Hoopoes
Colorful, numerous and attractive birds rollers and hoopoes have attracted nuch attention, principally because of the recently discovered mass-emigration of hundreds of thousands of European rollers from East Africa. Cinnamon rollers, whose diet consists of swarming termites, andGreen wood-hoopoes, who have “helpers”at the nest, have also attracted attention.
Rollers are not particularly closely allied with hoopoes. Appearances and ways of life are very different, yet there are underlying, affinities of breeding and biology and structure: 22 of the 25 species belonging to these four families breed in the Afro-tropical region and the two most northerly breeding species, European roller and hoopoe, are of immediate descent from relatives in the tropics.
Rollers are so-called because of the spec-tabular tumbling courtship flight of “true “rollers (Curacies) and of broad-billed rollers (Eurystomus). The former spend much time
Aloft, defending their territory with raucous calls and rolling flight: but they feed mainly on the ground, dropping onto small animals from a perch. Broad-billed rollers, by con-trust, feed on the wing. For most of the day pair sits on treetops, eating little, and aggressively chasing other birds away ; burin the late afternoon up to 20o gather. Dramatically losing their aggressiveness to feed on winged termites. With pointed, quite long wings, large head, short neck and thickset body, they have a fast, wheeling and swooping flight and resemble falcons or huge swifts. One bird can cat up to Boo termites (half the weight of the bird itself) in the you minutes before dusk. One African species is resident in rain forests; another Isa migrant within the tropical savannas and between Africa and Madagascar. The Oriental species is called dollar-bird because of the coin-sized white “windows” in its wing tips. And migrates between Australia and New Guinea.
All Corneas rollers are also strongly migratory. European rollers enter Africa in September, when the closely allied and verisimilar Abyssinian rollers are also migrating up to L000km (600mi) southwards within the northern tropics. But European rollers travel ten times as far, and winter mainly in arid country in Kenya, Tanzania and Namibia. In the first few days of April, huge numbers concentrate in eastern Tanzania, and fly together in a narrow coastal corridor through Kenya and Somalia, where thousands can be seen together, evenly dispersed in the sky from horizon to horizon.
All rollers appear to be monogamous, highly territorial, hole-nesters. Apart from the spectacular rolling flight, the breeding biology of European and Indian rollers is not unusual. Most African species are curiously ill-known, considering how common and eminently stud able the birds are. Madagascan ground rollers are even less well-known; they seem to be mainly active at twilight, feeding entirely on the ground, and nesting in holes in open ground (Long-tailed ground roller), around forest tree roots (Pita-like and Crosslet’s ground rollers). Orin trees (Short-legged ground roller). There is a strong native tradition that these birds hibernate in the dry season.
The Cuckoo-roller is restricted to Madagascar and the Comoro islands. And may well be more closely related to “true” rollers than are the ground rollers. Cuckoo-rollers have the proportions and flight character-is tics of “true” rollers but they seek their food neither in the air nor on the ground, but in the upper story of large forest trees. Chameleons appear to be a staple food item and it is likely that Cuckoo-rollers specialize on them.
Wood-hoopoes comprise one of the very few bird families confined to Africa. Smaller species are rather solitary, but larger ones are gregarious, in parties of 5-1 2, and make themselves highly conspicuous by period-icily interrupting foraging to indulge in noisy mutual displays. Each bird cackles vociferously (they are called kakelaars inAfricaans, or cacklers), and with each call the head is exaggeratedly bowed and the tail raised high. After a few seconds, they all fly from the nest tree and quietly resume foraging, probing into hark crevices with their long slender bills and often clinging below horizontal limb or crosswise on a trunk. The bill is straight in some species, down-curved in others, and in the scimitar-greatly down curved, bending through 90degrees. “Cackling” functions to maintain the identity and cohesion of the group, which is more or less an extended family of parents, helpers and young. Studies in Kenya show that one advantage to the helper, which foregoes breeding in order to help at another adult’s nest, is that the helper forms bonds with the young it helps to raise and in a subsequent nesting season those young will assist the former helper, improving its breeding success.
Best known of all these birds is the hoopoe, with a vast breeding range in three continents. Being conspicuous and common in gardens and cultivated land, it has a special place in folklore and people’s affections.
Hoopoes are small-headed, short-legged perching and ground birds. They forage by walking over turf, probing with their long slender bill for grubs and, like wood hoopoes, taking insects from fissured barking trees. They fly readily, with irregular, butterfly-like beats of rounded black wings with white bars across the flight feathers and on perching often momentarily fan the crest. Races vary in the amount of white in the wing, and the depth of body color. Southern African hoopoes are reddish, with little white in the wing, and being readily distinguished in the field from wintering Eurasian migrants, they were formerly held to be a distinct species. Nests are scantily-lined cavities in termite-mounds, old woodpecker holes, rough stone walls, drainpipes or clefts in trees; the entrance is narrow, so that the bird has to squeeze in, and the whole itself fetid. Young are downy. They have five methods of defense: by spraying excreta; hissing; poking upward with the bill: striking with. One wing; and a stinking excretion of the preen gland. Adult hoopoes react to overhead birds of prey by flattening them-selves against the ground, with wings and tail spread conspicuously and bill pointing straight up.