White-eyed River Martin
Encyclopedia
The White-eyed River Martin (Pseudochelidon sirintarae, sometimes Eurochelidon sirintarae) is a passerine
bird
, one of only two members of the river martin
subfamily of the swallow
family Hirundinidae. It is known only from a single wintering site in Thailand
, and may be extinct since it has not been seen since 1980.
The adult White-eyed River Martin is a medium-sized swallow, with mainly glossy greenish-black plumage, a white rump, and a tail which has two elongated slender central tail feathers with long narrow racquets at the tips. It has a white eye and a broad, bright greenish-yellow bill. The sexes are similar, but the juvenile lacks the tail racquets and is generally browner than the adult. Little is known of the behaviour or breeding habitat of this species, although like other swallows it feeds on insects caught in flight, and roosts in reedbeds in winter.
As a Thai endemic, this bird was featured on a 75 satang
postage stamp
in 1975 as one of a set of four depicting Thai birds, and on a 1974 5,000 baht
conservation issue gold
coin
.
subfamily Pseudochelidoninae, the other being the African River Martin
(Pseudochelidon eurystomina) of the Congo basin in Africa
. These two species possess a number of distinctive features which mark them out from other swallows and martins, including their robust legs and feet, and stout bill.
The extent of their differences from other swallows and the wide geographical separation of these two martins suggest that they are relict
populations of a group of species that diverged from the main swallow lineage early in its evolution
.
The genus name Pseudochelidon (Hartlaub
, 1861) comes from the Ancient Greek prefix ψευδο/pseudo "false" and χελιδον/chelidôn, "swallow", and the species name commemorates Princess Maha Chakri Sirindhorn of the Kingdom of Thailand
.
The African and Asian Pseudochelidon species differ markedly in the size of their bills
and eyes, suggesting that they have different feeding ecologies
, with the White-eyed River Martin probably being able to take much larger prey. The Thai species also has a swollen, hard gape
(fleshy interior of the bill) unlike the soft, more fleshy, and much less prominent gape of African River Martin.
It was proposed in 1972 that the White-eyed River Martin was sufficiently different from the African species to be placed in a separate monotypic genus Eurochelidon, but this was not subsequently widely adopted by other authors; however, BirdLife International
now uses Eurochelidon.
ornithologist
Kitti Thonglongya
, who obtained nine specimens netted by professional bird-hunters as part of a migratory bird survey at a night-time roost at Thailand's largest freshwater lake, Bueng Boraphet
in Nakhon Sawan Province
.
The species has only been seen at that site, always between the months of November and February, and the wintering habitat is assumed to be in the vicinity of open fresh water for feeding, with reedbeds for the night-time roost. The White-eyed River Martin may be migratory
, but its breeding grounds and habitat are unknown, although river valleys in Northern Thailand or southwestern China
are possibilities; however, a claimed depiction of this species in a Chinese scroll painting is more likely to show Oriental Pratincole
s (Glareola maldivarum). Cambodia
and Myanmar
have also been suggested as possible refuges for the species, but doubts have been cast on whether it is migratory at all.
If the breeding habitat resembles that of the African River Martin, it is likely to be the forested valleys of large rivers; these can provide sandbars and islands for nesting, and woodland over which the birds can catch insect prey.
The iris
and eyelid are white, giving the appearance of a white eye ring, and the bill is broad, bright greenish-yellow with a black hooked tip to the upper mandible
. The large, strong feet and legs are flesh-coloured. This species is silent when wintering, and its breeding vocalisations are unknown.
The sexes are similar, but the juvenile lacks the tail racquets, has a brown head and chin, and is generally browner than the adult. Juveniles taken in January and February were moult
ing their body feathers.
Since its breeding grounds are undiscovered, nothing is known about the White-eyed River Martin's breeding biology, although it is suggested that it may nest in burrows in river sandbars, probably in April or May before the monsoon
rain raises water levels. However, distinct differences in foot and toe morphology suggest that it might not burrow. In winter, it roosts with Barn Swallow
s in reedbeds.
Like other swallows, the White-eyed River Martin feeds on insect
s, including beetle
s, which are caught on the wing. Given its size and unusual mouth structure, it may well take larger insects than other swallows. This species is described as graceful and buoyant in flight, and, like its African relative, appears reluctant to use perches, behaviour that, together with its unusual toe-shape and the fact that mud was found on the toes of one of the first specimens, suggest that this species may be relatively terrestrial.
Pamela C. Rasmussen
suggested that, given its unusually large eyes, the species might be nocturnal or at least crepuscular
, a factor that could make it highly cryptic and thus partly explain how it remained undetected for so long. Although the fact that the first specimens were supposedly collected roosting at night in reedbeds might be a contraindication, it is possible that the birds might not have been caught at the roost, or they might be crepuscular, or they might be capable of both diurnal and nocturnal behaviour, depending on season or circumstance.
, which is the highest risk category assigned by the International Union for the Conservation of Nature and Natural Resources (IUCN) for wild species. The designation means that a species' numbers have decreased, or will decrease, by 80% within three generations. The IUCN does not consider a species extinct until extensive targeted surveys have been conducted, but the White-eyed River Martin may well no longer exist in the wild.
Despite legal protection under Appendix 1 (the highest category) of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreement, it was captured by locals along with other swallow
s for sale as food or for release by devout Buddhists, and following its discovery by ornithologists, trappers were reported to have caught as many as 120 and sold them to the director of the Nakhon Sawan Fisheries Station who was, of course, unable to keep them alive in captivity. The small population may therefore have become non-viable. However, a possible sighting was made in Cambodia
in 2004.
There has been a drastic decline in the Beung Boraphet swallow population from the hundreds of thousands reported around 1970 to maximum counts of 8,000 made in the winter of 1980-1981, although it is not certain if this represents a real decline or a shift in site in response to persecution. Other potential causes for the species' decline include the disturbance of riverine sand bars, the construction of dams which flood the area upstream and alter the downstream hydrology, deforestation, and increasing conversion of its habitat to agriculture
. Very few swallows now roost in the Beung Boraphet reedbeds, preferring sugarcane
plantations, and despite searching the White-eyed River Martin has not been found in other nearby large swallow roosts.
Bueng Boraphet has been declared a Non-Hunting Area in an effort to protect the species, but surveys to find this martin have been unsuccessful, including several at Bueng Boraphet, a 1969 survey of the Nan Yom and Wang River
s of northern Thailand, and a 1996 survey of rivers in northern Laos
.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
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...
, one of only two members of the river martin
River martin
The river martins form a distinctive subfamily Pseudochelidoninae within the swallow and martin bird family Hirundinidae. The two species are the African River Martin Pseudochelidon eurystomina, found in the Congo and Gabon, and the White-eyed River Martin Pseudochelidon sirintarae, known only from...
subfamily of the swallow
Swallow
The swallows and martins are a group of passerine birds in the family Hirundinidae which are characterised by their adaptation to aerial feeding...
family Hirundinidae. It is known only from a single wintering site in Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, and may be extinct since it has not been seen since 1980.
The adult White-eyed River Martin is a medium-sized swallow, with mainly glossy greenish-black plumage, a white rump, and a tail which has two elongated slender central tail feathers with long narrow racquets at the tips. It has a white eye and a broad, bright greenish-yellow bill. The sexes are similar, but the juvenile lacks the tail racquets and is generally browner than the adult. Little is known of the behaviour or breeding habitat of this species, although like other swallows it feeds on insects caught in flight, and roosts in reedbeds in winter.
As a Thai endemic, this bird was featured on a 75 satang
Thai baht
The baht is the currency of Thailand. It is subdivided into 100 satang . The issuance of currency is the responsibility of the Bank of Thailand.-History:The baht, like the pound, originated from a traditional unit of mass...
postage stamp
Postage stamp
A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...
in 1975 as one of a set of four depicting Thai birds, and on a 1974 5,000 baht
Thai baht
The baht is the currency of Thailand. It is subdivided into 100 satang . The issuance of currency is the responsibility of the Bank of Thailand.-History:The baht, like the pound, originated from a traditional unit of mass...
conservation issue gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
coin
Coin
A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory....
.
Taxonomy
The White-eyed River Martin is one of two members of the river martinRiver martin
The river martins form a distinctive subfamily Pseudochelidoninae within the swallow and martin bird family Hirundinidae. The two species are the African River Martin Pseudochelidon eurystomina, found in the Congo and Gabon, and the White-eyed River Martin Pseudochelidon sirintarae, known only from...
subfamily Pseudochelidoninae, the other being the African River Martin
African River Martin
The African River Martin is a passerine bird, one of two members of the river martin subfamily of the swallow family Hirundinidae. It is a medium-sized, mainly black-plumaged species with red eyes, a broad orange-red bill and a square tail...
(Pseudochelidon eurystomina) of the Congo basin in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. These two species possess a number of distinctive features which mark them out from other swallows and martins, including their robust legs and feet, and stout bill.
The extent of their differences from other swallows and the wide geographical separation of these two martins suggest that they are relict
Relict
A relict is a surviving remnant of a natural phenomenon.* In biology a relict is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas....
populations of a group of species that diverged from the main swallow lineage early in its evolution
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...
.
The genus name Pseudochelidon (Hartlaub
Gustav Hartlaub
Karel Johan Gustav Hartlaub was a German physician and ornithologist.Hartlaub was born in Bremen, and studied at Bonn and Berlin before graduating in medicine at Göttingen. In 1840, he began to study and collect exotic birds, which he donated to the Bremen Natural History Museum. He described some...
, 1861) comes from the Ancient Greek prefix ψευδο/pseudo "false" and χελιδον/chelidôn, "swallow", and the species name commemorates Princess Maha Chakri Sirindhorn of the Kingdom of Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
.
The African and Asian Pseudochelidon species differ markedly in the size of their bills
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
and eyes, suggesting that they have different feeding ecologies
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
, with the White-eyed River Martin probably being able to take much larger prey. The Thai species also has a swollen, hard gape
Gape
In bird anatomy, the gape is the interior of the open mouth of a bird and the gape flange is the region where the two mandibles join together, at the base of the beak...
(fleshy interior of the bill) unlike the soft, more fleshy, and much less prominent gape of African River Martin.
It was proposed in 1972 that the White-eyed River Martin was sufficiently different from the African species to be placed in a separate monotypic genus Eurochelidon, but this was not subsequently widely adopted by other authors; however, BirdLife International
BirdLife International
BirdLife International is a global Partnership of conservation organisations that strives to conserve birds, their habitats and global biodiversity, working with people towards sustainability in the use of natural resources...
now uses Eurochelidon.
Distribution and habitat
The White-eyed River Martin was discovered as recently as 1968 by ThaiThailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
ornithologist
Ornithology
Ornithology is a branch of zoology that concerns the study of birds. Several aspects of ornithology differ from related disciplines, due partly to the high visibility and the aesthetic appeal of birds...
Kitti Thonglongya
Kitti Thonglongya
Kitti Thonglongya was an eminent Thai ornithologist and mammalogist. He is probably best known for two discoveries of endangered species.-Life:...
, who obtained nine specimens netted by professional bird-hunters as part of a migratory bird survey at a night-time roost at Thailand's largest freshwater lake, Bueng Boraphet
Bueng Boraphet
Bueng Boraphet is the largest freshwater swamp and lake in central Thailand. It covers an area of 224 km² east of Nakhon Sawan, south of the Nan River close to its confluence with the Ping River....
in Nakhon Sawan Province
Nakhon Sawan Province
Nakhon Sawan is one of the provinces of Thailand. Neighboring provinces are Kamphaeng Phet, Phichit, Phetchabun, Lop Buri, Sing Buri, Chai Nat, Uthai Thani and Tak.- Etymology :...
.
The species has only been seen at that site, always between the months of November and February, and the wintering habitat is assumed to be in the vicinity of open fresh water for feeding, with reedbeds for the night-time roost. The White-eyed River Martin may be 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 its breeding grounds and habitat are unknown, although river valleys in Northern Thailand or southwestern China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
are possibilities; however, a claimed depiction of this species in a Chinese scroll painting is more likely to show Oriental Pratincole
Oriental Pratincole
The Oriental Pratincole , also known as the Grasshopper-Bird or Swallow-Plover is a wader in the pratincole family, Glareolidae....
s (Glareola maldivarum). Cambodia
Cambodia
Cambodia , officially known as the Kingdom of Cambodia, is a country located in the southern portion of the Indochina Peninsula in Southeast Asia...
and Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
have also been suggested as possible refuges for the species, but doubts have been cast on whether it is migratory at all.
If the breeding habitat resembles that of the African River Martin, it is likely to be the forested valleys of large rivers; these can provide sandbars and islands for nesting, and woodland over which the birds can catch insect prey.
Description
The adult White-eyed River Martin is a medium-sized swallow, 18 centimetres (7 in) long and mainly black with a silky blue-green gloss and a white rump. The back is green-glossed black, and is separated from the similarly coloured upper tail by a narrow bright white rump band. The head is darker than the back, with a velvet-black chin leading to blue-green glossed black underparts. The wings are black, and the tail is green-glossed black with two elongated slender central tail feathers, up to 9 centimetres (3.5 in) long expanded slightly at the tips to give long narrow racquets.The iris
Iris (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...
and eyelid are white, giving the appearance of a white eye ring, and the bill is broad, bright greenish-yellow with a black hooked tip to the upper mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
. The large, strong feet and legs are flesh-coloured. This species is silent when wintering, and its breeding vocalisations are unknown.
The sexes are similar, but the juvenile lacks the tail racquets, has a brown head and chin, and is generally browner than the adult. Juveniles taken in January and February were moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
ing their body feathers.
Behaviour
Since its breeding grounds are undiscovered, nothing is known about the White-eyed River Martin's breeding biology, although it is suggested that it may nest in burrows in river sandbars, probably in April or May before the monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
rain raises water levels. However, distinct differences in foot and toe morphology suggest that it might not burrow. In winter, it roosts with Barn Swallow
Barn Swallow
The Barn Swallow is the most widespread species of swallow in the world. It is a distinctive passerine bird with blue upperparts, a long, deeply forked tail and curved, pointed wings. It is found in Europe, Asia, Africa and the Americas...
s in reedbeds.
Like other swallows, the White-eyed River Martin feeds on insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, including beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s, which are caught on the wing. Given its size and unusual mouth structure, it may well take larger insects than other swallows. This species is described as graceful and buoyant in flight, and, like its African relative, appears reluctant to use perches, behaviour that, together with its unusual toe-shape and the fact that mud was found on the toes of one of the first specimens, suggest that this species may be relatively terrestrial.
Pamela C. 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...
suggested that, given its unusually large eyes, the species might be nocturnal or at least crepuscular
Crepuscular
Crepuscular animals are those that are active primarily during twilight, that is during dawn and dusk. The word is derived from the Latin word crepusculum, meaning "twilight." Crepuscular is, thus, in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be active on a bright...
, a factor that could make it highly cryptic and thus partly explain how it remained undetected for so long. Although the fact that the first specimens were supposedly collected roosting at night in reedbeds might be a contraindication, it is possible that the birds might not have been caught at the roost, or they might be crepuscular, or they might be capable of both diurnal and nocturnal behaviour, depending on season or circumstance.
Status
The White-eyed River Martin was seen in Thailand in 1972, 1977 and 1980, but not definitely since, though there is an unconfirmed sighting from Thailand from 1986. It is classified as critically endangeredCritically endangered
Version 2010.3 of the IUCN Red List of Threatened Species identified 3744 Critically Endangered species, subspecies and varieties, stocks and subpopulations.Critically Endangered by kingdom:*1993 Animalia*2 Fungi*1745 Plantae*4 Protista-References:...
, which is the highest risk category assigned by the International Union for the Conservation of Nature and Natural Resources (IUCN) for wild species. The designation means that a species' numbers have decreased, or will decrease, by 80% within three generations. The IUCN does not consider a species extinct until extensive targeted surveys have been conducted, but the White-eyed River Martin may well no longer exist in the wild.
Despite legal protection under Appendix 1 (the highest category) of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreement, it was captured by locals along with other swallow
Swallow
The swallows and martins are a group of passerine birds in the family Hirundinidae which are characterised by their adaptation to aerial feeding...
s for sale as food or for release by devout Buddhists, and following its discovery by ornithologists, trappers were reported to have caught as many as 120 and sold them to the director of the Nakhon Sawan Fisheries Station who was, of course, unable to keep them alive in captivity. The small population may therefore have become non-viable. However, a possible sighting was made in Cambodia
Cambodia
Cambodia , officially known as the Kingdom of Cambodia, is a country located in the southern portion of the Indochina Peninsula in Southeast Asia...
in 2004.
There has been a drastic decline in the Beung Boraphet swallow population from the hundreds of thousands reported around 1970 to maximum counts of 8,000 made in the winter of 1980-1981, although it is not certain if this represents a real decline or a shift in site in response to persecution. Other potential causes for the species' decline include the disturbance of riverine sand bars, the construction of dams which flood the area upstream and alter the downstream hydrology, deforestation, and increasing conversion of its habitat to agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
. Very few swallows now roost in the Beung Boraphet reedbeds, preferring sugarcane
Sugarcane
Sugarcane refers to any of six to 37 species of tall perennial grasses of the genus Saccharum . Native to the warm temperate to tropical regions of South Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six metres tall...
plantations, and despite searching the White-eyed River Martin has not been found in other nearby large swallow roosts.
Bueng Boraphet has been declared a Non-Hunting Area in an effort to protect the species, but surveys to find this martin have been unsuccessful, including several at Bueng Boraphet, a 1969 survey of the Nan Yom and Wang River
Wang River
The Wang River is a river in northern Thailand.-Geography:The Wang River is altogether 335nsnp;km long. Its waters flow from north to south. One of the principal settlements along the river is Lampang, which is situated on the north bank of a curve in the river. From Lampang, the river extends...
s of northern Thailand, and a 1996 survey of rivers in northern Laos
Laos
Laos Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ Sathalanalat Paxathipatai Paxaxon Lao, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south and Thailand to the west...
.