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.

Unlike the species of the genus Coracias, they do not perform the "rolling" display which gives the family its common name.

[2] The genus Eurystomus was introduced in 1816 by the French ornithologist Louis Pierre Vieillot to accommodate the Oriental dollarbird.

[5] A molecular phylogenetic study by Ulf Johansson and collaborators published in 2018 found that the azure dollarbird (Eurystomus azureus) was nested in a clade containing subspecies of the Oriental dollarbird (Eurystomus orientalis).