb to find berries, or dislodge apples from trees so they can be eaten on the ground. They will kill birds by impaling or drowning them, particularly if the bird's ability to escape is restricted. They have been recorded as killing a European Greenfinch
and a King Quail in an aviary
, and small birds trapped in bird ringers'
mist net
s. One bird killed Twite
caught with it in a Heligoland trap
. They are also nest predators, particularly of small birds that nest in reeds such as the Great Reed Warbler
. Water Rails may defend a winter feeding territory, although this is smaller than when breeding, with individuals perhaps less than 10 m (11 yd) apart; favoured sites may hold hundreds of birds. Aggressive behaviour outside the breeding season may extend to attacks on other marsh rails such as Spotted
and Baillon's Crake
.
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Predators of the Water Rail include a number of mammals and large birds. The American mink was partly responsible for the extinction of the Icelandic population, and cats and dogs have also been recorded as killing this species. At least locally, otters
will also eat rails and other water birds. The Eurasian Bittern, another reed bed bird, will consume rails, as will Grey Heron
s. Water Rails are particularly vulnerable to the heron when forced out of the cover of the reeds by very high tides. Wetland-hunting harriers
are predictable predators, but more unusually, the rail has also been recorded as a prey item of the Tawny Owl
, Short-eared Owl
, Eurasian Eagle-owl, Greater Spotted Eagle
, Common Kestrel
, and night-hunting Peregrine Falcon
s.
Parasites include the sucking lice
Nirmus cuspidiculus and Pediculus ralli, the tick
Ixodes frontalis, and the louse fly
Ornithomyia avicularia. The Water Rail can be infected by the avian influenza virus and the bacterium Borrelia burgdorferi
, carried by Ixodes
ticks, which is also a human pathogen
causing Lyme disease
. Three lice
, Fulicoffula rallina, Pseudomenopon scopulacorne and Rallicola cuspidatus discovered on dead Water Rails in 2005 on the Faroe Islands
were all species that had not been found on the archipelago
previously. The parasitic flatworm
Ophthalmophagus nasciola was found in one rail's nasal sinus
, and at least three species of feather mite
have been detected on the plumage. The louse Philopterus ralli and the nematode
Strongyloides avium have been found on the subspecies R. a. indicus. The eastern subspecies is also one of the many intermediate hosts of another nematode, Gnathostoma spinigerum
, which causes human gnathostomiasis
, a disease found in Thailand, Japan and other parts of Southeast Asia. The nematode's first-stage hosts are copepod
s of the genus Cyclops
, which are consumed directly or indirectly by a wide variety of vertebrates before maturing in the third and final host, a carnivorous mammal. The rail is therefore unlikely to be a source of human gnathostomiasis, which is normally caused by consuming raw or undercooked infected poultry, pork, freshwater fish, or by drinking water contaminated with infected Cyclops.
on the IUCN Red List
. In most European countries, the population is either stable or decreasing slightly due to loss of habitat. The rail's range and numbers are increasing in Morocco, with breeding as far south as Oued Massa
. Little is known about the Asian range, but korejewi is a common breeder in Pakistan and Kashmir, and indicus is uncommon in Japan.
Introduced predators are a threat to vulnerable island populations. In addition to the extirpation
of the Icelandic race, mink have been responsible for marked declines in the populations of Water Rails and other ground-nesting birds in the Hebrides
, where the mainly fish-eating otter was the only native carnivore
. The mink derived from fur farm
s on Lewis, from whence they spread through Harris, North Uist
and South Uist
. Mink and ferret
eradication programmes have enabled the rail to return to islands including Lewis and Harris, and further projects are ongoing or planned on the Scottish mainland. Locally, habitat may be affected by the drainage of marshes, canalisation of water courses and urban encroachment, or by pollution.
Water Rails have been eaten by humans for thousands of years; they were eaten by the Romans, and depicted in wall paintings at Pompeii
, and consumption continued through the Middle Ages
to modern times. However, because of the bird's habitat and skulking nature, hunting appears not to be a serious threat. In Japan the Ministry of Agriculture and Forestry reported that "only about 50,000" were killed annually in the mid-20th century, although this number was thought to include several other species of wetland birds.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
of the rail family
Rallidae
The rails, or Rallidae, are a large cosmopolitan family of small to medium-sized birds. The family exhibits considerable diversity and the family also includes the crakes, coots, and gallinules...
which breeds in well-vegetated wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
s across Europe, Asia and North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
. Northern and eastern populations are migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
, but this species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
is a permanent resident in the warmer parts of its breeding range. The adult is 23–28 cm (9–11 in) long, and, like other rails, has a body that is flattened laterally to allow it easier passage through the reed bed
Reed bed
Reed beds are natural habitats found in floodplains, waterlogged depressions andestuaries. Reed beds are part of a succession from young reed colonising open water or wet ground through a gradation of increasingly dry ground...
s it inhabits. It has mainly brown upperparts and blue-grey underparts, black barring on the flanks, long toes, a short tail and a long reddish bill. The eastern subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, R. a. indicus, has distinctive markings and a call that is very different from the pig-like squeal of the western races, and is sometimes split as a separate species. Immature birds are generally similar in appearance to the adults, but the blue-grey in the plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
is replaced by buff. The downy chicks are black, as with all rails.
The Water Rail breeds in reed beds and other marshy sites with tall, dense vegetation, building its nest a little above the water level from whatever plants are available nearby. The off-white, blotched eggs are incubated
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
mainly by the female, and the precocial
Precocial
In biology, the term precocial refers to species in which the young are relatively mature and mobile from the moment of birth or hatching. The opposite developmental strategy is called "altricial," where the young are born or hatched helpless. Extremely precocial species may be called...
downy chicks hatch in 19–22 days. The female will defend her eggs and brood against intruders, or move them to another location if they are discovered. This species can breed after its first year, and it normally raises two clutches
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
in each season. Water Rails are omnivorous
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
, although they feed mainly on animals. They are territorial even after breeding, and will aggressively defend feeding areas in winter.
These rails are vulnerable to flooding or freezing conditions, loss of habitat and predation by mammals and large birds. The introduced American mink
American Mink
The American mink is a semi-aquatic species of Mustelid native to North America, though human intervention has expanded its range to many parts of Europe and South America. Because of this, it is classed as Least Concern by the IUCN. Since the extinction of the sea mink, the American mink is the...
has exterminated some island populations, but overall the species' huge range and large numbers mean that it is not considered to be threatened.
Taxonomy
The railsRallidae
The rails, or Rallidae, are a large cosmopolitan family of small to medium-sized birds. The family exhibits considerable diversity and the family also includes the crakes, coots, and gallinules...
are a bird family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
comprising nearly 150 species. Although the origins of the group are lost in antiquity, the largest number of species and the most primitive forms are found in the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
, suggesting that this family originated there. However, the genus Rallus
Rallus
Rallus is a genus of wetland birds of the rail family. Sometimes, the genera Lewinia and Gallirallus are included in it. Six of the species are found in the Americas, and the three species found in Eurasia, Africa and Madagascar are very closely related to each other, suggesting they are descended...
, the group of long-billed reed bed specialists to which the Water Rail belongs, arose in the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
. Its Old World members, the Water, African
African Rail
The African Rail is a small wetland bird of the rail family.Its breeding habitat is marshes and reedbeds across eastern and southern Africa from Ethiopia to South Africa...
and Madagascar Rail
Madagascar Rail
The Madagascar Rail is a species of bird in the Rallidae family.It is endemic to Madagascar.Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montanes, and freshwater marshes.It is threatened by habitat loss.-References:* BirdLife International...
s, form a superspecies
Superspecies
A superspecies is a group of at least two more or less distinctive species with approximately parapatric distributions. Not all species complexes, whether cryptices or ring species are superspecies, and vice versa, but many are...
, and are thought to have evolved
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
from a single invasion from across the Atlantic. Gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
tic evidence suggests that the Water Rail is the most closely related of its genus to the Pacific Gallirallus
Gallirallus
Gallirallus is a genus that contains about a dozen living species of rails that live in the Australasian-Pacific region. Many of these, including the most well-known one - the bold and inquisitive weka of New Zealand - are flightless or nearly so; others, such as the Buff-banded Rail, can go for...
rails, and is basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
to that group. The Water Rail was first described by Linnaeus in his Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
in 1758 under its current scientific name, Rallus aquaticus. The binomial name
Binomial nomenclature
Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages...
is the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
equivalent of the English "Water Rail".
The subspecies R. a. indicus has, in addition to its distinctive plumage, very different vocalisations to the other subspecies, and it was considered a separate species in early works, including the first edition (1898) of Fauna of British India, but later demoted to a subspecies by E. C. Stuart Baker
E. C. Stuart Baker
Edward Charles Stuart Baker CIE OBE FZS FLS was a British ornithologist and police officer.-Life and career:Baker was educated at Trinity College, Stratford-upon-Avon and in 1883 followed his father into the Indian Police Service. He spent most of his career in India in the Assam Police, rising to...
in the second edition (1929). It was restored as a full species, the Eastern Water Rail, R. indicus, by Pamela Rasmussen
Pamela C. Rasmussen
Professor Pamela Cecile Rasmussen is a prominent American ornithologist and expert on Asian birds. She was formerly a research associate at the Smithsonian Institution in Washington D.C., and is based at the Michigan State University...
in her Birds of South Asia
Birds of South Asia. The Ripley Guide
Birds of South Asia. The Ripley Guide by Pamela C. Rasmussen and John C. Anderton is a two-volume ornithological handbook, covering the birds of South Asia, published in 2005 by the Smithsonian Institution and Lynx Edicions...
(2005). Rasmussen, an expert on Asian birds, also renamed the other forms as the Western Water Rail. Her treatment has not otherwise been widely adopted, but is followed in Birds of Malaysia and Singapore (2010). A 2010 study of molecular phylogeny further supported the possibility of specific status for R. a. indicus, which is estimated to have diverged from the western forms around 534,000 years ago. The paper also suggested that the differences between the three other races were clinal, and that they should all be merged into R. a. aquaticus.
Fossils
The oldest known fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s of an ancestral Water Rail are bones from Carpathia
Carpathian Mountains
The Carpathian Mountains or Carpathians are a range of mountains forming an arc roughly long across Central and Eastern Europe, making them the second-longest mountain range in Europe...
dated to the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
(5.3–1.8 million years ago). By the late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, two million years ago, the fossil evidence suggests that the Water Rail was present across most of its present range. This species is surprisingly well recorded, with over 30 records from Bulgaria alone, and many others from across southern Europe. and China. A rail from Eivissa
Ibiza
Ibiza or Eivissa is a Spanish island in the Mediterranean Sea 79 km off the coast of the city of Valencia in Spain. It is the third largest of the Balearic Islands, an autonomous community of Spain. With Formentera, it is one of the two Pine Islands or Pityuses. Its largest cities are Ibiza...
, Rallus eivissensis
Ibiza Rail
The Ibiza Rail is a new species of rail, described from a late Pleistocene to Holocene cave deposit at Es Pouàs, on the island of Ibiza. Ibiza is in the Pityuses group of the Spanish Balearic Islands in the Mediterranean Sea...
, was smaller but more robust than than the Water Rail, and probably had poorer flight abilities. In the Quaternary
Quaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
, the island lacked terrestrial mammals, and this distinctive form was presumably descended from its continental relative. It became extinct at about the same time as humans arrived on the island, between 16,700 and 5,300 BC. The nominate race of Water Rail is now a very rare resident on Eivissa.
Description
The adult of the nominate subspecies is a medium-sized rail, 23–28 cm (9–11 in) long with a 38–45 cm (15–17.7 in) wingspan. Males typically weigh 114 – and females are slightly lighter at 92 –. The upperparts from the forehead to tail are olive-brown with black streaks, especially on the shoulders. The sides of the head and the underparts down to the upper belly are dark slate-blue, except for a blackish area between bill and eye, and brownish sides to the upper breast. The flanks are barred black and white, and the undertail is white with some darker streaks. The long bill and the irisIris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
are red, and the legs are flesh-brown. The sexes are similar; although the female averages slightly smaller than the male, with a more slender bill, determining sex through measurements alone is unreliable. The juvenile has a blackish crown and a white chin and throat. The underparts are buff or white with darker bars, and the flank markings are brown and buff, rather than black and white. The undertail is buff, and the eye, bill and leg colours are duller than the adult. The downy chick is all black apart from a mainly white bill. After breeding, the rail has an extensive moult, and is flightless for about three weeks. Individual adults can be identified by the markings on the undertail, which are unique to each bird. Adult males have the strongest black undertail streaks. It has been suggested that the dark barring on the undertail of this species is a compromise between the signalling function of a pure white undertail, as found in open water or gregarious species like the Common Moorhen
Common Moorhen
The Common Moorhen is a bird in the Rallidae family with an almost worldwide distribution. The North and South American Committees of the AOU and the IOC have voted on or before July 2011 to split the American forms into a new species Common Gallinule, however, no other committee has voted to...
, and the need to avoid being too conspicuous.
The Water Rail can readily be distinguished from most other reed bed rails by its white undertail and red bill; the latter is a little longer than the rest of the rail's head (55–58% of the total) and slightly down-curved. The somewhat similar Slaty-breasted Rail
Slaty-breasted Rail
The Slaty-breasted Rail is a species of rail found in the Indian Subcontinent and Southeast Asia.Breeding has been recorded from July in the foothills of the Himalayas from Dehradun in the west....
of tropical Asia has a stouter bill, a chestnut crown and white-spotted upperparts. Juvenile and freshly moulted Water Rails may show a buff undertail like Spotted Crake
Spotted Crake
The Spotted Crake is a small waterbird, of the family Rallidae.Their breeding habitat is marshes and sedge beds across temperate Europe into western Asia. They nest in a dry location in marsh vegetation, laying 6-15 eggs...
, but that species' plumage is spotted with white, and it has a much shorter, mainly yellowish bill. The range of the Water Rail does not overlap with that of any other Rallus species, but vagrants could be distinguished from their American relatives by the lack of rufous or chestnut on the closed wing. The larger African Rail
African Rail
The African Rail is a small wetland bird of the rail family.Its breeding habitat is marshes and reedbeds across eastern and southern Africa from Ethiopia to South Africa...
has unstreaked darker brown upperparts and brighter red legs and feet.
Voice
The Water Rail is a vocal species which gives its main call, known as "sharming", throughout the year. This is a series of grunts followed by a high-pitched piglet-like squeal and ending in more grunts. It is used as a territorial call, alarm and announcement. Members of a pair may call alternately, the male giving lower and slower notes than his partner. The courtship song, given by both sexes, is a tyick-tyick-tyick often ending with a trill from the female; the male may sing for hours. The flight call is a sharp whistle, and other vocalizations include a loud repeated creak given by the male when showing the nest site to the female, and a purring given by both parents when at the nest with chicks. The rails are most vocal when setting up a territory and early in the breeding season, when calling may continue at night. Chicks initially cheep weakly, but soon develop a tyk-tyk-trik begging call.The call of the subspecies R. a. indicus is quite different from that of the other forms. The courtship call, again given throughout the year, is a sharp piping kyu, longer and clearer than that of the European race. The song is a series of metallic slurred shrink, shrink notes, about two per second, and repeated after a short pause. The eastern race does not respond to recorded announcement calls of nominate R. a. aquaticus. When researchers played recordings of the Reed Warbler at night to attract that species for trapping, they found Water Rails and other wetland birds were also grounded, despite a lack of suitable habitat, suggesting that the rails and other nocturnal migrants recognised the warbler’s song and associated it with the marshy habitat in which it is usually found.
Subspecies
There are four recognised subspecies, one of which is particularly distinctive.- R. a. aquaticus (Linnaeus, 1758). This is the nominate subspecies that breeds in Europe, North Africa, Turkey, western Asia to the Caspian SeaCaspian SeaThe Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
and western Kazakhstan, and in a narrow band east to central SiberiaSiberiaSiberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
. - R. a. hibernans (SalomonsenFinn SalomonsenFinn Salomonsen was a Danish ornithologist. He is best known for his work on the birds of Greenland.His interest in Greenland began at the age of 16 when he made a trip with Lehn Schioler to the Upernavik District. He obtained a degree in zoology in 1932 and joined as a zoological assistant in the...
, 1931). The Icelandic race, which has slightly warmer brown upperparts than the nominate form. The bars of the flanks are dark brown, not black, and the bill is somewhat shorter; the grey of the underparts may have a brown tinge. - R. a. korejewi (ZarudnyNikolai ZarudnyNikolai Alekseyvich Zarudny was a Ukrainian-Russian explorer and zoologist of Ukrainian origin, who studied the fauna, especially the birds of Central Asia. He was born in Gryakovo, Ukraine . He wrote his first ornithology book in 1896 and made five expeditions in the Caspian region from 1884 and...
, 1905) (includes the dubious forms deserticolor, tsaidamensis and arjanicus). This subspecies breeds in south central Asia from southern and eastern Iran east to western China, and in the Indian subcontinent in KashmirKashmirKashmir is the northwestern region of the Indian subcontinent. Until the mid-19th century, the term Kashmir geographically denoted only the valley between the Great Himalayas and the Pir Panjal mountain range...
and LadakhLadakhLadakh is a region of Jammu and Kashmir, the northernmost state of the Republic of India. It lies between the Kunlun mountain range in the north and the main Great Himalayas to the south, inhabited by people of Indo-Aryan and Tibetan descent...
. It is slightly larger than the nominate race, with paler brown upperparts and slightly paler slate underparts. It has a weak brown stripe through the eye. - R. a. indicus (BlythEdward BlythEdward Blyth was an English zoologist and pharmacist. He was one of the founders of zoology in India....
, 1849), (includes the dubious form japonicus). Also known as the Eastern Water Rail or Brown-cheeked Rail, this distinctive race breeds in northern Mongolia, eastern Siberia, northeast China, Korea and northern Japan. It differs from the slightly smaller nominate form through its paler upperparts, brown-tinged underparts and a brown stripe through the eye. Compared to R. a. korejewi, it is darker above, has a browner breast, white on the throat and a more obvious brown eyestripe. As indicated above, it has different vocalisations to the other forms, and is sometimes given full species status, although its behaviour, nest and eggs are identical to those of the other races.
Distribution and habitat
The Water Rail breeds across temperate Eurasia from Iceland and the British Isles discontinuously to Siberia, Korea, China and northern Japan, and in suitable habitat in North Africa, Saudi Arabia and Turkey. Its distribution in Asia is poorly studied, and may be more extensive than currently known.The Icelandic population of Water Rail, R. a. hibernans, became extinct around 1965, due to loss of habitat through the draining of wetlands, and predation by introduced American mink
American Mink
The American mink is a semi-aquatic species of Mustelid native to North America, though human intervention has expanded its range to many parts of Europe and South America. Because of this, it is classed as Least Concern by the IUCN. Since the extinction of the sea mink, the American mink is the...
. Prior to its extinction, least some birds were present year-round on the island, relying on warm volcanic springs to survive through the coldest months, but this race was also found in winter in the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
and Ireland, and on passage through the Western Isles
Outer Hebrides
The Outer Hebrides also known as the Western Isles and the Long Island, is an island chain off the west coast of Scotland. The islands are geographically contiguous with Comhairle nan Eilean Siar, one of the 32 unitary council areas of Scotland...
, suggesting that the Icelandic form was a partial migrant. The nominate subspecies, R. a. aquaticus is resident in the milder south and west of its range, but migrates south from areas that are subject to harsh winters. It winters within its breeding range, and also further south in North Africa, the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
and the Caspian Sea
Caspian Sea
The Caspian Sea is the largest enclosed body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. The sea has a surface area of and a volume of...
area. The peak migration period is September to October, with most birds returning to the breeding grounds from March to mid-April. A specimen of the nominate population labelled as "Baluchistan
Balochistan
Balochistan or Baluchistan is a region which covers parts of Afghanistan, Iran and Pakistan. It can also refer to one of several modern and historical territories within that region:...
" and collected by Richard Meinertzhagen
Richard Meinertzhagen
Colonel Richard Henry Meinertzhagen CBE DSO was a British soldier, intelligence officer and ornithologist.- Background and youth :Meinertzhagen was born into a socially connected, wealthy British family...
is considered of doubtful provenance. R. a. korejewi is another partial migrant, with some of the population wintering from Iraq and eastern Saudi Arabia eastwards through Pakistan and northern India to western China.
The subspecies R. a. indicus is mainly migratory, wintering in southern Japan, eastern China and northern Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
. It is uncommon in northern parts of Bangladesh, Burma, Laos, and northern and central Thailand, and does not normally reach further south in mainland southeast Asia. Migrants have been recorded on Sri Lanka in the past, although on the Indian mainland they are found mainly in the northern regions, with a few records from as far south as Mumbai
Mumbai
Mumbai , formerly known as Bombay in English, is the capital of the Indian state of Maharashtra. It is the most populous city in India, and the fourth most populous city in the world, with a total metropolitan area population of approximately 20.5 million...
. On arrival in India, rails may be so exhausted that they can be caught by hand. The breeding birds on the Japanese island of Hokkaido
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
mostly migrate well south including to Korea but a few remain during winter in the coastal marshes of Honshu
Honshu
is the largest island of Japan. The nation's main island, it is south of Hokkaido across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyushu across the Kanmon Strait...
.
The breeding habitat of the Water Rail is permanent wetland with still or slow-moving fresh or brackish water and dense, tall vegetation, which may include common reed
Phragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...
, reedmace
Typha
Typha is a genus of about eleven species of monocotyledonous flowering plants in the family Typhaceae. The genus has a largely Northern Hemisphere distribution, but is essentially cosmopolitan, being found in a variety of wetland habitats...
, irises
Iris (plant)
Iris is a genus of 260-300species of flowering plants with showy flowers. It takes its name from the Greek word for a rainbow, referring to the wide variety of flower colors found among the many species...
, bur-reed
Sparganium
Sparganium is a genus of flowering plants, containing about 20 species in temperate regions of both the Northern and Southern Hemispheres. It was previously placed alone in the family Sparganiaceae...
or sedges
Carex
Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...
. In coastal areas, sea rush
Juncus maritimus
Juncus maritimus, known as the sea rush, is a species of rush that grows on coastlines.-External links:* on the Encyclopedia of Life...
is common in saltmarsh breeding sites, with sedges and bur-reed dominant in somewhat less saline environments. A study in The Netherlands and Spain showed that the rush provided better concealment than the other maritime plants. As elsewhere, nests were constructed from the nearest available plants. Where it occurs, saw-sedge
Cladium mariscus
Cladium mariscus is a species of flowering plant in the sedge family known by the common name Saw-sedge or Sawtooth Sedge. It is native of temperate Europe and Asia where it grows in base-rich boggy areas and lakesides. It can be up to 2.5 metres tall, and has leaves with hard serrated edges....
provides good breeding habitat, its tall (1.5 m, 5 ft) dense structure providing good cover for the nesting rails. The preferred habitat is Phragmites
Phragmites
Phragmites, the Common reed, is a large perennial grass found in wetlands throughout temperate and tropical regions of the world. Phragmites australis is sometimes regarded as the sole species of the genus Phragmites, though some botanists divide Phragmites australis into three or four species...
reedbed with the plants standing in water, with a depth of 5–30 cm (2–12 in), muddy areas for feeding and a rich diversity of invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
species. Locations with nearby willows or shrubs are favoured above large areas of uniform habitat. In addition to natural fresh or marine marshes, this rail may use gravel or clay excavations and peat workings as long as there is suitable habitat with good cover. It may be found in rice paddies or on floating islands, and it occurs in Kashmir in flooded sugarcane fields. A Finnish study showed that the main factor influencing the distribution of Water Rails was the extent of vegetation cover, with the highest densities in the most vegetated areas; the presence of other marshes nearby was also significant. However, factors such as temperature, rainfall, length of shore line and extent of peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
, important for some other marsh birds, were not statistically relevant. The areas with the highest densities of the rail also had the greatest numbers of three species considered at risk in Finland, the Great Reed Warbler
Great Reed Warbler
The Great Reed Warbler, Acrocephalus arundinaceus, is an Eurasiaan songbird in the genus Acrocephalus. It used to be placed in the "Old World warbler" assemblage, but nowadays is recognized to be part of the marsh- and tree-warbler family .-Description:This is a large thrush-sized warbler,...
, Eurasian Bittern and Marsh Harrier
Western Marsh Harrier
The Western Marsh-harrier is a mid-sized harrier, a bird of prey from temperate and subtropical western Eurasia and adjacent Africa. It is also known as the Eurasian Marsh-harrier....
. The northern limit of breeding seems to be determined by the transition from nutrient-rich wetland to poorer, more acidic water. This leads to the replacement of common reed by a more open vegetation type dominated by marsh cinquefoil, which is unsuitable for the rails.
Occasionally, more unusual locations are used. One pair in Scotland nested in the open by the side of a road, and when an English nature reserve
Nature reserve
A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...
installed nest boxes for Bearded Tits (reed "wigwam
Wigwam
A wigwam or wickiup is a domed room dwelling used by certain Native American tribes. The term wickiup is generally used to label these kinds of dwellings in American Southwest and West. Wigwam is usually applied to these structures in the American Northeast...
s" with a wooden floor), rails nested both in the boxes and under the wooden floor, in the latter case sometimes with the tits in residence above. Although mainly a lowland species, the Water Rail breeds at 1,240 m (4,070 ft) in the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
and 2,000 m (6,560 ft) in Armenia. An Italian study suggested that reed bed birds need a minimum area of wetland for breeding, which for the Water Rail is about 1 ha (2.47 acres), although the highest densities are in marshes of 10 ha (25 acres) or more.
On migration and in winter, a wider range of wet habitats may be used, including flooded thickets or bracken. Freezing condition may force birds into more open locations such as ditches, rubbish dumps and gardens, or even out onto exposed ice. A Welsh study suggested that individual winter territories overlap, with each bird using a significant proportion of the reed bed. After site desertion in freezing weather, birds return to their former range. A density of 14 birds per hectare (6.6 per acre) was recorded. Birds wintering in Iceland rely on warm geothermal
Geothermal gradient
Geothermal gradient is the rate of increasing temperature with respect to increasing depth in the Earth's interior. Away from tectonic plate boundaries, it is 25–30°C per km of depth in most of the world. Strictly speaking, geo-thermal necessarily refers to the Earth but the concept may be applied...
streams, and may access streams through tunnels under the snow. When not feeding, they may shelter in holes and crevices in the solidified lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
. This species sometimes wanders well outside its normal range and vagrants
Vagrancy (biology)
Vagrancy is a phenomenon in biology whereby individual animals appear well outside their normal range; individual animals which exhibit vagrancy are known as vagrants. The term accidental is sometimes also used...
have been found in the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...
, Mauritania, the Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
, Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
, Malaysia and Vietnam.
Behaviour
This rail is a skulking species, its streaked plumage making it difficult to see in its wetland habitat. Its laterally compressed body allows it to slip though the densest vegetation, and it will "freeze" if surprised in the open. It walks with a high-stepping gait, although it adopts a crouch when it runs for cover. It swims, when necessary, with the jerky motion typical of rails, and it flies short distances low over the reeds with its long legs dangling. Although their flight looks weak, Water Rails are capable of long sustained flights during their nocturnal migrations, and are sometimes killed in collisions with lighthouses or wires. British-ringed birds have been recovered from as far away as Poland, Czechoslovakia and Sweden.This species defends its breeding and wintering territories. Birds will charge each other with neck outstretched when breeding, sometimes both members of a pair attacking together. Large strongly-marked males are dominant in winter, when the direct aggression is replaced by sharming while standing upright on tip-toe, head jerking and bill thrusting.
Breeding
The Water Rail is monogamousMonogamy
Monogamy /Gr. μονός+γάμος - one+marriage/ a form of marriage in which an individual has only one spouse at any one time. In current usage monogamy often refers to having one sexual partner irrespective of marriage or reproduction...
and highly territorial when breeding. The birds pair off after arriving at their nesting areas, or possibly even before spring migration. In large wetlands with good conditions birds may nest 20–50 m (22–55 yd) apart. Territories vary in size, but 300 m2 (360 yd2) is typical. The pair give courting and contact calls throughout the breeding season. The male selects the nest site which he shows to the female while posturing with raised back feathers, wings arched over his back, tail spread and bill pointed vertically downwards. This display is accompanied by a loud call. Before mating, he raises his wings and tail, and bows with his bill touching his breast. The male feeds the female during courtship, and, when incubating, she may leave the nest to display to the male, walking round him, calling softly, rubbing her bill against his and taking short runs to and from him.
The nest is made from whatever wetland vegetation is available and built mostly by the male, usually in a single day. It is raised 15 cm (6 in) or more above the level of the marsh, and is sometimes constructed on clumps of roots, tree stumps or similar support. It may be built up higher if the marsh waters start to rise. The nest is 13–16 cm (5–7 in) across and about 7 cm (3 in high). It is well hidden and approached cautiously by narrow tracks. The average weight of wind-dried nests of R. a. indicus in Japan was 95 g (3.4 oz).
The typical clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
is 6–11 eggs across most of the range, but appears to be smaller (5–8) in Kashmir at around 1,500 m (4,900 ft) altitude. Laying dates vary with location, from late March in western Europe and North Africa, to late May in Kashmir and June in Iceland. The clutch size may be smaller early or late in the breeding season. The breeding season can be extended by replacement and second clutches. The eggs are blunt and oval, smooth and slightly glossy; the colour varies from off-white to pink-buff, with reddish-brown blotches mainly at the broader end that sometimes merging into a single patch. Variation in egg size across the four subspecies is much less than differences between individual eggs; the average size of the eggs of the nominate subspecies, 36 × 26 mm, (1.4 × 1.0 in) is therefore typical for the species as a whole. The eggs weigh about 13 g, (0.46 oz), of which 7% is shell.
Both parents incubate the eggs, although the female takes the larger share of this duty. The eggs are incubated for 19–22 days to hatching, with at least 87% success, and the precocial
Precocial
In biology, the term precocial refers to species in which the young are relatively mature and mobile from the moment of birth or hatching. The opposite developmental strategy is called "altricial," where the young are born or hatched helpless. Extremely precocial species may be called...
, downy young fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
in another 20–30 days. Food is brought to the nest by the other adult and passed to the sitting parent who feeds the chicks, although they also find some of their own food after about five days. After fledging, the young birds fend for themselves. They can fly when aged 7–9 weeks. If a nest appears to have been discovered, the female may carry the chicks or eggs one by one to another location; the eggs are carried in the bill, but small chicks may be tucked under the wing. Sitting birds may stay on the eggs even when approached closely, or attack the intruder, or feign injury as a distraction. The Water Rail can breed after its first year, and it normally raises two broods.
Average survival after fledging has been estimated as between 17 and 20 months, with an annual survival rate slightly less than 50% per year for the first three years, and somewhat higher thereafter. The maximum recorded age is 8 years 10 months.
Feeding
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
, although they mainly feed on animals. These include leech
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
es, worm
Worm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
s, gastropods
Gastropoda
The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...
, small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, spiders, and a wide range of both terrestrial and aquatic insects and their larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e. Small vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s such as amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s, fish, birds and mammals may be killed or eaten as carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
. Vertebrates are impaled with a strike of the bill which breaks the prey's spinal cord. Plant food, which is consumed more in autumn and winter, includes the buds, seeds, flowers, shoots and seeds of water plants, berries and fruit. In south Asia, paddy (harvested rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
kernel
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s) may sometimes be eaten. The young rails are fed mainly on insects and spiders. Food obtained on land or from mud is normally washed in water before it is eaten. After rain, rails may probe soft ground for earthworms. This species will occasionally feed in the open even when not forced to do so by cold weather; Edmund Meade-Waldo
Edmund Meade-Waldo
Edmund Gustavus Bloomfield Meade-Waldo was an English ornithologist and conservationist.Meade-Waldo was born in Hever Castle and educated at Eton College and Cambridge University. He collected birds in the Atlas Mountains of Morocco, the Canary Islands and Spain, the presumably-extinct Canarian...
described seven rails feeding in an open meadow. Despite its skulking nature, the water Rail appears to thrive in captivity when fed on animal food such as raw meat or earthworms; one individual was taught to jump for worms suspended from a fishing rod.
Water Rails follow definite routes when feeding, frequently returning to good hunting areas. These rails are versatile and opportunist foragers. They will jump to take insects from plants, climb to find berries, or dislodge apples from trees so they can be eaten on the ground. They will kill birds by impaling or drowning them, particularly if the bird's ability to escape is restricted. They have been recorded as killing a European Greenfinch
European Greenfinch
The European Greenfinch, or just Greenfinch, Carduelis chloris, is a small passerine bird in the finch family Fringillidae. The genus Carduelis might be split up and in this case, the greenfinches would be separated in their old genus Chloris again.This bird is widespread throughout Europe, north...
and a King Quail in an aviary
Aviary
An aviary is a large enclosure for confining birds. Unlike cages, aviaries allow birds a larger living space where they can fly; hence, aviaries are also sometimes known as flight cages...
, and small birds trapped in bird ringers'
Bird ringing
Bird ringing or bird banding is a technique used in the study of wild birds, by attaching a small, individually numbered, metal or plastic tag to their legs or wings, so that various aspects of the bird's life can be studied by the ability to re-find the same individual later...
mist net
Mist net
Mist nets are used by ornithologists and bat biologists to capture wild birds and bats for banding or other research projects. Mist nets are typically made of nylon mesh suspended between two poles, resembling an oversized volleyball net. When properly deployed, the nets are virtually invisible...
s. One bird killed Twite
Twite
The Twite is a small passerine bird in the finch family Fringillidae.The Twite is a small finch, similar in size and shape to a Linnet. Birds of the subspecies flavirostris are long, and those of the subspecies altaica are long. It lacks the red head patch and breast shown by the Linnet and the...
caught with it in a Heligoland trap
Heligoland trap
A Heligoland trap is a large, building-sized, funnel-shaped, rigid structure of wire mesh or netting used to trap birds, so that they can be banded or otherwise studied by ornithologists....
. They are also nest predators, particularly of small birds that nest in reeds such as the Great Reed Warbler
Great Reed Warbler
The Great Reed Warbler, Acrocephalus arundinaceus, is an Eurasiaan songbird in the genus Acrocephalus. It used to be placed in the "Old World warbler" assemblage, but nowadays is recognized to be part of the marsh- and tree-warbler family .-Description:This is a large thrush-sized warbler,...
. Water Rails may defend a winter feeding territory, although this is smaller than when breeding, with individuals perhaps less than 10 m (11 yd) apart; favoured sites may hold hundreds of birds. Aggressive behaviour outside the breeding season may extend to attacks on other marsh rails such as Spotted
Spotted Crake
The Spotted Crake is a small waterbird, of the family Rallidae.Their breeding habitat is marshes and sedge beds across temperate Europe into western Asia. They nest in a dry location in marsh vegetation, laying 6-15 eggs...
and Baillon's Crake
Baillon's Crake
The Baillon's Crake is a very small waterbird of the family Rallidae.-Distribution:Their breeding habitat is sedge beds in Europe, mainly in the east, and across Asia. They used to breed in Great Britain up to the mid-19th century, but the western European population declined through drainage....
.
Predators and parasites
European Otter
The European Otter , also known as the Eurasian otter, Eurasian river otter, common otter and Old World otter, is a European and Asian member of the Lutrinae or otter subfamily, and is typical of freshwater otters....
will also eat rails and other water birds. The Eurasian Bittern, another reed bed bird, will consume rails, as will Grey Heron
Grey Heron
The Grey Heron , is a wading bird of the heron family Ardeidae, native throughout temperate Europe and Asia and also parts of Africa. It is resident in the milder south and west, but many birds retreat in winter from the ice in colder regions...
s. Water Rails are particularly vulnerable to the heron when forced out of the cover of the reeds by very high tides. Wetland-hunting harriers
Harrier (bird)
A harrier is any of the several species of diurnal hawks forming the Circinae sub-family of the Accipitridae family of birds of prey. Harriers characteristically hunt by flying low over open ground, feeding on small mammals, reptiles, or birds....
are predictable predators, but more unusually, the rail has also been recorded as a prey item of the Tawny Owl
Tawny Owl
The Tawny Owl or Brown Owl is a stocky, medium-sized owl commonly found in woodlands across much of Eurasia. Its underparts are pale with dark streaks, and the upperparts are either brown or grey. Several of the eleven recognised subspecies have both variants...
, Short-eared Owl
Short-eared Owl
The Short-eared Owl is a species of typical owl . In Scotland this species of owl is often referred to as a cataface, grass owl or short-horned hootlet. Owls belonging to genus Asio are known as the eared owls, as they have tufts of feathers resembling mammalian ears. These "ear" tufts may or may...
, Eurasian Eagle-owl, Greater Spotted Eagle
Greater Spotted Eagle
The Greater Spotted Eagle , occasionally just called the spotted eagle, is a large bird of prey. Like all typical eagles, it belongs to the family Accipitridae...
, Common Kestrel
Common Kestrel
The Common Kestrel is a bird of prey species belonging to the kestrel group of the falcon family Falconidae. It is also known as the European Kestrel, Eurasian Kestrel, or Old World Kestrel. In Britain, where no other brown falcon occurs, it is generally just called "the kestrel".This species...
, and night-hunting Peregrine Falcon
Peregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...
s.
Parasites include the sucking lice
Sucking louse
Sucking lice have around 500 species and represent the smaller of the two traditional suborders of lice. As opposed to the paraphyletic chewing lice, which are now divided among three suborders, the sucking lice are monophyletic.The Anoplura are all blood-feeding ectoparasites of mammals...
Nirmus cuspidiculus and Pediculus ralli, the tick
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
Ixodes frontalis, and the louse fly
Hippoboscidae
Hippoboscidae, the louse flies or keds are obligate parasites of mammals and birds. In this family there are winged species which can fly at least reasonably well, as well as others with vestigial or no wings which are flightless and highly apomorphic...
Ornithomyia avicularia. The Water Rail can be infected by the avian influenza virus and the bacterium Borrelia burgdorferi
Borrelia burgdorferi
Borrelia burgdorferi is a species of Gram negative bacteria of the spirochete class of the genus Borrelia. B. burgdorferi is predominant in North America, but also exists in Europe, and is the agent of Lyme disease....
, carried by Ixodes
Ixodes
Ixodes is a genus of hard-bodied ticks . It includes important disease vectors of animals and humans . Some ticks in this genus may transmit the pathogenic bacterium Borrelia burgdorferi responsible for causing Lyme disease...
ticks, which is also a human pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
causing Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
. Three lice
Louse
Lice is the common name for over 3,000 species of wingless insects of the order Phthiraptera; three of which are classified as human disease agents...
, Fulicoffula rallina, Pseudomenopon scopulacorne and Rallicola cuspidatus discovered on dead Water Rails in 2005 on the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
were all species that had not been found on the archipelago
Archipelago
An archipelago , sometimes called an island group, is a chain or cluster of islands. The word archipelago is derived from the Greek ἄρχι- – arkhi- and πέλαγος – pélagos through the Italian arcipelago...
previously. The parasitic flatworm
Cyclocoelidae
The Cyclocoelidae are a family of parasitic flatworms. They are placed in the monotypic suborder Cyclocoelata of the order Echinostomida....
Ophthalmophagus nasciola was found in one rail's nasal sinus
Sinus (anatomy)
Sinus is Latin for "bay", "pocket", "curve", or "bosom". In anatomy, the term is used in various contexts.A sinus is a sack or cavity in any organ or tissue, or an abnormal cavity or passage caused by the destruction of tissue...
, and at least three species of feather mite
Feather mite
Feather mites are the members of diverse mite superfamilies:* superorder Acariformes** Psoroptidia*** Analgoidea*** Freyanoidea*** Pterolichoidea* superorder Parasitiformes** DermanyssoideaThey are ectoparasites on birds, hence the common name....
have been detected on the plumage. The louse Philopterus ralli and the nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
Strongyloides avium have been found on the subspecies R. a. indicus. The eastern subspecies is also one of the many intermediate hosts of another nematode, Gnathostoma spinigerum
Gnathostoma spinigerum
Gnathostoma spinigerum is a parasitic nematode that causes gnathostomiasis in humans, also known as its clinical manifestations are creeping eruption, larva migrans, Yangtze edema, Choko-Fuschu Tua chid and wandering swelling. Gnathostomiasis in animals can be serious, and even fatal...
, which causes human gnathostomiasis
Gnathostomiasis
Gnathostomiasis is the human infection by the nematode Gnathostoma spinigerum and/or Gnathostoma hispidum, which infects vertebrates.-Synonyms:...
, a disease found in Thailand, Japan and other parts of Southeast Asia. The nematode's first-stage hosts are copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s of the genus Cyclops
Cyclops (genus)
Cyclops is one of the most common genera of freshwater copepods, comprising over 400 species . The name Cyclops comes from the Cyclops of Greek mythology which shares the quality of having a single large eye, which may be either red or black in Cyclops.Cyclops individuals may range from...
, which are consumed directly or indirectly by a wide variety of vertebrates before maturing in the third and final host, a carnivorous mammal. The rail is therefore unlikely to be a source of human gnathostomiasis, which is normally caused by consuming raw or undercooked infected poultry, pork, freshwater fish, or by drinking water contaminated with infected Cyclops.
Status
The Water Rail's numbers are declining, but it has a large population of 100,000–1,000,000 adults and a huge breeding range estimated at 15,600,000 km2 (6,000,000 mi2); it is therefore classed as Least ConcernLeast Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
. In most European countries, the population is either stable or decreasing slightly due to loss of habitat. The rail's range and numbers are increasing in Morocco, with breeding as far south as Oued Massa
Souss-Massa National Park
The Souss-Massa National Park is a 33,800 hectare national park on the Atlantic coast of Morocco which was created in 1991. It lies between Agadir to the north and Sidi Ifni to the south and its centre is at 9o 40' West 30° 5' north...
. Little is known about the Asian range, but korejewi is a common breeder in Pakistan and Kashmir, and indicus is uncommon in Japan.
Introduced predators are a threat to vulnerable island populations. In addition to the extirpation
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
of the Icelandic race, mink have been responsible for marked declines in the populations of Water Rails and other ground-nesting birds in the Hebrides
Hebrides
The Hebrides comprise a widespread and diverse archipelago off the west coast of Scotland. There are two main groups: the Inner and Outer Hebrides. These islands have a long history of occupation dating back to the Mesolithic and the culture of the residents has been affected by the successive...
, where the mainly fish-eating otter was the only native carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
. The mink derived from fur farm
Fur farming
Fur farming is the practice of breeding or raising certain types of animals for their fur.Fur used from wild caught animals is not farmed, and is instead known as 'free range fur' because the animals have lived their lives free and natural in the wild....
s on Lewis, from whence they spread through Harris, North Uist
North Uist
North Uist is an island and community in the Outer Hebrides of Scotland.-Geography:North Uist is the tenth largest Scottish island and the thirteenth largest island surrounding Great Britain. It has an area of , slightly smaller than South Uist. North Uist is connected by causeways to Benbecula...
and South Uist
South Uist
South Uist is an island of the Outer Hebrides in Scotland. In the 2001 census it had a usually resident population of 1,818. There is a nature reserve and a number of sites of archaeological interest, including the only location in Great Britain where prehistoric mummies have been found. The...
. Mink and ferret
Ferret
The ferret is a domesticated mammal of the type Mustela putorius furo. Ferrets are sexually dimorphic predators with males being substantially larger than females. They typically have brown, black, white, or mixed fur...
eradication programmes have enabled the rail to return to islands including Lewis and Harris, and further projects are ongoing or planned on the Scottish mainland. Locally, habitat may be affected by the drainage of marshes, canalisation of water courses and urban encroachment, or by pollution.
Water Rails have been eaten by humans for thousands of years; they were eaten by the Romans, and depicted in wall paintings at Pompeii
Pompeii
The city of Pompeii is a partially buried Roman town-city near modern Naples in the Italian region of Campania, in the territory of the comune of Pompei. Along with Herculaneum, Pompeii was destroyed and completely buried during a long catastrophic eruption of the volcano Mount Vesuvius spanning...
, and consumption continued through the Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
to modern times. However, because of the bird's habitat and skulking nature, hunting appears not to be a serious threat. In Japan the Ministry of Agriculture and Forestry reported that "only about 50,000" were killed annually in the mid-20th century, although this number was thought to include several other species of wetland birds.