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Quick Facts

They are the world’s largest cooperatively breeding birds, standing approximately one meter tall and weighing between 3.5 and 4.5 kilograms. These social birds typically form groups of three to five individuals, though group sizes can reach up to twelve.

Sex & Composition

Groups are led by an alpha pair, and supported by several ‘helpers’. These helpers are primarily male offspring from previous broods, along with occasional dispersing birds. Notably, non-alpha female birds are rarely tolerated and are often chased away at a young age. The “helpers” contribute towards various group behaviours including foraging, predator vigilance, territory defence, and reproduction.

The sex of the birds can be distinguished by looking at their facial colouration. Males have entirely red throats, while females have a patch of violet blue just below the bill. Younger birds can also be identified by a greyish-yellow throat, which they have for up to two years before slowly transitioning to the more mature red coloration. This transition process takes up to six years, so birds only display full adult coloration at around eight years of age.

Lifespan & Territories

Ground Hornbills are truly remarkable birds, renowned for their impressive longevity, with lifespans reaching up to 50-60 years in the wild. Throughout their lives, they occupy large home-ranges, ranging from 80 – 250 square kilometres, and are advertised through their iconic booming vocalisations, heard at dawn and dusk. These calls serve not only as a means of communication but also to establish their territory boundaries and strengthen group bonds. When it comes to group defence, they are prepared to implement physical tactics if the situation demands.

Diet

True to their name, Ground-Hornbills predominantly lead a terrestrial lifestyle. They spend their days strolling through savannah landscapes, foraging for a diverse array of prey—essentially anything they can overpower. Their diet mainly consists of invertebrates, but they are also known to hunt larger prey, such as snakes, lizards, small mammals, and birds. Equipped with a large, strong bill, these birds can easily catch and secure sizeable prey. Their long legs and toes enable them to navigate their environment swiftly and efficiently. While they are mostly ground-dwelling creatures, they are still very capable flyers and will roost, seek shade, and perform their territorial calls from the safety of trees.

Ground hornbill with a grass snake in its mouth.

Breeding occurs at the onset of the summer rains when there is greater food abundance. They nest in spacious cavities located high in large trees, rock faces, or earth banks.

Unlike other Hornbill species, the female Southern Ground-Hornbill does not seal herself inside the nest or undergo a moulting process during this time. Instead, she remains in the nest for most of the incubation and brooding period, emerging daily to join the rest of the group in performing territorial calls.

The female typically lays two eggs in a clutch. These eggs are laid three to five days apart and are incubated for approximately 40 days. Due to the staggered laying times, the chicks hatch at different intervals, resulting in the older chick outcompeting its younger sibling. Unfortunately, the second-hatched chick, being smaller and younger, succumbs to dehydration within a few days. This second egg serves as an insurance policy; if the first chick does not survive or if the first-laid egg fails, the group will have an opportunity to successfully raise the second hatched chick. Raising two chicks simultaneously has never been recorded in this species. The surviving Southern Ground-Hornbill chick remains in the nest for around 80 to 90 days, during which it is nurtured and fed by the entire group. Upon fledging, the chick is nearly fully developed, weighing between three and four kilograms. However, its beak remains significantly smaller than that of adult birds and will continue to grow as the young bird matures.

Southern Ground-Hornbills, are only found in Africa and predominantly inhabit regions south of the equator, with a small overlap in range with Northern Ground-Hornbills (Bucorvus abyssinicus) in parts of Uganda and Kenya.

They can be found across various countries, including South Africa, Namibia, Eswatini, Botswana, Zimbabwe, Zambia, Mozambique, Malawi, Angola, the Democratic Republic of Congo (DRC), Rwanda, Burundi, Kenya, Uganda, and Tanzania These birds prefer habitats such as savanna, grassland, and open woodlands, where a mix of open areas for foraging and trees for shade and nesting sites.

Unfortunately, Southern Ground-Hornbills have faced significant declines over the past century, with a two-thirds reduction in their population and range. As a result, they are classified as Vulnerable on a global scale and are considered Endangered in South Africa, Namibia, and Eswatini. In South Africa, most of the remaining population can be found in protected areas like Kruger National Park (KNP), Associated Private Nature Reserves (APNR), as well as conservation and farming regions in KwaZulu-Natal and rural areas of the Eastern Cape. Conservation efforts are vital for ensuring the survival of these birds and safeguarding their natural habitats

Habitat Loss

Southern Ground-Hornbills face significant threats due to habitat loss and a decline in available nest sites. In some countries, they have experienced a staggering 70% to 90% reduction in their original range and are now primarily found in large, protected areas. This decline is attributed to factors such as human expansion, extensive farming, bush encroachment, overgrazing, and climate change. Additionally, the scarcity of large trees limits the birds' ability to find suitable nesting sites, further jeopardizing their populations.

Persecution

The territorial behaviours of Southern Ground-Hornbills often lead to conflict with humans. The birds often perceive their reflection in windows, mirrors, or other reflective surfaces as an intruder, prompting them to attack and peck at the glass. The behaviour can result in significant damage to property and may lead to further persecution of the birds.Occasionally, Southern Ground-Hornbills are also targeted due to cultural beliefs where, in some cultures, they are regarded as ‘rain birds’ and are thought to possess the ability to summon rain, especially in times of drought.

Poisoning

Occasionally, Southern Ground-Hornbills will scavenge at carcasses, which puts them at risk of poisoning. If a carcass has been laced with poison, consuming the meat can have devastating and fatal effects not only on the Ground-Hornbills but also on other scavengers that feed on the contaminated remains. Additionally, they are at risk of lead poisoning when feeding on animals shot with lead bullets, which poses another serious threat to their survival.

Climate Change

Climate change is amplifying challenges for bird species in Southern Africa, as rising temperatures and extended heatwaves worsen the already harsh climate. The excessive heat can cause higher mortality rates, interrupt breeding cycles, and reduce food availability. Ground hornbills face growing threats from increasing temperatures, posing serious risks to their survival. Our research seeks to examine these environmental threats to guide successful conservation efforts and improve the protection of this at-risk species.