96-660: P. eurystomina P. sirintarae 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 one site in Thailand. These are medium-sized, largely black swallows that have
192-402: A 1.5 cm (0.59 in) long tarsus , red eyes, pink eye-rings, and a broad orange-red bill. The wing length averages 14 cm (5.5 in). The sexes are similar in appearance. There are many bird species in which there is sexual dichromatism that is not apparent to the human eye, but spectroscopic analysis of this martin's head feathers suggests that the colour differences between
288-430: A 1988 study on house martins . Swallows are excellent flyers and use these skills to feed and attract mates. Some species, such as the mangrove swallow , are territorial , whereas others are not and simply defend their nesting sites. In general, the male selects a nest site, and then attracts a female using song and flight and (dependent on the species) guards his territory. The size of the territory varies depending on
384-643: A 1996 survey of rivers in northern Laos . A possible unverified sighting was reported in 2004. The total population size of the African river martin is unknown. In the late 1980s, it appeared to be common, if local, and large numbers were seen on migration in Gabon. However, it is particularly poorly known in the Democratic Republic of the Congo (DRC), and it is unclear if there is any relationship between
480-443: A distinct clade from the typical swallows in the subfamily Hirundininae. The two river martins are in some ways intermediate between typical swallows and other passerine birds, and the arrangement of their leg muscles is more like that of a typical passerine than of a swallow. The extent of their differences from other swallows and the wide geographical separation of these two martins suggest that they are relict populations of
576-546: A distinctive appearance. The term "swallow" is used as the common name for Hirundo rustica in the UK and Ireland . Around 90 species of Hirundinidae are known, divided into 21 genera , with the greatest diversity found in Africa, which is also thought to be where they evolved as hole-nesters. They also occur on a number of oceanic islands. A number of European and North American species are long-distance migrants ; by contrast,
672-422: A few days to begin to sprout, and the chicks are brooded by the parents until they are able to thermoregulate . On the whole, they develop slowly compared to other passerine birds. The parents do not usually feed the chicks individual insects, but instead feed a bolus of food comprising 10–100 insects. Regardless of whether the species has males that incubate or brood the chicks, the males of all hirundines help feed
768-534: A flock of 15,000 birds was seen in Gabon in 1997. Investigations in Gabon in September 2003 extended the known range of this martin. More than 300 birds were found with hundreds of rosy bee-eaters in the Omboué area and the newly established Iguéla National Park, and a mixed flock with rosy bee-eaters at Loango National Park in Gabon was estimated at 100,000 birds in total. In January 2010, 250 martins were seen at
864-407: A group of species that diverged from the main swallow lineage early in its evolutionary history. Like other early hirundine lineages, these martins nest in self-excavated burrows, rather than adopted nest holes or mud nests. Their physical characteristics and breeding behaviour suggest that they may be the most primitive of the swallows. The genus name Pseudochelidon (Hartlaub, 1861) comes from
960-493: A light buoyant flight and feed on insects caught in the air. They appear to be more terrestrial than other swallows, frequently walking rather than perching, and the white-eyed may be crepuscular . The African species excavates nest holes in sandy ridges in rivers, while the breeding locations and habits of the Asian bird are unknown. When the African river martin was first discovered in the 19th century, Gustav Hartlaub thought it
1056-420: A mean body mass of 9.4 g (0.33 oz) while the purple martin and southern martin , which both weigh in excess of 50 g (1.8 oz) on average, rival one another as the heaviest swallows. The wings are long, pointed, and have nine primary feathers. The tail has 12 feathers and may be deeply forked, somewhat indented, or square-ended. A long tail increases maneuverability, and may also function as
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#17327832858871152-405: A moral lesson about greed and altruism through the mending of a swallow's broken leg. During the 19th century, Jean Desbouvrie attempted to tame swallows and train them for use as messenger birds, as an alternative to war pigeons . The swallows would have a light load of course, as a laden swallow could only travel about half as far as an unladen swallow in the same trip. He succeeded in curbing
1248-961: A new location in Bakoumba , and single birds were observed in hirundine flocks near Moanda , at Mounana , and at Lekoni . Despite sightings of large flocks and a population which may exceed 100,000, the species is classed by the IUCN as Data Deficient due to the lack of detailed information on its range and numbers. This species is protected under national laws in the DRC ( Loi portant réglémentation de la chasses , 1985), and Gabon ( Loi d'orientation en matière des eaux et forêts , 1982 and Loi relative à la protection et à l'amélioration de l'environnement , 1993), and by regional legislation in Nigeria, which does not have national wildlife laws. The Nigerian laws are based directly on older colonial era laws which include
1344-482: A number of species occasionally consume fruits and other plant matter. Species in Africa have been recorded eating the seeds of Acacia trees, and these are even fed to the young of the greater striped swallow . The swallows generally forage for prey on the wing, but they on occasion snap prey off branches or on the ground. The flight may be fast and involve a rapid succession of turns and banks when actively chasing fast-moving prey; less agile prey may be caught with
1440-456: A number of species, such as this martin, which are not native to the country. The African river martin is not a protected species in the Republic of Congo. In the 1950s, this martin was caught and eaten in large quantities in the DRC by the local population, and this practice could be increasing. The African river martins and the bee-eaters with which they share their colonies are dug out of
1536-585: A real evolutionary separation. In the New World, "martin" is reserved for members of the genus Progne . (These two systems are responsible for the same species being called sand martin in the Old World and bank swallow in the New World.) The family Hirundinidae was introduced (as Hirundia) by the French polymath Constantine Samuel Rafinesque in 1815. The Hirundinidae are morphologically unique within
1632-497: A separate genus Eurochelidon due to its significant differences from the African species, it remains a member of the same subfamily. Genetic studies confirmed that the two river martins form a distinct clade from the typical swallows in the Hirundininae subfamily. The river martins are in some ways intermediate between typical swallows and other passerines : they have stout bills, large feet and relatively strong legs, which
1728-498: A separate genus Eurochelidon , leaving the African river martin in a monotypic genus. This treatment was contested by other authorities, and most authors retain the two species in Pseudochelidon , BirdLife International being a notable exception. The adult African river martin is a large swallow, 14 cm (5.5 in) long. It is mainly black, with a silky blue-green gloss to the head, becoming distinctly green on
1824-407: A sexual adornment, since the tail is frequently longer in males. In barn swallows, the tail of the male is 18% longer than those of the female, and females select mates on the basis of tail length. Their legs are short, and their feet are adapted for perching rather than walking, as the front toes are partially joined at the base. Swallows are capable of walking and even running, but they do so with
1920-400: A shuffling, waddling gait. The leg muscles of the river martins ( Pseudochelidon ) are stronger and more robust than those of other swallows. The river martins have other characteristics that separate them from the other swallows. The structure of the syrinx is substantially different between the two subfamilies; and in most swallows, the bill, legs, and feet are dark brown or black, but in
2016-426: A single genus, Pseudochelidon , due to their having a number of structural similarities. However, Brooke proposed that the white-eyed river martin be placed in a separate monotypic genus Eurochelidon . The African river martin has a restricted distribution; it appears to be locally numerous, although its true status has not been fully investigated. The white-eyed river martin was discovered as recently as 1969 and
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#17327832858872112-408: A slower, more leisurely flight that includes flying in circles and bursts of flapping mixed with gliding. Where several species of swallows feed together, they separate into different niches based on height off the ground, some species feeding closer to the ground and others feeding at higher levels. Similar separation occurs where feeding overlaps with swifts . Niche separation may also occur with
2208-472: A softer, fleshier, and much less prominent gape (fleshy interior of the bill) than its Thai relative. The bill of the white-eyed river martin also averages 22.5% wider than that of the African river martin. Following a suggestion by the Thai bird's discoverer, Kitti Thonglongya , Richard Brooke proposed in 1972 that the white-eyed river martin was sufficiently different from the African species to be placed in
2304-410: A state of torpor , or even that they withdrew for the winter under water. Aristotle ascribed hibernation not only to swallows, but also to storks and kites . Hibernation of swallows was considered a possibility even by as acute an observer as Rev. Gilbert White , in his The Natural History and Antiquities of Selborne (1789, based on decades of observations). This idea may have been supported by
2400-434: A while after the breeding season. If a human being gets too close to their territory, swallows attack them within the perimeter of the nest. Colonial species may mob predators and humans that are too close to the colony. For the most part, swallows are insectivorous, taking flying insects on the wing. Across the whole family, a wide range of insects is taken from most insect groups, but the composition of any one prey type in
2496-404: A whitish rump, a white eye and eye-ring, and a yellow bill. The African has a red eye-ring and bill and lacks a contrasting rump patch or tail streamers. The juveniles of both species are similar to the adults, but with brown heads, and young white-eyeds lack the long tail streamers of the adults. The African river martin has a chee chee or cheer-cheer-cheer call when it is flying in flocks. It
2592-692: Is Miochelidon eschata from the Early Miocene of Siberia ; it is the only record of Hirundinidae from the Miocene . It is likely a basal member of the family. The Hirundinidae have an evolutionarily conservative body shape, which is similar across the clade , but is unlike that of other passerines . Swallows have adapted to hunting insects on the wing by developing a slender, streamlined body and long, pointed wings, which allow great maneuverability and endurance, as well as frequent periods of gliding. Their body shapes allow for very efficient flight ;
2688-399: Is actually migratory at all. The African species' breeding habitat consists of forested rivers with islands with sandy shores for breeding. The nesting grounds of the white-eyed river martin are unknown, but if the breeding habitat resembles that of its relative, it is likely to be the forested valleys of large rivers, which can provide sandbars and islands for nesting, and woodland over which
2784-496: Is mainly from December to March. Three or four birds were seen passing through the southern Central African Republic in 1994. This martin's breeding requirement is forested rivers with islands that have sandy banks for nest burrows, and its habitat in the DRC is tropical forest with over 200 cm (78.5 in) of rain a year. This area is a patchwork of dry, seasonally flooded and permanently wet woodland, and seasonally flooded savanna , all of which are subject to inundation by
2880-407: Is only known from specimens and anecdotal evidence – no modern ornithologists have seen the species in the wild, and its breeding grounds are unknown. It may be extinct , although a possible sighting was reported in 2004. When a specimen of the African river martin from Gabon was first formally described by German zoologist Gustav Hartlaub in 1861, it was not initially identified as a member of
2976-788: Is presumed to be the reason behind the decline of the critically endangered white-eyed river martin , a species that is only known from a few specimens collected in Thailand . The species presumably breeds in riverbanks, a much diminished habitat in Southeast Asia. As the species has not been reliably seen since 1980, it may already be extinct. Two insular species, the Bahama swallow and golden swallow , have declined due to forest loss and also competition with introduced species such as starlings and sparrows, which compete with these swallows for nesting sites. The golden swallow formerly bred on
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3072-406: Is unusual in aerial feeders. They also have a large syrinx (vocal organ) and a different bronchial structure. 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 evolutionary history, and they may be the most primitive of
3168-500: Is very vocal during migration, giving harsh gull-like calls, and appears to have a jingling courtship song. No calls have been described for the white-eyed river martin. The two members of the subfamily have geographically separate ranges. The African river martin breeds along the Congo and Ubangi rivers in the Democratic Republic of the Congo . It is migratory , wintering in coastal savannah in southern Gabon and
3264-533: The Ancient Greek language prefix ψευδο/pseudo , meaning "false", and χελιδον / chelidôn , meaning "swallow". The species name reflects the superficial similarity to the rollers of the genus Eurystomus . 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 able to take much larger prey. The African species has
3360-440: The Ancient Greek prefix ψευδο/pseudo , "false", and χελιδων / chelidôn , "swallow", reflecting its distinctiveness from the "true" swallows. For many years the African river martin was the sole member of its genus and subfamily until the discovery of the white-eyed river martin, Pseudochelidon eurystomina , by Thai ornithologist Kitti Thonglongya in 1968. Although some authorities follow Brooke in placing that species in
3456-1050: The Indian Ocean , and a number of migratory species are common vagrants to other isolated islands and even to some sub-Antarctic islands and Antarctica. Many species have enormous worldwide ranges, particularly the barn swallow, which breeds over most of the Northern Hemisphere and winters over most of the Southern Hemisphere. The family uses a wide range of habitats. They are dependent on flying insects, and as these are common over waterways and lakes, they frequently feed over these, but they can be found in any open habitat, including grasslands, open woodland, savanna, marshes, mangroves, and scrubland, from sea level to high alpine areas. Many species inhabit human-altered landscapes, including agricultural land and even urban areas. Land-use changes have also caused some species to expand their range, most impressively
3552-1209: The International Ornithological Committee (IOC). Pseudochelidon – river martins (2 species) Psalidoprocne – saw-wings (5 species) Ptyonoprogne – crag martins (5 species) Hirundo – swallows (16 species) Atronanus – forest swallow Delichon – house martins (4 species) Petrochelidon – includes cliff swallows (10 species) Cecropis – swallows (9 species) Pseudhirundo – grey-rumped swallow Cheramoeca – white-backed swallow Phedina – Mascarene martin Neophedina – banded martin Phedinopsis – Brazza's martin Riparia – martins (6 species) Tachycineta – swallows (9 species) Progne – martins (9 species) Stelgidopteryx – rough-winged swallows (2 species) Atticora – swallows (3 species) Pygochelidon – swallows (2 species) Alopochelidon – tawny-headed swallow Orochelidon – swallows (3 species) The oldest known fossil swallow
3648-653: The Republic of Congo ; it has recently been discovered to nest in beach ridges and grassland in its coastal wintering areas. The white-eyed river martin is known only from its wintering site at Bueng Boraphet lake in Thailand, where it was seen between the months of November and February. It may be migratory, but its breeding grounds and habitat are unknown, although river valleys in Northern Thailand or south-western China are possibilities, as are Cambodia and Myanmar . However, doubts have been cast on whether it
3744-406: The Republic of the Congo . The DRC breeding population is migratory , wintering in coastal savanna in Gabon, but it is not known if the birds nesting at the coast are a separate population, or if the migrants are breeding again in the wintering area. Westwards migration from the DRC is from June to early September, with birds arriving at the coast from mid-August to mid-September. Return migration
3840-409: The swallow family , Hirundinidae. When discovered, it was not initially recognised as a swallow, and its structural differences from most of its relatives, including its stout bill and robust legs and feet, have led to its current placement in a separate subfamily shared only with the Asian white-eyed river martin . The African river martin is a large swallow, mainly black with a blue-green gloss to
3936-466: The welcome swallow , which began to colonise New Zealand in the 1920s, started breeding in the 1950s, and is now a common landbird there. Species breeding in temperate regions migrate during the winter when their insect prey populations collapse. Species breeding in more tropical areas are often more sedentary, although several tropical species are partial migrants or make shorter migrations. In antiquity , swallows were thought to have hibernated in
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4032-560: The Bueng 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. Past surveys include several at Bueng Boraphet, a 1969 survey of the Nan Yom and Wang Rivers of northern Thailand, and
4128-707: The Congo . Breeding also occurs in these coastal areas, but it is unknown whether the migrants are raising a second brood or if there is a separate resident population. This martin feeds in flocks throughout the year, catching a variety of insects in the air, especially flying ants . It does not use perches during the breeding season, although it will often land on the ground. The African river martin nests in burrows in river sand banks, often alongside rosy bee-eaters , but its incubation and fledging times are not known. It also digs tunnels for night-time shelter when in its wintering areas. It appears to be common within its restricted range, despite being caught in large numbers by
4224-635: The Congo River and its tributaries. The swamp forests contain trees such as Symphonia globulifera , raffia palms and Mitragyna species, and the riverbanks are often lined with arrowroot . This specialised habitat is shared with two other restricted-range birds, the Congo sunbird and the Congo martin . The main coastal breeding area in Gabon, around Gamba , has a similar mosaic of habitats, with mangroves , swamp forests, wet evergreen woodlands and seasonally wet savanna. There are also two large lagoons, and drier areas of grassland and forest. All
4320-462: The DRC by the local population, and this practice could be increasing. Breeding colonies in river sandbars are also liable to flooding, but thousands of birds were breeding on the grasslands east of Gamba as recently as 2005. African river martin The African river martin ( Pseudochelidon eurystomina ) is a passerine bird , one of two members of the river martin subfamily of
4416-590: The IUCN will not categorise it as such until extensive targeted surveys have been conducted. Despite legal protection under Appendix 1 of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreement, it was captured by locals along with other swallows for sale as food or for release by devout Buddhists. Following its discovery by ornithologists, trappers were reported to have caught as many as 120 and sold them to
4512-447: The Old World members) and cavity adoption (in New World members) as strategies, and the genus Hirundo and its allies use mud nests. The genus level cladogram shown below is based on a molecular phylogenetic study by Drew Schield and collaborators that was published in 2024. The choice of genera and the number of species is taken from the list of birds maintained by Frank Gill , Pamela C. Rasmussen and David Donsker on behalf of
4608-435: The Old World, particularly Africa, whereas cavity-nesters are more common in the New World. Mud-nesting species in particular are limited in areas of high humidity, which causes the mud nests to crumble. Many cave-, bank-, and cliff-dwelling species of swallows nest in large colonies. Mud nests are constructed by both males and females, and amongst the tunnel diggers, the excavation duties are shared, as well. In historical times,
4704-536: The Pseudochelidoninae, which are composed of the two species of river martins, and the Hirundininae, into which the remaining species are placed. The division of the Hirundininae has been the source of much discussion, with various taxonomists variously splitting them into as many as 24 genera and lumping them into just 12. Some agreement exists that three core groups occur within the Hirundininae:
4800-472: The West and South African swallows are nonmigratory. This family comprises two subfamilies: Pseudochelidoninae (the river martins of the genus Pseudochelidon ) and Hirundininae (all other swallows, martins, and saw-wings). In the Old World, the name "martin" tends to be used for the squarer-tailed species, and the name "swallow" for the more fork-tailed species; however, this distinction does not represent
4896-626: The adult male probably being the most common distinction. The chicks hatch naked and with closed eyes. Fledged juveniles usually appear as duller versions of the adult. The family has a worldwide cosmopolitan distribution , breeding on every continent except Antarctica. One species, the Pacific swallow , occurs as a breeding bird on a number of oceanic islands in the Pacific Ocean, the Mascarene martin breeds on Reunion and Mauritius in
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#17327832858874992-626: The air, and this martin is very vocal during migration, giving harsh gull-like calls. The African river martin breeds along the Congo River and its tributary, the Ubangi in the Democratic Republic of the Congo (DRC), an area estimated at 47,000 km (18,150 mi ). This part of Africa is poorly known, and this martin may also breed on other tributaries, such as the Kasai , or on other suitable rivers. It also breeds in southern Gabon and
5088-437: The back and wing coverts . The underparts, other than the brownish under-wings, are purple-black, and the flight feathers are black. The black square tail is 4.8 cm (1.9 in) long, and the soft feather shafts project beyond the barbed section. This feature is most pronounced in the two central feathers, which in the related white-eyed river martin are greatly elongated. The African river martin has brown legs with
5184-468: The birds breeding in the DRC and those breeding in coastal areas of Gabon and the Republic of Congo. A flock of 15,000 birds was seen in 1997, and a mixed flock with rosy bee-eater Merops malimbicus was estimated at 100,000 birds; nevertheless, due to the lack of detailed information, the species is classed by the IUCN as Data Deficient . In the 1950s, the species was caught and eaten in large quantities in
5280-432: The birds can catch insect prey. The African river martin uses coastal savannah as its winter habitat. Based on its only known wintering site, the non-breeding habitat of the white-eyed is assumed to be in the vicinity of open fresh water for feeding, with reed-beds for the night-time roost. Breeding behaviour is known only for the African river martin. It nests in large colonies of up to 800 birds from December to April, when
5376-400: The body condition of the bird and are presumably used by females to judge the physical condition and suitability for mating of males. Begging calls are used by the young when soliciting food from their parents. The typical song of swallows is a simple, sometimes musical twittering. Species of hirundine that are threatened with extinction are generally endangered due to habitat loss . This
5472-449: The breeding areas form part of a belt of forest that stretches from southern Cameroon through Gabon to the northern parts of the Republic of Congo, and extends through most of the DRC up to its eastern mountains. Outside of the breeding season, this martin roosts in reed-beds or riverine vegetation. The African river martin has flight displays in which pairs or small groups chase each other while making jingling calls. It also displays on
5568-511: The breeding burrows for food. Breeding colonies in river sandbars are liable to flooding, but thousands of birds were breeding on the grasslands east of Gamba as recently as 2005. Swallow 21, see text The swallows , martins , and saw-wings , or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica . Highly adapted to aerial feeding, they have
5664-586: The breeding season. Although it has been assumed that the breeding habits of the white-eyed species resemble those of the African species, distinctive differences in foot and toe morphology suggest that it might not use a burrow for nesting. The African river martin feeds in flocks over river and forest, often far from water. It eats insects , mainly taking winged ants . The flight is strong and fast, interspersed with glides. Wintering birds regularly perch on treetops, wires and roofs. The white-eyed river martin feeds on insects , including beetles , which are caught on
5760-433: The chicks. When the young fledge is difficult to determine, as they are enticed out of the nest after three weeks by parents, but frequently return to the nest afterwards to roost. Swallows are able to produce many different calls or songs, which are used to express excitement, to communicate with others of the same species, during courtship, or as an alarm when a predator is in the area. The songs of males are related to
5856-417: The contribution of male swallows towards parental care is the highest of any passerine bird. The eggs of swallows tend to be white, although those of some mud-nesters are speckled. The typical clutch size is around four to five eggs in temperate areas and two to three eggs in the tropics. The incubation duties are shared in some species, and in others the eggs are incubated solely by the females. Amongst
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#17327832858875952-469: The diet varies by species and with the time of year. Individual species may be selective; they do not scoop up every insect around them, but instead select larger prey items than would be expected by random sampling. In addition, the ease of capture of different insect types affects their rate of predation by swallows. They also avoid certain prey types; in particular, stinging insects such as bees and wasps are generally avoided. In addition to insect prey,
6048-509: The director of the Nakhon Sawan Fisheries Station who was unable to keep them alive in captivity. The small population may therefore have become non-viable. One factor that reduces the chances of re-discovering the white-eyed martin is the drastic decline in the numbers of swallows wintering at Bueng Boraphet , its only known site, from the hundreds of thousands reported around 1970 to maximum counts of 8,000 made in
6144-473: The female is away to reduce heat loss (this is different from incubation as that involves warming the eggs, not just stopping heat loss). Incubation stints last for 5–15 minutes and are followed by bursts of feeding activity. From laying, swallow eggs take 10–21 days to hatch, with 14–18 days being more typical. The chicks of swallows hatch naked, generally with only a few tufts of down. The eyes are closed and do not fully open for up to 10 days. The feathers take
6240-429: The ground, and once it has landed, it may walk around or cleanse itself with the sand. It feeds in flocks often far from the colony. Wintering birds use elevated perches much more readily, landing on treetops, wires and roofs, and feed in flight over rivers and forests, often far from water. The flocks feed on insects including flies , small beetles and bugs , but mainly on winged ants . Wintering birds dig tunnels in
6336-423: The ground, with the wings drooped and slightly open, and the head raised but held horizontally; the function of these terrestrial displays is uncertain. This species nests in colonies in sandbanks along forested rivers from December to April when the river is low. The colonies, sometimes shared with rosy bee-eaters in Gabon, may contain up to 800 birds, each pair excavating a 1–2 m (39–79 in) long tunnel in
6432-458: The habit of some species to roost in some numbers in dovecotes, nests and other forms of shelter during harsh weather, and some species even entering torpor. There were several reports of suspected torpor in swallows from 1947, such as a 1970 report that white-backed swallows in Australia may conserve energy this way, but the first confirmed study that they or any passerine entered torpor was
6528-410: The head and a greener tint to the back and wings. The under-wings are brownish, the underparts are purple-black, and the flight feathers are black. This martin has red eyes, a broad orange-red bill and a black, square tail. Young birds are similar in appearance to the adults, but have browner plumage . This species has a variety of unmusical calls, and displays both in flight and on the ground, although
6624-455: The head. The morphology of the eye in swallows is similar to that of a raptor. Like the unrelated swifts and nightjars , which hunt in a similar way, they have short bills, but strong jaws and a wide gape. Their body lengths range from about 10–24 cm (3.9–9.4 in) and their weight from about 10–60 g (0.35–2.12 oz). The smallest species by weight may be the Fanti sawwing , at
6720-652: The introduction of man-made stone structures such as barns and bridges, together with forest clearance, has led to an abundance of colony sites around the globe, significantly increasing the breeding ranges of some species. Birds living in large colonies typically have to contend with both ectoparasites and conspecific nest parasitism . In barn swallows, old mated males and young unmated males benefit from colonial behaviour, whereas females and mated young males likely benefit more from nesting by themselves. Pairs of mated swallows are monogamous, and pairs of nonmigratory species often stay near their breeding area all year, though
6816-516: The island of Jamaica , but was last seen there in 1989 and is now restricted to the island of Hispaniola . Swallows are tolerated by humans because of their beneficial role as insect eaters, and some species have readily adapted to nesting in and around human habitation. The barn swallow and house martin now rarely use natural sites. The purple martin is also actively encouraged by people to nest around humans and elaborate nest boxes are erected. Enough artificial nesting sites have been created that
6912-480: The local population for food, and large flocks are sometimes seen. However, due to a lack of detailed information about its breeding range and population numbers, this species is classed as Data Deficient by the International Union for Conservation of Nature (IUCN). When German zoologist Gustav Hartlaub first described the African river martin in 1861, it was not initially thought to be a member of
7008-405: The metabolic rate of swallows in flight is 49–72% lower than equivalent passerines of the same size. Swallows have two foveae in each eye, giving them sharp lateral and frontal vision to help track prey. They also have relatively long eyes, with their length almost equaling their width. The long eyes allow for an increase in visual acuity without competing with the brain for space inside of
7104-441: The nest site is defended most vigorously during the breeding season. Migratory species often return to the same breeding area each year, and may select the same nest site if they were previously successful in that location. First-year breeders generally select a nesting site close to where they were raised. The breeding of temperate species is seasonal, whereas that of subtropical or tropical species can either be continuous throughout
7200-471: The passerines, with molecular evidence placing them as a distinctive lineage within the Sylvioidea ( Old World warblers and relatives). Phylogenetic analysis has shown that the family Hirundinidae is sister to the cupwings in the family Pnoepygidae . The two families diverged in the early Miocene around 22 million years ago. Within the family, a clear division exists between the two subfamilies,
7296-559: The purple martin now seldom nests in natural cavities in the eastern part of its range. Because of the long human experience with these conspicuous species, many myths and legends have arisen as a consequence, particularly relating to the barn swallow. Roman historian Pliny the Elder described a use of painted swallows to deliver a report of the winning horses at a race. There is also the Korean folktale of Heungbu and Nolbu , which teaches
7392-411: The purpose of the terrestrial display is unknown. The main breeding areas are in the Democratic Republic of the Congo (DRC) along the Congo River and its tributary, the Ubangi , in habitats characterised by a mixture of tropical forest types including swampy or seasonally flooded woodland. The African river martin is migratory , wintering in coastal savanna in southern Gabon and the Republic of
7488-405: The river levels are low. Each pair excavates a 1–2 m (39–79 in) long tunnel in the exposed sandbanks. The pocket at the end of the tunnel has a few twigs and leaves to serve as a nest, onto which two to four unspotted white eggs are laid. It has chasing flight displays and will walk on the ground; it also displays on the ground, but the function of this is uncertain. It rarely perches during
7584-415: The river martins, the bill is orange-red and the legs and feet are pink. The most common hirundine plumage is glossy dark blue or green above and plain or streaked underparts, often white or rufous. Species that burrow or live in dry or mountainous areas are often matte brown above (e.g. sand martin and crag martin ). The sexes show limited or no sexual dimorphism , with longer outer tail feathers in
7680-533: The sand in which to roost overnight. The total population size of the African river martin is unknown. In the late 1980s, it appeared to be common, if local, and large numbers were seen on migration in Gabon. However, it is particularly poorly studied in the Democratic Republic of the Congo (DRC), and it is not known if there is any relationship between the birds breeding in the DRC and those breeding in coastal areas of Gabon and Congo. Several hundred birds were seen at Conkouati-Douli National Park in Congo in 1996 and
7776-442: The sandbar. Two to four unspotted white eggs are laid onto a few twigs and leaves in the pocket at the end of the tunnel. The eggs measure 21.9 mm–26.0 mm × 16.4 mm–18.2 mm (0.86 in–1.02 in × 0.65 in–0.72 in). The incubation and fledging times are unknown, although it is believed that both parents care for the nestlings. In the breeding areas, this martin rarely uses perches other than
7872-400: The saw-wings of the genus Psalidoprocne , the core martins, and the swallows of the genus Hirundo and their allies. The saw-wings are the most basal of the three, with the other two clades being sister to each other. The phylogeny of the swallows is closely related to evolution of nest construction; the more basal saw-wings use burrows as nest, the core martins have both burrowing (in
7968-555: The season or local circumstances. The white-eyed river martin was seen in Thailand in 1972, 1977 and 1980, but not definitely since. There are unconfirmed sightings from Thailand in 1986 and Cambodia in 2004. It is classified as critically endangered by the International Union for the Conservation of Nature and Natural Resources (IUCN). This designation means that a species' numbers have decreased, or will decrease, by 80% within three generations. This species may be extinct, but
8064-539: The sexes are small even to the birds' perception. Juveniles are duller and have sooty brown heads. The moult to adult plumage takes place in the wintering areas and is largely complete by October. The African river martin has a strong, fast flight interspersed with glides. It is a vocal species with a variety of sounds. It has a jingling song given in the aerial breeding display, and a number of contact calls, kee-r-r , chee-chee and similar short, unmusical sounds. Flocks call together, cheer-cheer-cheer , as they take to
8160-450: The size of prey chosen. The more primitive species nest in existing cavities, for example in an old woodpecker nest, while other species excavate burrows in soft substrate such as sand banks. Swallows in the genera Hirundo , Ptyonoprogne , Cecropis , Petrochelidon , Atronanus and Delichon build mud nests close to overhead shelter in locations that are protected from both the weather and predators. The mud-nesters are most common in
8256-525: The species might be nocturnal or crepuscular , a factor that could make it highly cryptic and thus partly explain how such a distinctive species remained undetected for so long. Although the fact that the first specimens were supposedly collected roosting at night in reed-beds might be a contraindication, it is possible that the birds might not actually have been caught at the roost; or they might be crepuscular, feeding at dawn and dusk; or they might be capable of both diurnal and nocturnal behaviour, depending on
8352-545: The species of swallow; in colonial-nesting species, it tends to be small, but it may be much larger for solitary nesters. Outside the breeding season, some species may form large flocks, and species may also roost communally. This is thought to provide protection from predators, such as sparrowhawks and hobbies . These roosts can be enormous; one winter-roosting site of barn swallows in Nigeria attracted 1.5 million individuals. Nonsocial species do not form flocks, but recently fledged chicks may remain with their parents for
8448-539: The species where the males help with incubation, their contribution varies amongst species, with some species such as the cliff swallow sharing the duties equally and the female doing most of the work in others. Amongst the barn swallows, the male of the American subspecies helps (to a small extent), whereas the European subspecies does not. Even in species where the male does not incubate the eggs, he may sit on them when
8544-416: The subfamily is the white-eyed river martin Pseudochelidon sirintarae , known only from one site in Thailand and possibly extinct. These two species possess a number of features which distinguish them from other swallows and martins, including their robust legs and feet, stout bills, large syrinxes (vocal organs) and different bronchial structure. Genetic studies confirmed that the two river martins form
8640-404: The swallow and martin family, and he placed it with the rollers . Later authors either placed it in its own monotypic family, or with the woodswallows . A 1938 study of this martin's anatomy by Percy Lowe revealed that the species was closest to the swallows and martins, but sufficiently distinct from them to be placed in a separate subfamily, Pseudochelidoninae. The only other member of
8736-437: The swallow and martin family. Hartlaub placed it with the rollers , and later authors either put it in its own separate family, or with the woodswallows . It was only following study of the anatomy of the species by Lowe that it was determined to be closely related to the swallows and martins, but sufficiently different that it could be placed in a separate subfamily Pseudochelidoninae. The genus name Pseudochelidon comes from
8832-487: The swallows. Like other early hirundine lineages, they nest in burrows, rather than adopted nest holes or mud nests. Both species are medium-sized (14–18 cm or 5.5–7.1 in), mainly black-plumaged swallows, unlikely to be confused with any other hirundine in their respective ranges. Adults of both species have large, blue-glossed heads, a green tinge to the body plumage, and brown wings. The sexes are similar in plumage. The white-eyed has elongated outer tail feathers,
8928-540: The wing. Given its size and unusual mouth structure, it may 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. This behaviour, together with its unusual toe-shape and the fact that mud was found on the toes of one of the first specimens, suggests that this species may be relatively terrestrial. In winter, it roosts with barn swallows in reedbeds . Pamela C. Rasmussen suggested that, given its unusually large eyes,
9024-419: The winter of 1980–1981. It is not certain whether 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
9120-456: The year or seasonal. Seasonal species in the subtropics or tropics usually time their breeding to coincide with the peaks in insect activity, which is usually the wet season, but some species, such as the white-bibbed swallow , nest in the dry season to avoid flooding in their riverbank nesting habitat. All swallows defend their nests from egg predators, although solitary species are more aggressive towards predators than colonial species. Overall,
9216-421: Was a roller , and later authors either placed it in its own family, or with the woodswallows . Study of the anatomy revealed that the species was closest to the swallows and martins, but that it possessed a number of distinctive features, such as its robust legs and feet and stout bill. These indicated that it should be placed in a separate subfamily. The two river martin species are usually considered to belong to
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