Eurystomus
Encyclopedia
Eurystomus is a genus
of the roller
, one of the two genera in that family of bird
s. 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 ranging from India to Japan and Australia. It too is migratory over the northern and southern extremes of its range. The final species, the Azure Roller, is endemic to Moluccas in Indonesia. In general they are open country foragers, occurring in woodland, savanna and farmland. Two species, the Azure Roller and the Cinnamon Roller are associated with rainforests but nevertheless require open areas in which to forage.
The Eurystomus vary from the other genus of rollers, Coracias
in having proportionally longer wings and shorter legs. These morphological differences reflect differences in foraging technique, whereas Coracias rollers forage from a fixed perch and take prey by swooping down onto it on the ground, the faster and more agile Eurystomus rollers catch their prey on the wing. Unlike the Coracias they do not perform the "rolling" display which gives the family its common name.
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...
of 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...
, one of the two genera in that family 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...
s. It contains four broad-billed species, which breed in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
and Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...
. Two species are restricted to Africa, one of which, the Cinnamon Roller, 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...
. The Dollarbird
Dollarbird
The Oriental Dollarbird , also known as the Dollar Roller, is a bird of the roller family, so named because of the distinctive blue coin-shaped spots on its wings....
has a large distribution ranging from India to Japan and Australia. It too is migratory over the northern and southern extremes of its range. The final species, the Azure Roller, is endemic to Moluccas in Indonesia. In general they are open country foragers, occurring in woodland, savanna and farmland. Two species, the Azure Roller and the Cinnamon Roller are associated with rainforests but nevertheless require open areas in which to forage.
The Eurystomus vary from the other genus of rollers, Coracias
Coracias
Coracias is a genus of the rollers, an Old World family of near passerine birds related to the kingfishers and bee-eaters. They share the colourful appearance of those groups, blues and browns predominating. The two inner front toes are connected, but not the outer one.These are insect eaters,...
in having proportionally longer wings and shorter legs. These morphological differences reflect differences in foraging technique, whereas Coracias rollers forage from a fixed perch and take prey by swooping down onto it on the ground, the faster and more agile Eurystomus rollers catch their prey on the wing. Unlike the Coracias they do not perform the "rolling" display which gives the family its common name.
Species
- Broad-billed RollerBroad-billed RollerThe Broad-billed Roller, Eurystomus glaucurus, is a member of the roller family of birds which breeds across tropical Africa and Madagascar in all but the driest regions. It is a wet season breeder, which migrates from the northern and southern areas of its range towards the moister equatorial...
or Broad-billed Roller Eurystomus glaucurus - Blue-throated RollerBlue-throated RollerThe Blue-throated Roller is a species of bird in the Coraciidae family.It is found in Angola, Benin, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Ivory Coast, Equatorial Guinea, Gabon, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Nigeria, Sierra...
Eurystomus gularis - Azure Dollarbird Eurystomus azureus
- Oriental Dollarbird Eurystomus orientalis