The Mabula Ground Hornbill Project (MGHP) was initiated in 1999 and it is the mission of the project to halt the decline in numbers of the Southern Ground-hornbill (Bucorvus leadbeateri, hereafter ground-hornbill). This is achieved through a multi-faceted approach of education and awareness, threat mitigation, provision of artificial nest sites, and improving the population size in the wild through hand-rearing and reintroduction. Throughout its range, the ground-hornbill is in decline due to a number of threats, almost all caused by humans. These include habitat loss, secondary poisoning, loss of nest sites; persecution for breaking windows and trapping. The species is considered Endangered in South Africa and Namibia, and in decline in most of its sub-Saharan range. An estimated 2000 individuals remain in the wild, with just a third of this population (200-250 groups) in protected areas such as the Greater Kruger National Park. The rest of the population is in private, communal or state-owned land in Limpopo, Mpumalanga, Eastern Cape and KwaZulu-Natal.
In addition to being the largest cooperatively breeding bird species in the world, ground-hornbills are long-lived; reaching an age of 60 – 70 years. Sexual maturity is reached at eight years old at the earliest. In the wild, breeding is concurrent with the rainy season. Two eggs are usually laid about 5 days apart, and hatch after 37- 42 days of incubation. Sometimes one, and rarely three eggs are laid but the species never raises more than one chick per breeding attempt. One, usually the second-hatched chick, always dies due to dehydration. They also do not attempt to breed every year, meaning they simply cannot breed fast enough for their population to remains table in the face of ongoing human-induced treats.
Part of the conservation solution is a captive breeding population, held by a number of partner institutions, including the Joburg Zoo. The collaboration between MGHP and Joburg Zoo started in 2003. We have had highs and lows with this difficult species. Hand-rearing is extremely intensive and requires total dedication, long hours and experienced staff but we have successfully reared more than ten birds, one of which has been reintroduced into the wild and the others are cared for by other instituions that form part of the project: The National Zoo, Zaagkuilsdrift Bird Sanctuary, Loskop Dam Nature Reserve and Montecasino Bird Gardens.
Currently the Johannesburg Zoo and Zoo farm cares for 6 birds, two housed behind the scenes and two on display to the public and two at the Zoo farm in Parys. One male, Ntwanana, is already 23 years old. At present we have not had any breeding success but remain optimistic that, with time, we will become successful breeders. One of our birds is a rescue bird brought to us with deformed feet and organ damage and due to the diligence and dedication of the zoo keepers and veterinary teams, it is today well on its way to becoming a valuable contributor to the population.
Currently, a world-class rearing centre, that will be called the Baobab, is currently under construction at Loskop Dam Nature Reserve. This centre will ensure that all ground-hornbill hand-rearing activities are centralized in one location, guaranteeing homogeneity in the hand-rearing and socializing process and in turn, minimizing the production of chicks that are unsuitable for release in the wild. Currently there are three successful release sites; Mabula Private Game Reserve, Loskop Dam Nature Reserve and Thaba Tholo Game Farm. These sites are used as ‘bush schools’ where experienced adult males teach the younger birds the vital survival skills they need in the wild. Once the younger males have gained experience, they will then be transferred to other release sites where they will be the alphas of subsequent groups.
There are multiple stakeholder meetings every year to plan, implement and refine conservation action for ground-hornbills. This group has produced a Single Species Recovery Plan, a Population and Habitat Viability Analysis and annually produces a PAAZA studbook and husbandry manual and our next big step is undertaking a Biodiversity Management Plan for the species that will be gazette by government, securing national support for the conservation of this iconic species.
References
- Poonswad P, Kemp A.C Strange M. 2013. Hornbills of the World: A Photographic Guide. Draco Publishing, Singapore.
- Kemp, A.C. and Begg, S.G. 1995. Nest sites of the Southern Ground Hornbill Bucorvus leadbeateri in the Kruger National Park, South Africa, and conservation implications. Ostrich. 67: 9-14.
- Kemp, A.C. 2005. Southern ground hornbill Bucorvus leadbeateri. In: Roberts – Birds of Southern Africa, (eds) P.A.R. Hockey, W.R.J. Dean & P.G. Ryan, 7th edn, pp. 158–159. The Trustees of the John Voelcker Bird Book Fund, Cape Town.
