The southern ground-hornbill (Bucorvus leadbeateri) is the largest of the hornbill species and occurs from Kenya and the Democratic Republic of Congo to Angola, Namibia and South Africa. The male Southern Ground Hornbill has a magnificent red wattle (throat pouch) compared to the dark blue wattle of the Northern Ground Hornbill (Bucorvus abyssinicus). When calling, these wattles are inflated, with the southern species' call being a "lion-like" sound which carries for quite a distance and is sometimes heard as a duet at dawn between pairs. These hornbills have one of the slowest reproductive rates in the bird kingdom, producing only one chick approximately every 9 years.