Cuckoo-roller
Encyclopedia
The Cuckoo Roller is the only bird
in the family Leptosomatidae, which is usually considered to be within the order Coraciiformes
, which also includes the kingfisher
s, bee-eater
s and roller
s. However, the position of this family is not very clear. Morphological evidence may suggest a placement within or near to Falconiformes
. In the rather comprehensive DNA
study by Hackett et al. this is one of only two birds – besides the Hoatzin
– of which the position is not clear, although it seems to be at the root of a group that contains the Trogoniformes, Bucerotiformes, Piciformes
and Coraciiformes
.
It is also commonly known to English speakers by its French
name Courol.
It is a medium-large bird, inhabiting forests and woodlands in Madagascar
and the Comoro Islands
. There are three subspecies
; the nominate L. d. discolor is found in Madagascar and Mayotte Island, L. d. intermedius on Anjouan
, and L. d. gracilis of Grand Comoro. Based on its smaller size, differences in the plumage
, and minor difference in the voice, the last of these is sometimes considered a separate species, the Comoro Cuckoo Roller (L. gracilis).
are generally reported as resembling a dull female, but at least juveniles of L. d. gracilis are sexually dimorphic, and it is possible this also applies to the other subspecies. The bill
is stout and the eyes set far back in the face. The legs and feet are small, and the feet have an unusual structure which has confused many ornithologists, but is now thought to be zygodactylous.
The diet of the Cuckoo Roller is not well known, but a 1931 expedition found that chameleon
s and insect
s, particularly locusts and caterpillars are important food items. Stomach have often been found lined with the hairs of caterpillars, and other prey taken include grasshoppers, cicada
s, stick insects and gecko
s. The principal foraging technique is to perch motionless watching for prey, then to make a quick sally towards the prey when observed. They will also forage from the air. Prey is caught in the large bill and dispatched by beating it against a branch.
Very few studies have investigated the breeding biology of the Cuckoo Roller. It has been described in the past as a polygamous breeder, but there is no evidence for this. The nest
is located in tall trees, 4–6 m off the ground, in natural cavities. No lining is placed inside the cavity, the white eggs are laid directly on the bottom. The usual clutch size is around four eggs. Incubation
is performed by the female only, with the male feeding her while she is in the nest. The incubation period is about 20 days, after which fluffy chicks are born. Chicks remain in the nest for 30 days before fledging
.
The Cuckoo-roller is described as being very tame, and it is generally not disturbed by the inhabitants of Madagascar, many of which have legends and myths about the species. It is regarded by many as a good omen and the harbinger of clear weather. It tendency to be seen in pairs also has brought about an association with couples and love. The species is not generally hunted and has proven resistant to habitat change that has threatened other native birds, and is considered least concern
by the IUCN.
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 Leptosomatidae, which is usually considered to be within 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...
, which also includes the kingfisher
Kingfisher
Kingfishers are a group of small to medium sized brightly coloured birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species being found in the Old World and Australia...
s, bee-eater
Bee-eater
The bee-eaters are a group of near-passerine birds in the family Meropidae. Most species are found in Africa and Asia but others occur in southern Europe, Australia, and New Guinea. They are characterised by richly coloured plumage, slender bodies, and usually elongated central tail feathers...
s 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. However, the position of this family is not very clear. Morphological evidence may suggest a placement within or near to Falconiformes
Falconiformes
The order Falconiformes is a group of about 290 species of birds that comprises the diurnal birds of prey. Raptor classification is difficult and the order is treated in several ways.- Classification problems :...
. In the rather comprehensive DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
study by Hackett et al. this is one of only two birds – besides the Hoatzin
Hoatzin
The Hoatzin , also known as the Hoactzin, Stinkbird, or Canje Pheasant, is a species of tropical bird found in swamps, riverine forest and mangrove of the Amazon and the Orinoco delta in South America...
– of which the position is not clear, although it seems to be at the root of a group that contains the Trogoniformes, Bucerotiformes, Piciformes
Piciformes
Nine families of largely arboreal birds make up the order Piciformes, the best-known of them being the Picidae, which includes the woodpeckers and close relatives...
and 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...
.
It is also commonly known to English speakers by its French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
name Courol.
It is a medium-large bird, inhabiting forests and woodlands in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
and the Comoro Islands
Comoro Islands
The Comoros Islands form an archipelago of volcanic islands situated off the south-east coast of Africa, to the east of Mozambique and north-west of Madagascar. They are divided between the sovereign state of Comoros and the French overseas department of Mayotte...
. There are three subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
; the nominate L. d. discolor is found in Madagascar and Mayotte Island, L. d. intermedius on Anjouan
Anjouan
Anjouan is an autonomous island, part of the Union of Comoros. The island is located in the Indian Ocean. Its capital is Mutsamudu and its population as of 2006 is about 277,500. The total area of the island is 424 sq. kilometers Anjouan (also known as Ndzuwani or Nzwani) is an autonomous island,...
, and L. d. gracilis of Grand Comoro. Based on its smaller size, differences in the plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
, and minor difference in the voice, the last of these is sometimes considered a separate species, the Comoro Cuckoo Roller (L. gracilis).
Description
The Cuckoo Roller has a total length of 40–50 cm (16–20 in), with nominate being largest, and L. d. gracilis smallest. Unlike the true rollers and ground rollers, where the sexes have identical appearance, the Cuckoo Roller is sexually dichromatic. Males have a mostly velvety grey chest and head, changing gradually to white on the remaining underparts (demarcation between grey and white stronger in L. d. gracilis). The back, tail, and wing-coverts are dark iridescent green with a purplish tinge (especially on the wing-coverts), and the crown and eye-stripe are black. Females are mostly brown with strongly dark-spotted pale underparts (less spotting in L. d. gracilis). JuvenilesJuvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
are generally reported as resembling a dull female, but at least juveniles of L. d. gracilis are sexually dimorphic, and it is possible this also applies to the other subspecies. The 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...
is stout and the eyes set far back in the face. The legs and feet are small, and the feet have an unusual structure which has confused many ornithologists, but is now thought to be zygodactylous.
The diet of the Cuckoo Roller is not well known, but a 1931 expedition found that chameleon
Chameleon
Chameleons are a distinctive and highly specialized clade of lizards. They are distinguished by their parrot-like zygodactylous feet, their separately mobile and stereoscopic eyes, their very long, highly modified, and rapidly extrudable tongues, their swaying gait, the possession by many of a...
s and 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, particularly locusts and caterpillars are important food items. Stomach have often been found lined with the hairs of caterpillars, and other prey taken include grasshoppers, cicada
Cicada
A cicada is an insect of the order Hemiptera, suborder Auchenorrhyncha , in the superfamily Cicadoidea, with large eyes wide apart on the head and usually transparent, well-veined wings. There are about 2,500 species of cicada around the world, and many of them remain unclassified...
s, stick insects and gecko
Gecko
Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 cm to 60 cm....
s. The principal foraging technique is to perch motionless watching for prey, then to make a quick sally towards the prey when observed. They will also forage from the air. Prey is caught in the large bill and dispatched by beating it against a branch.
Very few studies have investigated the breeding biology of the Cuckoo Roller. It has been described in the past as a polygamous breeder, but there is no evidence for this. The nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
is located in tall trees, 4–6 m off the ground, in natural cavities. No lining is placed inside the cavity, the white eggs are laid directly on the bottom. The usual clutch size is around four eggs. Incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
is performed by the female only, with the male feeding her while she is in the nest. The incubation period is about 20 days, after which fluffy chicks are born. Chicks remain in the nest for 30 days before fledging
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
.
Relations with humans
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
by the IUCN.
External links
- Cuckoo Roller videos, photos & sounds on the Internet Bird Collection