African Wildlife and Environment Issue 65

BIRDING

BIRDING

They first dig with the bill and later remove loose sand with a bicycling action of feet. A new burrow is excavated each year. The nesting burrow is more or less straight and horizontal, up to at least one metre long and 60 mm in diameter, terminating in an unlined oval nest chamber. These breeding tunnels are well buffered against outside temperate changes, making incubation less onerous. However they are not impervious to marauding monitors and mambas. The colonies on flat ground may be raided by jackals and Southern Ground Hornbills, nevertheless the impact by natural predation seems to be negligible. These nest chambers accumulate a blackish carpet of insect sclerites from trodden-down pellets and dropped insects, and smell strongly of ammonia. They breed from September to November. A usual clutch is three elliptical, smooth glossy white eggs. The incubation period is unknown and presumably by both sexes. Newly hatched young birds are blind and naked, with matt wrinkled skin, and pink chalky egg tooth. The lower mandible is longer than the upper. The skin turns grey after a few days. As soon as they are able to shuffle, they rapidly move backwards and forwards on the swollen papilla skin of the heel joint. The young are fed by both adults, provisioning rate fastest frommid-morning to early afternoon. Thereafter adults spend increasing proportion of time foraging for themselves. The nestling period is probably 30 days and most young fledge by early December, before the heavier rains. By December, both the adults and fledglings disperse away from their breeding sites, moving up to 1 000 km southwards. Although the Carmine Bee-eater is not threatened, many colonies along the Zambesi River were destroyed as a result of the construction of Kariba and Cahora Bassa Dams and colonies outside the National Parks in Zimbabwe are exploited as a food source. Although currently numerous, the Southern Carmine Bee-eater has its Achilles heel – there are relatively few breeding sites, which make the species extremely vulnerable. All breeding colonies should be recognised as sites of special conservation importance, and are deserving of rigorous protection. Some have already been deserted due to exploitation, while others have been disturbed by tourists and researchers. Colonies at sites in Botswana and Zimbabwe can be long lived, making protection a viable option to secure the status and survival of this species possible.

between neighbouring birds, which often engage in aerial pursuits. Whilst perched side by side, they utter a loud, clipped gro-gro-gro call. In flight their call is a short, bass, throaty klunk, chung, tunk or terk , sometimes a slightly rolled krunk ,often repeated six times. Their alarm call is a low, harsh chatter tirriktirriktirruk . They are locally common, with hundreds gathering in trees. They have a three-stage migration pattern, arriving on their breeding grounds in southern Africa from August to September. From December onwards, shortly after breeding, there is a wide scale dispersal of up to 650 km southwards into South Africa and Swaziland. From March to April, they migrate back to their non-breeding Equatorial savannas in Angola, Zambia, Malawi, southern Congo and western Tanzania. A few remain in the extreme northern parts of South Africa during our winter. These bee-eaters are aerial foragers, travelling far to exploit local eruptions of flying insects. They are readily attracted to bush fires, feeding on fleeing insects. They can be seen hawking insects in typical bee-eater fashion by following large herbivores or even vehicles, using them as beaters to flush their prey, such as grasshoppers, butterflies, cicadas and dragonflies. They also occasionally perch on large mammals, using them as mobile hunting perches, saving the bee-eater energy while inadvertently flushing suitable insect prey. They eat flying insects that are generally larger than those eaten by other bee-eaters. Their main prey consists of termite elates, cicadas, shield bugs, dragonflies and locusts. After catching their prey, it is carried back to a suitable perch and beaten, discharging the sting and venom of bees and wasps by rubbing the insect against the perch. The immobilising and de-venoming sequence takes only five to ten seconds before the insect is tossed into the mouth and swallowed. Whilst foraging over water they occasionally dive into the water, possibly in pursuit of fish or sub-surface insects. During foraging they regurgitate blackish pellets several times a day, smelling strongly of ammonia. These pellets comprise mostly of chitin and other indigestible insect remains. After arriving in the south from their non-breeding range further north in south-central Africa, around August, competition erupts for prime sites at the onset of breeding. Most breeding colonies are situated in high sandbanks of major tropical rivers – the Zambezi, Okavango, Kwando and Linyanti. In Botswana, where river banks are in short supply, they resort to burrowing in flat sandy soil, using nearby trees as perches. Their courtship rituals add to the organised chaos as birds renew pair bonds by courtship feeding. Southern Carmine Bee-eaters are apparently monogamous. They breed in large dense colonies with up to 1 000 nests per site and typically use the same site for many years. Their nests are burrows, excavated by both sexes.

Vultures have a helping hand with VULPRO

Simon Gear

Willie Froneman Birding Expert & Enthuisiast willie.froneman@gmail.com

White-backed Vultures

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63 | African Wildlife & Environment | 65 (2017)