African River Martin
Encyclopedia
The African River Martin (Pseudochelidon eurystomina) 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. Its structural differences from most other swallows, including its robust legs and feet and stout bill
, indicate that it should be placed with the Asian White-eyed River Martin
in a separate subfamily.
It breeds along the Congo River
and its tributary, the Ubangi
. It nests in burrows in sand banks, and appears to be common common within its restricted range, despite being caught in large numbers by the local population for food. It is migratory
, wintering in coastal savannah in southern Gabon
and the Republic of Congo. Many birds remain to breed in the wintering zones. This martin feeds on insects caught in the air and frequently walks on the ground rather than perching in trees. Due to a lack of detailed information about its population numbers, this species is classed as Data Deficient by the International Union for Conservation of Nature.
, who first described it in 1861, placed it with the roller
s, and later authors either placed it in its own family, or with the woodswallow
s. Study of the anatomy of the species by Lowe
(1938) revealed that the species was closest to the swallows and martins, but sufficiently distinct to be placed in a separate subfamily Pseudochelidoninae.
The genus name Pseudochelidon (Hartlaub
, 1861) comes from 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 only other member of 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 distinctive features which distinguish them from other swallows and martins, including their robust legs and feet, stout bill, large syrinx
(vocal organ) and a different bronchial
structure. Genetic studies confirmed that the two river martins form a distinct clade
from the typical swallows in the Hirundininae subfamily.
The two river martins are in some ways intermediate between typical swallows and other passerine
s. 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
ary history, and that they may be the most primitive of the swallows. Like other early hirundine lineages, they nest in burrows, rather than adopted nest holes or mud nests.
The African River Martin breeds along the Congo River
and its tributary, the Ubangi
in the Democratic Republic of the Congo
, an area estimated at 47,000 km2 (18,150 mi2). Its breeding habitat consists of forested rivers with islands that have sandy banks for burrowing. It is migratory
, wintering in coastal savannah in southern Gabon
and the Republic of the Congo
; many birds stay to breed in the wintering areas. Outside the breeding season it roosts in reed-beds or riverine vegetation.
. The underparts, other than the brownish under-wings, are purple-black, and the flight feather
s are black. The tail is square and the midrib of the feathers extends slightly beyond the end of the webbing. This species has red eyes, pink eye-rings, and a broad orange red bill. The legs are brown.
The sexes are similar, but 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. This species gives a short chee chee or similar call, and flocks call together, cheer-cheer-cheer. This martin is very vocal during migration, giving harsh gull-like
calls. The flight is strong and fast, interspersed with glides.
s in Gabon) of up to 800 birds, each pair excavating a 1–2 m (39–78 in) long tunnel in the sandbars. 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. The eggs measure 21.9–26.0 x 16.4–18.2 mm (0.86–1.0 x 0.65–0.72 in). The incubation and fledging times are unknown, although it is believed that both parents care for the nestlings.
It rarely perches on the breeding grounds and will walk on the ground; however, wintering birds regularly perch on treetops, wires and roofs. It has chasing flight displays, and it also displays on the ground, though the function of these displays is uncertain. The African River Martin feeds in flocks over rivers and forests, often far from water, on insect
s, mainly taking winged ant
s.
Merops malimbicus was estimated at 100,000 birds. Several hundred birds were also seen at Conkouati-Douli National Park
in 1996. 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 the DRC by the local population, and this practice could be increasing. Breeding colonies in river sandbars are liable to flooding, but thousands of birds were breeding on the grassland
s east of Gamba as recently as 2005.
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 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 a medium-sized, mainly black-plumaged species with red eyes, a broad orange-red bill and a square tail. Its structural differences from most other swallows, including its robust legs and feet and stout bill
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...
, indicate that it should be placed with the Asian White-eyed River Martin
White-eyed River Martin
The White-eyed River Martin is a passerine bird, one of only two members of the river martin subfamily of the swallow family Hirundinidae...
in a separate subfamily.
It breeds along the Congo River
Congo River
The Congo River is a river in Africa, and is the deepest river in the world, with measured depths in excess of . It is the second largest river in the world by volume of water discharged, though it has only one-fifth the volume of the world's largest river, the Amazon...
and its tributary, the Ubangi
Ubangi River
The Ubangi River , also spelled Oubangui, is the largest right-bank tributary of the Congo River of Central Africa. It begins at the confluence of the Mbomou and Uele Rivers and flows west, then bends to the southwest and passes through Bangui, after which it flows south to the Congo at Liranga....
. It nests in burrows in sand banks, and appears to be common common within its restricted range, despite being caught in large numbers by the local population for food. It is 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...
, wintering in coastal savannah in southern Gabon
Gabon
Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west...
and the Republic of Congo. Many birds remain to breed in the wintering zones. This martin feeds on insects caught in the air and frequently walks on the ground rather than perching in trees. Due to a lack of detailed information about its population numbers, this species is classed as Data Deficient by the International Union for Conservation of Nature.
Taxonomy
When the African River Martin was first discovered in the 19th century, it was not thought to be a member of the swallow and martin family. German zoologist Gustav HartlaubGustav 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...
, who first described it in 1861, placed it with the roller
Roller
The rollers are an Old World family, Coraciidae, of near passerine birds. The group gets its name from the aerial acrobatics some of these birds perform during courtship or territorial flights. Rollers resemble crows in size and build, and share the colourful appearance of kingfishers and...
s, and later authors either placed it in its own family, or with the woodswallow
Woodswallow
Woodswallows are soft-plumaged, somber-coloured passerine birds. There is a single genus, Artamus, The woodswallows are either treated as a subfamily, Artaminae in an expanded family Artamidae, which includes the butcherbirds and Australian Magpie, or as the only genus in that family...
s. Study of the anatomy of the species by Lowe
Percy Lowe
Percy Roycroft Lowe was an English surgeon and ornithologist.Lowe was born at Stamford, Lincolnshire and studied medicine at Jesus College, Cambridge. He served as a civil surgeon in the Second Boer War, and it was whilst in South Africa that he became interested in ornithology...
(1938) revealed that the species was closest to the swallows and martins, but sufficiently distinct to be placed in a separate subfamily Pseudochelidoninae.
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
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean 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
Eurystomus
Eurystomus is a genus of the roller, one of the two genera in that family of birds. It contains four broad-billed species, which breed in Africa, Asia and Australasia. Two species are restricted to Africa, one of which, the Cinnamon Roller, is migratory. The Dollarbird has a large distribution...
.
The only other member of the subfamily is the White-eyed River Martin
White-eyed River Martin
The White-eyed River Martin is a passerine bird, one of only two members of the river martin subfamily of the swallow family Hirundinidae...
Pseudochelidon sirintarae, known only from one site in Thailand and possibly extinct. These two species possess a number of distinctive features which distinguish them from other swallows and martins, including their robust legs and feet, stout bill, large syrinx
Syrinx (biology)
Syrinx is the name for the vocal organ of birds. Located at the base of a bird's trachea, it produces sounds without the vocal cords of mammals. The sound is produced by vibrations of some or all of the membrana tympaniformis and the pessulus caused by air flowing through the syrinx...
(vocal organ) and a different bronchial
Bronchus
A bronchus is a passage of airway in the respiratory tract that conducts air into the lungs. The bronchus branches into smaller tubes, which in turn become bronchioles....
structure. Genetic studies confirmed that the two river martins form a distinct clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
from the typical swallows in the Hirundininae subfamily.
The two river martins are in some ways intermediate between typical swallows and other passerine
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...
s. 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...
ary history, and that they may be the most primitive of the swallows. Like other early hirundine lineages, they nest in burrows, rather than adopted nest holes or mud nests.
Distribution and habitat
Congo River
The Congo River is a river in Africa, and is the deepest river in the world, with measured depths in excess of . It is the second largest river in the world by volume of water discharged, though it has only one-fifth the volume of the world's largest river, the Amazon...
and its tributary, the Ubangi
Ubangi River
The Ubangi River , also spelled Oubangui, is the largest right-bank tributary of the Congo River of Central Africa. It begins at the confluence of the Mbomou and Uele Rivers and flows west, then bends to the southwest and passes through Bangui, after which it flows south to the Congo at Liranga....
in the Democratic Republic of the Congo
Democratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...
, an area estimated at 47,000 km2 (18,150 mi2). Its breeding habitat consists of forested rivers with islands that have sandy banks for burrowing. It is 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...
, wintering in coastal savannah in southern Gabon
Gabon
Gabon , officially the Gabonese Republic is a state in west central Africa sharing borders with Equatorial Guinea to the northwest, Cameroon to the north, and with the Republic of the Congo curving around the east and south. The Gulf of Guinea, an arm of the Atlantic Ocean is to the west...
and the Republic of the Congo
Republic of the Congo
The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by...
; many birds stay to breed in the wintering areas. Outside the breeding season it roosts in reed-beds or riverine vegetation.
Description
The adult African River Martin is large, at 14 cm (5.6 in) long. It is mainly black with a silky blue-green gloss to the head, becoming distinctly green on the back and wing covertsCovert (feather)
A covert feather on a bird is one of a set of feathers, called coverts, which as the name implies, cover other feathers. The coverts help to smooth airflow over the wings and tail.- Wing-coverts :...
. The underparts, other than the brownish under-wings, are purple-black, and the flight feather
Flight feather
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
s are black. The tail is square and the midrib of the feathers extends slightly beyond the end of the webbing. This species has red eyes, pink eye-rings, and a broad orange red bill. The legs are brown.
The sexes are similar, but juveniles are duller and have sooty brown heads. The 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...
to adult plumage takes place in the wintering areas and is largely complete by October. This species gives a short chee chee or similar call, and flocks call together, cheer-cheer-cheer. This martin is very vocal during migration, giving harsh gull-like
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...
calls. The flight is strong and fast, interspersed with glides.
Behaviour
The habitat requirement of this species consists of forested rivers with sandbanks for breeding. The breeding season is from December to April when the river is low. This species breeds in large colonies (sometimes with Rosy Bee-eaterRosy Bee-eater
The Rosy Bee-eater is a species of bird in the Meropidae family.It is found in Angola, Benin, Burkina Faso, Republic of the Congo, Democratic Republic of the Congo, Ivory Coast, Equatorial Guinea, Gabon, Ghana, Nigeria, and Togo....
s in Gabon) of up to 800 birds, each pair excavating a 1–2 m (39–78 in) long tunnel in the sandbars. 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. The eggs measure 21.9–26.0 x 16.4–18.2 mm (0.86–1.0 x 0.65–0.72 in). The incubation and fledging times are unknown, although it is believed that both parents care for the nestlings.
It rarely perches on the breeding grounds and will walk on the ground; however, wintering birds regularly perch on treetops, wires and roofs. It has chasing flight displays, and it also displays on the ground, though the function of these displays is uncertain. The African River Martin feeds in flocks over rivers and forests, often far from water, 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, mainly taking winged ant
Ant
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...
s.
Status
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 not known if there is any relationship between the birds breeding in the DRC and those breeding in coastal areas of Gabon and Congo. A flock of 15,000 birds was seen in 1997, and a mixed flock with Rosy Bee-eaterRosy Bee-eater
The Rosy Bee-eater is a species of bird in the Meropidae family.It is found in Angola, Benin, Burkina Faso, Republic of the Congo, Democratic Republic of the Congo, Ivory Coast, Equatorial Guinea, Gabon, Ghana, Nigeria, and Togo....
Merops malimbicus was estimated at 100,000 birds. Several hundred birds were also seen at Conkouati-Douli National Park
Conkouati-Douli National Park
The Conkouati-Douli National Park is a UNESCO recognised coastal national park in the Republic of the Congo. Created by Presidential Decree No. 99-136 on 14 August 1999, it covers an area of 504,950 ha and is located in the Kouilou Department, straddling the districts of Nzambi-Madingo and Kayes in...
in 1996. 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 the DRC by the local population, and this practice could be increasing. Breeding colonies in river sandbars are liable to flooding, but thousands of birds were breeding on the grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s east of Gamba as recently as 2005.
External links
- African River Martin videos on the Internet Bird collection