I’m looking forward to entering the peak of the rainy season, which brings a very special sound to the African bush. Shortly after the sun rises, the air will often be filled with deep booming notes. So deep and resonating that it can sometimes take a trained ear to tell it apart from the roar of a very distant lion.
When it comes to waking up and setting out into the bush early, I find that always gain far more than I initially seek. This particular morning was no exception. It was still and peaceful. We decided to stop in an open clearing where herds of impala surrounded us, with elephants feeding in the distance. With the vehicle’s engine off, we tee’d ourselves up perfectly to listen to the sounds of our surroundings. Especially, any animal alarm calls or perhaps even the rasping of the leopard we were searching for. We sat for a while enjoying the scene. Then suddenly, we heard faint booming notes.
The booming sound we heard was the duet between a male and female Southern Ground Hornbill, advertising their territory. The last thing my guests were thinking was that this sound was being made by a bird. My good friend and tracker Terrence, assured everyone that I had identified the sound correctly. On a quiet morning like this one, their call can be heard up to almost 2.5 miles away as it rumbles through the bush. With that being said, you’ve got a good chance of hearing them if they are in the area.
Southern Ground Hornbills have very large territories, and different family groups will proclaim their territories each morning. This ensures the surrounding groups will be aware of each other’s presence. In order for their call to be the most effective and travel large distances, I’ve seen them perform this booming call mostly from an elevated position. This is to avoid the sound being muffled out by trees or vegetation, helping it to have a further reach.
They create their booming call through the ability to inflate a sack-like chamber in their red wattle that covers their throat. The sound then reverberates through this sack, which enhances it. They also have a special chamber on their upper bill in order to amplify the sound. The male has a larger chamber, and this is why you will often hear the two different pitches in a morning duet, with the male’s being deeper in tone.
They are unmistakable in appearance, standing over a metre high when fully grown and weighing up to 5kg. They are the largest hornbill species in the world.
It was needless to say that later that day, we were caught in a torrential downpour accompanied by thunder rumbling in the distance. Whether or not they do actually bring the rain or because the rainy season coincides with their breeding season (which is when they are most vocal and territorial), will remain anyone’s guess. Whatever the belief is, these birds carry with them a great sense of veneration. Their call does stir some great imagery and emotion. It is for that reason that they are certainly right up there with my favourite birds found on the reserve.