The Southern Yellow-Billed Hornbill is found throughout southern Africa including south-west Angola, Namibia, Botswana, Zimbabwe, southern Zambia, southern Malawi, western Mozambique and northern South Africa.
It is a very common bird, and easy to recognise. They measure around 40cm from head to tail. They have a combination of pied white-spotted plumage (set with black). The most obvious giveaway of species is the long yellow bill. The males can weigh between 153-242g, and have a broad bill with a low casque that extends from ridge to tip. The female is smaller, weighing between 138-211g, and they have a smaller bill and shorter casque. The juvenile is very similar to the adults except they have a shorter, dull-yellow bill with brown spots. They are also known as “flying-bananas” due to their bills.
The Southern Yellow-billed Hornbill has an IUCN Red List Status of Least Concern, however, their numbers are decreasing, but their total population numbers are unknown.
The preferred habitat of yellow-billed hornbills is savanna and open woodlands, which includes being along rivers and they also like grasslands with scattered trees. In the west, they are also known to live in arid semi-desert and thorn-bush country.
They feed mostly on the ground, or in low bushes where they can be found walking or running to catch small prey. They are not known to do too much digging in the ground, but they will search the ground or among leaf litter, and they will search branches for small prey to pick off with their strong bills. They mostly prefer to eat small invertebrates, such as ant and termites, which is the most easily found prey in the dry season. However, when available, they will eat caterpillars, grasshoppers, beetles, centipedes and scorpions. They do take some vertebrate prey such as bird eggs and nestlings, and rodents when they can find them. They make also be found eating fruits and seeds when there is an abundance.
Southern yellow-billed hornbills are usually found in resident pairs or small family flocks, where they will stay in their home range all year. They are territorial and also return after feeding for the day.
As with all but 2 species of hornbill, the yellow-billed hornbill does use a nest cavity for breeding. The breeding season for this species of hornbill usually starts after the first summer rains in September to March. The nest is a natural cavity found in trees, usually from 0.8-12.2 metres up. They do compete with other hole-nesting birds using cavities, however they do seem to tolerate other Tockus species such as the Red-billed or African Grey, who may co-exist and nest nearby, occasionally in the same tree.
Yellow-billed hornbills are monogamous and the pair will start bonding about a month before they are ready to lay eggs. The courtship display includes calling, wing spreading, bowing heads and exchanging food. The nest is prepared with the entrance starting to be sealed and lining the internal nest floor with grass and leaves. The female enters the cavity after mating and finished sealing the entrance using mainly her own droppings, leaving it with a 5mm wide crack. The female will then take about 4-5 days to lay eggs, in which she could lay a clutch of between 2-6 eggs with intervals of 1-4 days. They incubation period for southern yellow-billed hornbill eggs is 24 days.
The female will moult all of her flight feathers during confinement. The bond between the mating pair has to be incredibly strong as the female is relying on the male to bring food as she cannot leave the nest. The male will feed the female, and then later feed the chicks when they hatch, bringing single food items to the nest at a time. The male will visit the nest around 3 times an hour at the beginning, which sharply increases when the eggs start to hatch, and peaks at 11 visits per hour when the chicks are 10-20 days old.
The eggs hatch in the order that they’re laid, which can last over a period of 9 days. The female will pass the food from the male to the chicks until they are about 10 days old, where they are then able to reach up and grab food directly from the male themselves.
The female is responsible for the house-keeping of the nest until the chicks are about 10-15 days old where they are then big enough to turn around and eject their droppings directly out of the nest entrance. The female will clean out the nest by removing soiled leaves that are on the nest floor until the chicks are big enough.
The female will emerge from the nest when the chicks are around 19-27 days old to help the male with the feeding. The chicks will re-seal the nest unaided from the inside. The chicks will then fledge the nest after 42-47 days, but they won’t all go at once, the younger chicks will stay in the nest and re-seal the entrance after the older ones have left. The whole nesting cycle lasts around 70-76 days.
The juveniles are very weak fliers immediately after leaving the nest and so they will hang around the nesting tree, and still get fed by the parents until they are strong enough to fly out and feed themselves. They gradually learn how to forage for themselves, but still get food from the parents up to around 6 weeks after leaving the nest.
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