Long-tailed Ground-roller
Encyclopedia
The Long-tailed Ground Roller (Uratelornis chimaera) is a species
of bird
in the family
Brachypteraciidae, and is placed in the monotypic
genus
Uratelornis. This bird is endemic to arid spiny forest
s near the coast in southwestern Madagascar
. It occurs in extremely low population densities throughout its habitat. It requires shade and a deep layer of leaves in its habitat, and it is absent from parts of the spiny forest lacking these traits. It has no recognized subspecies, and its closest relative is believed to be the Scaly Ground Roller. The Long-tailed Ground Roller is the only ground roller to definitively display sexual dimorphism
, or differences in plumage or size between sexes. It is a medium-sized bird with a plump silhouette and a long tail. The upperparts are dark brown with black streaks while the underparts are light gray. The white throat is framed by black malar stripes and a black breastband, while a white stripe is present at the base of the bill. Sky blue feathers are visible at the edge of the wings and the tail. Calls are rarely made outside of the breeding season, though multiple territorial calls are made.
These ground rollers feed primarily on invertebrates, ranging from worms to butterflies. The bird searches through deep leaf litter for its prey or waits attentively for an opportunity. Its wings are relatively weak, so the ground roller primarily uses its strong legs to run through its habitat. The Long-tailed Ground Roller is a monogamous species, and defends a territory during the breeding season of October to February. The species digs a tunnel in the sand, at the end of which is a wider chamber where it makes its nest out of leaves and earthy pellets. Two to four eggs are laid. After the chicks fledge, the birds continue living in family groups for an unknown period of time after the breeding season before dispersing across the habitat.
This species is classified as Vulnerable
, and is threatened by habitat destruction. The arid spiny forests in which it lives are unprotected by the Madagascan government, and as such the species is losing habitat to slash-and-burn agriculture, charcoal collection, and logging. The species is also hunted by the native peoples of Madagascar.
in 1895. Rothschild described the species as Uratelornis chimaera, and published his description in the periodical of his private museum, Novitates Zoologicae. The Long-tailed Ground Roller is currently placed in the ground roller family. However, until recently the ground rollers, Cuckoo Roller, and roller
s were all placed in a single family in which each of the three groups formed a subfamily. In 1971 Joel Cracraft proposed erecting a separate family for the ground rollers based on dramatic differences in behavior, plumage, and post-cranial anatomy between the groups. This position is supported by DNA evidence, which also removed the Cuckoo Roller from the group. It has been suggested but not widely accepted that the ground rollers are closely related to the puffbird
s and jacamar
s. It is believed that the ancestor of the Long-tailed Ground Roller was an arboreal roller that invaded Madagascar from Africa and developed a terrestrial lifestyle before moving from the rainforests into the Long-tailed Ground Roller's arid scrubland. The adaptations required for the ancestral Long-tailed Ground Roller to inhabit scrubland led Rothschild to create the monotypic genus Uratelornis for the species in his description. No fossils have been found for this genus. Recent genetic analysis suggests that this species' closest relative is the Scaly Ground Roller. This species has no subspecies.
. It is highly distinctive from a distance due to its long tail and plump silhouette. The bird is 34 to 47 cm (13.4 to 18.5 in) long, although its tail can contribute up to 30 centimetres (11.8 in) of the length. This tail is the longest of the ground rollers. This ground roller has short wings and long, pinkish-brown legs. The male has a sandy buff crown and dark brown upperparts with black streaks. Its supercilium
is a pale buff color, while the ear-coverts are brown. The eyes are brown and the short and stout beak
is black. Its tongue is long with a brush-like tip to help it collect insects. A white stripe is present from the base of the bill and is surrounded by brown and black malar stripes. These malar stripes and the black breastband frame a white throat. The tail has 15 to 20 dark brown bars marking it, while the outer retrices are sky blue. This sky blue is also present on the wing-coverts. In flight, its two black and white bands on the primaries and secondaries are conspicuous. The underparts are a light gray, and the breast white. The toes are zygodactylous, with the first and fourth toes turned outwards and the middle two toes turned inward. The female resembles the male but is smaller and has a narrower chestband and a shorter tail. Additionally, the female Long-tailed Ground Roller loses its tail while nesting. Juveniles of both sexes are duller in plumage than the adult female, particularly in the black bands on the chest, neck, and eye.
This ground roller is largely a silent species except during the breeding season. Its vocalizations include a "hooting" sound, a "popping" tu-tuc, and a soft boo sound. The low-pitched "hooting" is given from a perch 2 to 6 m (6.6 to 19.7 ft) above the ground at dusk or at night. The sound carries for a distance of at least 200 metres (656.2 ft) and it has been suggested that this song attracts a mate or is used to defend a territory. The bird pumps its tail while giving this call. The territorial call is a series of soft "boo" notes, typically coming in sets of six to ten and descending near the end. Another territorial call has been described as a series of chuckling tu-tuc sounds lasting between 10 and 40 seconds that occasionally ends in a loud snapping sound produced by the wings. This call is given when birds are close to each other and on the ground or low perches and does not carry over long distances. The use of wing-snapping to produce a sound is a rare phenomenon in birds, and only one other family in the order Coraciiformes
, the todies
, is known to do it. Low "gu" notes are given by mates as they come in contact with each other.
The Long-tailed Ground Roller is endemic to the island nation of Madagascar
. It inhabits a narrow strip of suitable habitat by the coast in the southwestern part of the island. This strip is bordered by the Mangoky River
in the north, the Fiherenana River in the south, and lowland hills in the east. It totals about 10500 square kilometres (4,054.1 sq mi) in area; however, the species is extremely uncommon within its range and occurs at densities of about 0.008 to 0.1 per 10000 square metres (107,639.1 sq ft). This area ranges in elevation from sea level to 100 metres (328.1 ft). It does not migrate
, though it is believed to disperse across a broader stretch of habitat outside of the breeding season.
This species' prime habitat is a mix of sub-arid thorn-scrub and deciduous woodland. This area only averages 500 millimetres (19.7 in) of water a year and is covered in sandy soil. The dominant plants in this spiny forest
belong to the cactus-like Didiereaceae
family (especially Didierea madagascariensis
) and more tree-like Euphorbiaceae
family (especially Euphorbia stenoclada
). Baobab
trees are also prevalent. It formerly was believed that the Long-tailed Ground Roller preferred undisturbed forest habitat, despite tolerating small amounts of disturbance. However, recent studies have concluded that it actually prefers degraded habitat. However, shade is necessary and the species is not found in deforested habitat or on the shadeless dunes prevalent in its range.
Long-tailed Ground Rollers use both their bill and feet to excavate a burrow in consolidated sand and construct their nest at the end of it. The burrow, always constructed away from grassy vegetation, is downward-sloping. The burrow is between 0.8 and 1.2 m (2.6 and 3.9 ft) long and has a diameter of 8 centimetres (3.1 in). The end of the burrow widens into a 20 centimetres (7.9 in) wide chamber with a shallow floor covered in dry leaves and earthy pellets. When digging its nest, the Long-tailed Ground Roller occasionally walks underneath a low branch, tilts its head upwards, and, while remaining motionless, releases a rising crescendo of its "tu-tuc" calls. At the height of the crescendo the bird breaks off its call and flies upwards onto the branch while producing a "ripping and crackling sound" with its wingbeats. From the perch the bird releases a stream of "boo" notes. It is believed that this display is part of a courtship ritual.
Between October and January, peaking in November, the species lays two to four eggs, normally two. The eggs are smooth and white. After the young fledge, they still live in a family group of four to five birds for an unknown period of time before the family disperses.
by the IUCN due to ongoing habitat destruction and a decline in the quality of remaining habitat. It is believed to be the most threatened species of ground roller. Thirty percent of its already small habitat area was degraded between the mid-1970s and 2000. Slash-and-burn agriculture, charcoal production, logging, and cattle grazing contributed to the loss of habitat. As of 2011, no reserves protect any portion of its habitat, and as a result its habitat has been described as the area of Madagascar most in need of conservation efforts. It is also threatened by both hunting and egg-collecting. In addition to humans, dogs hunt this species and the introduced black rat
is believed to be a nest predator. This species is capable of tolerating some habitat disturbance, but requires a suitable amount of shade and leaf litter to continue living in the area. The estimated population of the Long-tailed Ground Roller is between 9,500 and 32,700 birds and declining.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of 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...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Brachypteraciidae, and is placed in the monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Uratelornis. This bird is endemic to arid spiny forest
Madagascar spiny thickets
The Madagascar spiny thickets is an ecoregion in Madagascar. The vegetation type is found on poor substrates with low, erratic winter rainfall. An estimated 14,000 to is covered with this habitat, all in the southwest of the country...
s near the coast in southwestern Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. It occurs in extremely low population densities throughout its habitat. It requires shade and a deep layer of leaves in its habitat, and it is absent from parts of the spiny forest lacking these traits. It has no recognized subspecies, and its closest relative is believed to be the Scaly Ground Roller. The Long-tailed Ground Roller is the only ground roller to definitively display sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, or differences in plumage or size between sexes. It is a medium-sized bird with a plump silhouette and a long tail. The upperparts are dark brown with black streaks while the underparts are light gray. The white throat is framed by black malar stripes and a black breastband, while a white stripe is present at the base of the bill. Sky blue feathers are visible at the edge of the wings and the tail. Calls are rarely made outside of the breeding season, though multiple territorial calls are made.
These ground rollers feed primarily on invertebrates, ranging from worms to butterflies. The bird searches through deep leaf litter for its prey or waits attentively for an opportunity. Its wings are relatively weak, so the ground roller primarily uses its strong legs to run through its habitat. The Long-tailed Ground Roller is a monogamous species, and defends a territory during the breeding season of October to February. The species digs a tunnel in the sand, at the end of which is a wider chamber where it makes its nest out of leaves and earthy pellets. Two to four eggs are laid. After the chicks fledge, the birds continue living in family groups for an unknown period of time after the breeding season before dispersing across the habitat.
This species is classified as Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
, and is threatened by habitat destruction. The arid spiny forests in which it lives are unprotected by the Madagascan government, and as such the species is losing habitat to slash-and-burn agriculture, charcoal collection, and logging. The species is also hunted by the native peoples of Madagascar.
Taxonomy
The Long-tailed Ground Roller was described by British banker and naturalist Walter RothschildWalter Rothschild, 2nd Baron Rothschild
Lionel Walter Rothschild, 2nd Baron Rothschild, Baron de Rothschild FRS , a scion of the Rothschild family, was a British banker, politician, and zoologist.-Biography:...
in 1895. Rothschild described the species as Uratelornis chimaera, and published his description in the periodical of his private museum, Novitates Zoologicae. The Long-tailed Ground Roller is currently placed in the ground roller family. However, until recently the ground rollers, Cuckoo Roller, and 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 were all placed in a single family in which each of the three groups formed a subfamily. In 1971 Joel Cracraft proposed erecting a separate family for the ground rollers based on dramatic differences in behavior, plumage, and post-cranial anatomy between the groups. This position is supported by DNA evidence, which also removed the Cuckoo Roller from the group. It has been suggested but not widely accepted that the ground rollers are closely related to the puffbird
Puffbird
The puffbirds and their relatives in the near passerine family Bucconidae are tropical birds breeding from South America up to Mexico.They are related to the jacamars, but lack the iridescent colours of that family. They are mainly brown, rufous or grey, with large heads and flattened bills with a...
s and jacamar
Jacamar
The jacamars are a family, Galbulidae, of near passerine birds from tropical South and Central America, extending up to Mexico. The order contains five genera and 18 species...
s. It is believed that the ancestor of the Long-tailed Ground Roller was an arboreal roller that invaded Madagascar from Africa and developed a terrestrial lifestyle before moving from the rainforests into the Long-tailed Ground Roller's arid scrubland. The adaptations required for the ancestral Long-tailed Ground Roller to inhabit scrubland led Rothschild to create the monotypic genus Uratelornis for the species in his description. No fossils have been found for this genus. Recent genetic analysis suggests that this species' closest relative is the Scaly Ground Roller. This species has no subspecies.
Description
The Long-tailed Ground Roller is the only ground roller to definitively display sexual dimorphismSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
. It is highly distinctive from a distance due to its long tail and plump silhouette. The bird is 34 to 47 cm (13.4 to 18.5 in) long, although its tail can contribute up to 30 centimetres (11.8 in) of the length. This tail is the longest of the ground rollers. This ground roller has short wings and long, pinkish-brown legs. The male has a sandy buff crown and dark brown upperparts with black streaks. Its supercilium
Supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...
is a pale buff color, while the ear-coverts are brown. The eyes are brown and the short and stout beak
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...
is black. Its tongue is long with a brush-like tip to help it collect insects. A white stripe is present from the base of the bill and is surrounded by brown and black malar stripes. These malar stripes and the black breastband frame a white throat. The tail has 15 to 20 dark brown bars marking it, while the outer retrices are sky blue. This sky blue is also present on the wing-coverts. In flight, its two black and white bands on the primaries and secondaries are conspicuous. The underparts are a light gray, and the breast white. The toes are zygodactylous, with the first and fourth toes turned outwards and the middle two toes turned inward. The female resembles the male but is smaller and has a narrower chestband and a shorter tail. Additionally, the female Long-tailed Ground Roller loses its tail while nesting. Juveniles of both sexes are duller in plumage than the adult female, particularly in the black bands on the chest, neck, and eye.
This ground roller is largely a silent species except during the breeding season. Its vocalizations include a "hooting" sound, a "popping" tu-tuc, and a soft boo sound. The low-pitched "hooting" is given from a perch 2 to 6 m (6.6 to 19.7 ft) above the ground at dusk or at night. The sound carries for a distance of at least 200 metres (656.2 ft) and it has been suggested that this song attracts a mate or is used to defend a territory. The bird pumps its tail while giving this call. The territorial call is a series of soft "boo" notes, typically coming in sets of six to ten and descending near the end. Another territorial call has been described as a series of chuckling tu-tuc sounds lasting between 10 and 40 seconds that occasionally ends in a loud snapping sound produced by the wings. This call is given when birds are close to each other and on the ground or low perches and does not carry over long distances. The use of wing-snapping to produce a sound is a rare phenomenon in birds, and only one other family in the order Coraciiformes
Coraciiformes
The Coraciiformes are a group of usually colorful near passerine birds including the kingfishers, the Hoopoe, the bee-eaters, the rollers, and the hornbills...
, the todies
Tody
The todies are a family, Todidae, of Caribbean birds in the order Coraciiformes, which also includes the kingfishers, bee-eaters and rollers. The family has one genus, Todus...
, is known to do it. Low "gu" notes are given by mates as they come in contact with each other.
Distribution and habitat
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. It inhabits a narrow strip of suitable habitat by the coast in the southwestern part of the island. This strip is bordered by the Mangoky River
Mangoky River
The Mangoky River is a 564-kilometer-long river in Madagascar. It rises in the Central Highlands of Madagascar just east of the city of Fianarantsoa...
in the north, the Fiherenana River in the south, and lowland hills in the east. It totals about 10500 square kilometres (4,054.1 sq mi) in area; however, the species is extremely uncommon within its range and occurs at densities of about 0.008 to 0.1 per 10000 square metres (107,639.1 sq ft). This area ranges in elevation from sea level to 100 metres (328.1 ft). It does not migrate
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...
, though it is believed to disperse across a broader stretch of habitat outside of the breeding season.
This species' prime habitat is a mix of sub-arid thorn-scrub and deciduous woodland. This area only averages 500 millimetres (19.7 in) of water a year and is covered in sandy soil. The dominant plants in this spiny forest
Madagascar spiny thickets
The Madagascar spiny thickets is an ecoregion in Madagascar. The vegetation type is found on poor substrates with low, erratic winter rainfall. An estimated 14,000 to is covered with this habitat, all in the southwest of the country...
belong to the cactus-like Didiereaceae
Didiereaceae
Didiereaceae is a small family of just four genera and 11 species of flowering plants endemic to south and southwest Madagascar, where they form an important component of the Madagascar spiny forests.-Description:...
family (especially Didierea madagascariensis
Didierea madagascariensis
Didierea madagascariensis, commonly known as the Octopus tree, is a species of Didiereaceae endemic to the spiny thickets of Madagascar. It was first described scientifically by the French botanist Henri Ernest Baillon in 1880. The type species of the genus Didierea, it is a densely spiny succulent...
) and more tree-like Euphorbiaceae
Euphorbiaceae
Euphorbiaceae, the Spurge family are a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti....
family (especially Euphorbia stenoclada
Euphorbia stenoclada
Euphorbia stenoclada is a species of plant in the Euphorbiaceae family. It is endemic to Madagascar. Its natural habitats are subtropical or tropical dry forests, subtropical or tropical dry shrubland, and rocky areas. It is threatened by habitat loss....
). Baobab
Baobab
Adansonia is a genus of eight species of tree, six native to Madagascar, one native to mainland Africa and the Arabian Peninsula and one to Australia. The mainland African species also occurs on Madagascar, but it is not a native of that island....
trees are also prevalent. It formerly was believed that the Long-tailed Ground Roller preferred undisturbed forest habitat, despite tolerating small amounts of disturbance. However, recent studies have concluded that it actually prefers degraded habitat. However, shade is necessary and the species is not found in deforested habitat or on the shadeless dunes prevalent in its range.
Ecology and behavior
The Long-tailed Ground Roller is a shy and elusive bird. If seen, it either freezes or runs away. Due to its short wings, the species rarely flies, but it is a powerful runner. While largely terrestrial, it roosts in low trees and bushes and sings from low perches. The Long-tailed Ground Roller is a solitary species outside of the breeding season. It is diurnal, though, unusually for a ground roller, it occasionally forages at night. When calling, this species bobs its head and raises its tail. The Long-tailed Ground Roller also raises its tail when it is excited.Diet
This species forages almost exclusively from the ground. It alternates between attentively waiting for prey and actively searching for it by rummaging through deep leaf litter. It eats invertebrates and occasionally small vertebrates. This ground roller eats a wide range of invertebrates, including ants, beetles, butterflies, caterpillars, cockroaches, grasshoppers, woodlice, and worms. Despite the Long-tailed Ground Roller's poor flying abilities, it has been seen catching butterflies in midair.Reproduction
The breeding season coincides with the rainy season, lasting from October to January. During the breeding season this species abandons its solitary habits to pair with another Long-tailed Ground Roller, to which it remains monogamous. Males also form territories during the breeding season, defending their area with territorial calls. These calls are given from a perch up to 6 metres (19.7 ft) off of the ground for an hour after sunrise and occasionally throughout the day and night. Males have been observed feeding the female during courtship.Long-tailed Ground Rollers use both their bill and feet to excavate a burrow in consolidated sand and construct their nest at the end of it. The burrow, always constructed away from grassy vegetation, is downward-sloping. The burrow is between 0.8 and 1.2 m (2.6 and 3.9 ft) long and has a diameter of 8 centimetres (3.1 in). The end of the burrow widens into a 20 centimetres (7.9 in) wide chamber with a shallow floor covered in dry leaves and earthy pellets. When digging its nest, the Long-tailed Ground Roller occasionally walks underneath a low branch, tilts its head upwards, and, while remaining motionless, releases a rising crescendo of its "tu-tuc" calls. At the height of the crescendo the bird breaks off its call and flies upwards onto the branch while producing a "ripping and crackling sound" with its wingbeats. From the perch the bird releases a stream of "boo" notes. It is believed that this display is part of a courtship ritual.
Between October and January, peaking in November, the species lays two to four eggs, normally two. The eggs are smooth and white. After the young fledge, they still live in a family group of four to five birds for an unknown period of time before the family disperses.
Conservation
The Long-tailed Ground Roller has been classified as VulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
by the IUCN due to ongoing habitat destruction and a decline in the quality of remaining habitat. It is believed to be the most threatened species of ground roller. Thirty percent of its already small habitat area was degraded between the mid-1970s and 2000. Slash-and-burn agriculture, charcoal production, logging, and cattle grazing contributed to the loss of habitat. As of 2011, no reserves protect any portion of its habitat, and as a result its habitat has been described as the area of Madagascar most in need of conservation efforts. It is also threatened by both hunting and egg-collecting. In addition to humans, dogs hunt this species and the introduced black rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...
is believed to be a nest predator. This species is capable of tolerating some habitat disturbance, but requires a suitable amount of shade and leaf litter to continue living in the area. The estimated population of the Long-tailed Ground Roller is between 9,500 and 32,700 birds and declining.