Southern Ground-Hornbills (Bucorvis leadbeateri) are large unique birds, endemic to Africa. Their distinctive black plumage, bright red facial skin and large beaks make them unmistakable in the African bushveld and differentiate them from the other Hornbill species found worldwide. The scientific name Bucorvis leadbeateri derives from the word Bucorvis meaning ‘large crow-like bird’ and leadbeateri from Benjamin Leadbeater, a Victorian naturalist from London who first described the specimen, Southern Ground-Hornbill.
They are the world’s largest cooperatively breeding birds, standing at around one meter tall and weighing around 3.5 – 4.5 kilograms. Groups usually consist of three to five individuals but can go up to 12 in a group. Within each of these groups, there is an alpha pair, which are followed by several “helpers” consisting of male offspring from previous years, as well as the occasional dispersal birds. Female birds other than the alpha female are seldom tolerated within groups and are often chased out at a young age. The “helpers” contribute towards a variety of 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 throats that are entirely red, while females have a patch of violet blue just below the bill. Younger birds can also be identified by a grey/yellow throat, which they have for up to two years, before slowly transitioning to the more mature red colouration. This transition process takes up to six years, and so birds, only display full adult colouration from about eight years old.
They are incredibly long-lived birds, reaching an age of up to 70 years, and they occupy large home-ranges, measuring from 80 – 250 square kilometres. These home-ranges are advertised through their iconic booming vocalisations, which are produced during the hours of dawn and dusk. These calls are not only a means of defence, but also as a way to further group bonding and cohesion. In the case of group defence, physical defence will be implemented if necessary.
As the name ‘Ground-Hornbill’ suggests, these birds live a largely terrestrial lifestyle. They spend most of the day walking through the grass, foraging and hunting a variety of prey species – generally anything they can overpower. Their diet consists mainly of invertebrates and includes larger prey items such as snakes, lizards, small mammals, and birds. Their large strong bill allows them to catch and hold onto large prey and their long legs and toes allow them to walk effectively and quickly. 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.
Southern Ground-Hornbills’ lifespans are extensive, but their breeding productivity is low, with each group fledging a maximum of one nestling per year.