The word roller can mean:-

• Some species of birds: see hereinunder.
• A farm and gardening tool: see roller (agricultural tool).
• A heavy machine used in a steel mill: see hot rolling and cold rolling.

The Rollers are an Old World family of near passerine birds. They resemble crows in size and build, but are more closely 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, usually catching their prey in the air. They often perch prominently whilst hunting, like giant shrikes. The group gets its name from the aerial acrobatics some of these birds perform.

These are birds of warm climates. They nest in an unlined tree-hole, and lay 2-4 eggs.

The eleven species are:

Genus Coracias

• European Roller Coracias garrulus
• Abyssinian Roller Coracias abyssinica
• Lilac-breasted Roller Coracias caudata
• Racquet-tailed Roller Coracias spatulata
• Rufous-crowned Roller Coracias noevia
• Indian Roller Coracias benghalensis
• Temminck's Roller Coracias temminckii
• Blue-bellied Roller Coracias cyanogaster

Genus Eurystomus

• Broad-billed Roller Eurystomus glaucurus
• Blue-throated Roller Eurystomus gularis
• Azure Roller Eurystomus azureus
• Dollarbird Eurystomus orientalis

Reference

• Kingfishers, Bee-eaters and Rollers by Fry, Fry and Harris, ISBN 0-7136-8028-8