Southern Ground-Hornbill conservation
Southern Ground-Hornbills Bucorvus leadbeateri are large, group-living birds which require extensive territories and relatively undisturbed areas with large trees for breeding and roosting. With high rates of habitat destruction during the past century, which has accelerated in recent decades, these requirements have become increasingly rare, leading to a two-thirds reduction in the Southern Ground-Hornbill’s range within South Africa. A long-term study at the Fitz, initiated in 2000, has been investigating their habitat use, reproductive success, and natal and breeding dispersal. Now we are building on this foundation to study the social behaviour in more detail, specifically how group members contribute to vital group functions such as territory defence and reproduction, and whether larger groups are more resilient when facing extreme climate events.
The current focus of the project, located in the Associated Private Nature Reserves (APNR) adjacent to the central Kruger National Park, is on better understanding the species’ social structure and individual contributions to breeding success and territory defence. The study provided nest boxes to 20 groups which collectively make 12-15 breeding attempts each year. PhD student Kyle-Mark Middleton, supervised by Dr Rita Covas, Prof. Claire Spottiswoode and Dr Fanny Rybak, has obtained many hours of recordings of the different groups’ dawn chorus and in 2019 travelled to Paris to analyse the vocalisations with Fanny Rybak. These analyses have shown differences between the sexes, and among the vocalisations of different individuals. Play-back experiments were planned to assess if the birds also perceive these vocalisations as different. However, due to late rains and high temperatures in the 2018/19 breeding season, very few groups attempted to breed and the play-back experiment was postponed until the 2019/20 breeding season.
Kyle has also obtained footage from camera traps installed at the nests which has allowed for the private lives of ground-hornbills to be investigated and analysed. Initial results reveal interesting disproportionate contributions from individuals in the groups.
This project is closely linked to the Mabula Ground-Hornbill Project. We provide the second-hatched chicks from our population, which invariably die of starvation in the wild, to be captive-reared and later released as founder groups in new areas.
Activities in 2019
- Kyle Middleton upgraded from a MSc to PhD. He is researching the cooperative breeding behaviour and vocalisations of Southern Ground-Hornbills within the APNR.
- Kyle joined Fanny Rybak at U. Paris-Sud, to continue the analyses of group and individual vocalisations. The results suggest that different territorial groups have unique ‘signatures’, and that male birds produce vocalisations at a lower frequency than that of females.
- The repertoire of ground-hornbills consists of six different vocalisations used for different situations: chorus, contact, excitement, alarm, begging and feeding calls. A distress call is also suspected to occur, but this could not be recorded.
- The first playback experiments were conducted to investigate whether groups are able to recognise neighbouring groups from stranger groups through vocalisations.
- Kyle travelled to Portugal to join Rita Covas at CIBIO (U. Porto) to begin the analysis of long-term breeding success in relation to environmental variables and group structure.
- Before the breeding season began, camera traps were placed in camouflaged boxes at 12 nests, to record birds provisioning food at the nest.
- Initial camera trap analysis shows that adult males contribute more to the feeding of the incubating female and chick than sub-adult male helpers. It also appears that juvenile birds are unaware of the provisioning process.
- Continued efforts to identify individuals by non-invasive techniques using camera traps to photograph the birds’ face yielded positive results, suggesting that distinctive facial features are an effective method of identification. This is being used to study the individual contributions to nestling feeding.
- Genetic sample collection for known individuals is continuing through non-invasive methods from shed feathers. This is to determine relatedness between individuals and how this influences investment in cooperative behaviour.
- Three of Kate Carstens’ PhD chapters where published as peer-reviewed papers in Bird Conservation International, Journal of Ornithology and Ostrich.
- Rob Little represents the Fitz on the national Southern Ground-Hornbill Working Group and is Vice Chairman of the Mabula Ground-Hornbill Project management board.
- During 2019, the project gave ten presentations to the general public (including one local school) to create awareness and published four articles in the magazine Klaserie Chronicle which is distributed to surrounding private reserves and the greater Hoedspruit community.
- An article was published in Kruger Magazine presenting the project’s history and aims. Some reserves surrounding the APNR are showing increased attention towards the species and their conservation.
- A generous donation from the Mary Oppenheimer and Daughters Foundation, supplemented by some of the homeowners in the APNR, allowed the project to purchase a new vehicle. This will allow the project to continue for the foreseeable future.
- Kyle received funding for his research from the National Geographic Society.
- The Mabula Ground-Hornbill Project held an avian first aid course which Kyle attended to aid field conservation.
- A group of ground-hornbills was confirmed to have two females in the group, both of which were contributing towards the feeding of the offspring, something never seen before.
- An injured ground-hornbill was found inside a nest. This bird was taken to Onderstepoort Veterinary Hospital where it was rehabilitated and then released back into the APNR.
- The 2018/19 breeding season saw only five active nests, and all five chicks successfully fledged.
- Egg candling was used to provide an accurate estimate of the hatch date for harvesting and methods are being developed to sex birds whilst still in the egg.
- Ongoing repairs to and replacement of artificial nest boxes ensure that ground-hornbills can continue to thrive in an area which has a paucity of natural nest cavities. The new nest designs were installed and one of them was used immediately.
Impact of the project
This project has contributed significantly to the population growth of Southern Ground-Hornbills in the APNR as a result of the installation of artificial nests and has demonstrated the efficacy of these nest boxes as a conservation tool, particularly in areas that have a shortage of large trees with natural cavities. These results contributed to the national Southern Ground-Hornbill Species Action Plan and to the Southern Ground-Hornbill Reintroduction Plan and assist with their implementation.
DST-NRF CoE grant; The Foundation for Science and Technology FCT, Portugal; Associated Private Nature Reserves; National Geographic Society; Mary Oppenheimer & Daughters Foundation.
Research team 2019
Dr Rita Covas (FIAO, UCT / CIBIO, U. Porto)
Prof. Claire Spottiswoode (FIAO, UCT / U. Cambridge)
Dr Fanny Rybak (U. Paris-Sud, France)
Dr Rob Little (FIAO, UCT)
Student: Kyle-Mark Middleton (PhD, UCT)
Research assistant: Carrie Hickman.