Rollers - Multicoloured Sky Warriors
For many people visiting African game parks to see large mammals, the first bird which is likely to attract their admiration is the Lilac-breasted Roller. Few photographers can resist an atempt to capture the bird on film. This striking, dove-sized bird is common in savanna and open woodland, where it perches conspicuously on outermost branch tips, termite mounds and tree tops. With its electric blue wings, pink and powder blue underparts, and elongated tail feathers it is indeed a magnificent creature. Seeing this bird swoop from its perch in pursuit of a flying insect is a dazzling sight.
Rollers are closely related to both kingfishers and bee-eaters in the order Coraciiformes. There are 12 species, within two distinct genera - Coracias and Eurystomus. Africa is home to seven species, including the migratory European Roller, which breeds in the Mediterranean, Eastern Europe and Asia. Only the European Roller occurs in Eurasia, while the Indian Roller occurs mostly in south-east Asia. Three species are found in Indonesia, including the wide-ranging Dollarbird which migrates south to Australia. The family has no representatives in the Americas where Neotropical puffbirds, motmots and jacamars are ecological counterparts.
Rock and Roll Display
The family is named for the rolling display flight of several species. Birds such as the Lilac-breasted and Abyssinian Rollers perform dramatic flights which advertise their territory and form part of courtship and pair-bonding. In some cases, the flights are aggressive actions directed at interlopers, including rival pairs and human beings. In these flights, the roller flies high into the sky, tilts forward, and barrels headlong towards the ground. At first, the wings beat powerfully to gain momentum and then the bird rocks its body from side to side, while keeping its head straight and still. The wings rotate this way and that, several times per second as the roller hurtles towards the ground. Just as it appears out of control and about to crash to earth, the roller levels out and slows down before flying upward again to repeat the extraordinary feat. The vibrating wings create a discernible noise and the bird may let out a shriek as it heads groundward. The display flight is not the only aggressive side to the rollers for they frequently harass all manner of other creatures including predators such as eagles and even leopards. Hardworking woodpeckers are not infrequently chased from their nest holes which are then taken over by the rollers.
Although not related in any way, some people liken rollers to small colourful crows. Their proportions are certainly not dissimilar, and neither is their aggressive streak. Perhaps the greatest affinity between the two unrelated families, however, is their lack of musical ability. Like crows, rollers can do little more than utter harsh, grating notes. They frequently shriek or bark when alarmed or in pursuit of a rival.
Sit-and-wait or on-the-wing
With a powerful, hook-tipped bill, rollers are efficient predators of large insects, scorpions, lizards and other small vertebrates. The hunting strategy of Coracias rollers is to take up a good vantage point and wait for something to come within striking distance. Prey is then captured by a pounce and seized in the large bill. Small items are simply tossed upwards and swallowed but bigger prey is smacked repeatedly against a branch or the ground, before being consumed. On one occasion, I watched a European Roller take over twenty minutes to mash and swallow a fully grown toad. On another, I watched one Lilac-breasted Roller present its mate with a large scorpion which it had softened with repeated beating.
Members of the genus Eurystomus - such as the Cinnamon Roller - obtain most of their food on the wing. Termites, dragonflies and beetles are captured after an aerial chase. In the case of the Cinnamon Roller, almost all feeding takes place in the last hour or so of daylight, with the rest of the day spent perching on an exposed branch.
All rollers lay their white eggs (one to three) in a tree hole or earthen bank. In many cases woodpeckers are evicted from their own chambers and battles with other hole nesting birds, such as small owls and kingfishers, are not uncommon. Both sexes appear to incubate and provide for the young which leave the nest hole after about 25-30 days. Despite their conspicuous habits and colourful plumage, few detailed studies have been conducted on rollers and much information is still required on their ecology.
&Beyond's Roller Hotspots
A variety of rollers can be seen at most &Beyond properties, with up to four species present at Londolozi, Bongani and Ngala during the summer months.
- Duncan Butchart -
Posted: Birds by CC Africa, Date: 21 November 2006