Southern Ground Hornbill

(Bucorvus Leadbeateri) [ WRITER: Sean Hind (Safaris I Can See) ] [ PHOTO: Sean Hind / National Geographics ]

It is 4:45am in the morning, I am in the middle of Hwange National Park, there is a booming sound in the distance, is it a lion? No it’s the deep booming sound of a pair of southern ground hornbills announcing the start of a new day. These birds are very territorial and the calling is to advertise their territory and is done mostly at dawn or early morning when the air is still cool and allows for the sound to travel further, sometimes as far as three kilometres.

It is always a great sight to come across a group of ground hornbills slowly moving through the bush foraging. These large black birds are often found in groups of three to five birds, but sometimes up to nine birds or more. They are often referred to as turkey buzzards because of the way they look and walk around but it has no close genetic affiliations to either, in fact the genus Bucorvus literally means huge crow.

The ground hornbill is slightly different to the other smaller more typical hornbills in that it has 15 vertebra and not 14 and this could be an adaptation to the fact that the ground hornbill spends about seventy percent of the day on the ground feeding. When moving through the bush, group members sometimes inadvertently flush prey towards one another. They will pretty much feed on anything they came across, from tortoises to dung beetles and snakes to frogs, pretty much anything goes. If an individual bird comes across a large prey species he will give a little bark and the others in the group will come and help out. The southern ground hornbill has a long life span, possibly living up to forty years. It isnt possible to age the ground hornbills until they reach maturity. It takes anywhere between four to six years to reach maturity and when this happens their facial skin will be fully red, the female has a blue patch on the bare skin under the throat. So for the first year the facial skin starts off as grey-brown, turning yellow by the end of the year, by two years the facial skin is flecked red and at three years it is orange. This makes it a very long breeding cycle. They are monogamous, cooperative breeders. You will have the dominant breeding pair and the rest of the birds in the group will be helpers. The nest is usually built in a cavity of a tree or sometimes in a rock face, the cavity is not sealed, like with other hornbills. The female bird normally lays one to two eggs which hatch asynchronously, this means if there are two eggs laid, then normally only the first chick to hatch will survive as the second born cannot compete with the older chick for food and usually dies of starvation within the first week. The smaller clutch though means more dedicated parental care, which lowers mortality. Fledglings remain with the parental group until they reach maturity. Unfortunately, the southern ground hornbill is listed as vulnerable throughout its sub-Saharan range (Birdlife International 2012), the main threats in Zimbabwe to this bird is habitat destruction, the large trees that the bird needs for nesting are reducing rapidly due to deforestation, which is because of the growing human population. The other causes of decline are secondary poisoning when they scavenge off carcasses laced with poison for pest control, and they also get persecuted for breaking house and car windows when hammering at their own reflections in territorial aggression. There is little known about the population in many of the areas where the ground hornbill exists in sub-Saharan Africa but it is reported that the numbers are in decline.

Birdlife Zimbabwe is currently running a project to try and work out what the population of southern ground hornbill is in Zimbabwe. Please have a look at their website for more information on this project. www.birdlifezimbabwe.org Happy Birding