|Dollarbird at San Diego Zoo|
Eurystomus contains four broad-billed species, which breed in Africa, Asia and Australasia. Two species are restricted to Africa, one of which, the broad-billed roller, is migratory. The oriental dollarbird has a large distribution ranging from India to Japan and Australia and it too, is migratory over the northern and southern extremes of its range. The final species, the azure dollarbird, is endemic to the Moluccas in Indonesia. In general they are open country foragers, occurring in woodland, savanna and farmland. The azure dollarbird and the broad-billed roller are both associated with rainforests but nevertheless require open areas in which to forage.
The species of the genus Eurystomus vary from the other genus of rollers, Coracias, in having proportionally longer wings and shorter legs. These morphological differences are reflected in differences of foraging techniques. Coracias rollers forage from a fixed perch and take prey by swooping down onto it on the ground, while the faster and more agile Eurystomus rollers catch their prey on the wing. Unlike the species of the genus Coracias, they do not perform the "rolling" display which gives the family its common name.
- Blue-throated roller (Eurystomus gularis)
- Broad-billed roller (Eurystomus glaucurus)
- Oriental dollarbird (Eurystomus orientalis)
- Azure dollarbird (Eurystomus azureus)
- William Somerville Orr (1855). Orr's circle of the sciences: a series of treatises on the principles of science, with their application to practical pursuits. p. 517.
- Fry, C (2001), "Family Coraciidae (Rollers)", in del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi, Handbook of the Birds of the World. Volume 6, Mousebirds to Hornbills, Barcelona: Lynx Edicions, pp. 342–369, ISBN 978-84-87334-30-6
- Kingfishers, Bee-eaters and Rollers by Fry, Fry and Harris, ISBN 0-7136-8028-8
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