Southern Ground-Hornbills Bucorvus leadbeateri are large, group-living birds that require extensive territories with large trees for breeding and roosting. Habitat loss has led to a two-thirds reduction in their range in South Africa during the past century. A long-term study has investigated their habitat use, breeding success, and dispersal. Now we are studying how group members contribute to territory defence and reproduction, and whether larger groups are more resilient to environmental change. We are also investigating how high temperatures influence breeding success.

The long-term project has provided nest boxes to 24 ground-hornbill groups in the Associated Private Nature Reserves (APNR), adjacent to Kruger Park. Together, these groups make 12-15 breeding attempts each year. This area is now a national population stronghold for the species and this successful population is now dispersing outside of the APNR and is re-populating the surrounding area. The project also provides second-hatched chicks (which invariably die of starvation in the wild) to the Mabula Ground-Hornbill Project (MGHP) for captive-rearing and later release. PhD student Kyle-Mark Middleton, supervised by Rita Covas, Claire Spottiswoode and Fanny Rybak, studied the hornbill’s social structure and individual contributions to breeding and territory defence. He compared different groups’ dawn choruses and used play-back experiments to determine if the birds recognise different groups. He also used camera traps at the nests to obtain insights into the hornbills’ private lives, and analysed long-term data to investigate the environmental and social factors affecting breeding performance.

PhD student Carrie Hickman, supervised by Rita Covas and Susan Cunningham, continued her work investigating whether high air and nest temperatures impact hornbill nestlings by measuring nestling growth, fledging size and telomere length (a measure of physiological condition). She is also recording the hornbill’s behavioural responses to high temperatures. iButtons (devices used for data logging) have been installed inside nests to obtain hourly temperature recordings and camera traps are used to record provisioning. The results from these analyses will assist in designing better nest boxes for the species and provide information on locations where the birds will have the best chance to persist, where microsites are more favourable and temperature increases are slower .

Activities in 2023

  • Kyle-Mark Middleton graduated in March 2023 with his thesis “Individual contributions to group behaviour in the cooperatively breeding southern ground-hornbill”.
  • Kyle now works for Mabula Ground-Hornbill Project as senior coordinator implementing conservation actions throughout the lowveld, but he remains as an important part of the ground-hornbill team and assists with field work.
  • Carrie Hickman successfully carried out another field season for her PhD, where nine ground-hornbill nestlings fledged in February and March 2023, contributing to her dataset on nestling growth and physiology.
  • Carrie completed a winter field survey in July, looking at shade availability for ground-hornbills. Towards the end of the year, she continued with fieldwork for another breeding season which included weighing and measuring nestlings at specific ages to obtain growth rates.
  • Kyle and Carrie attended and presented at the 8th International Hornbill Conference in Bangkok, Thailand. They visited Khao Sok National Park, where they were lucky to see the Great Hornbill and Oriental Pied Hornbill as well as many other incredible bird species.
  • In August, Carrie travelled to Cape Town to attend and present at both the Fitz AGM and the Hot Birds Research Project biennial conference.
  • Kyle continued to assist on the project, helping with ongoing repairs and replacement of artificial nest boxes. This ensures that ground-hornbills can continue to thrive in the study area, which has few natural nest cavities.
  • In October, Carrie and Kyle participated in an episode of the podcast, “Campfire Conversations” with Brett Horley of BHS Safari Company where they discussed their work conserving and researching ground-hornbills.
  • In December, five second-hatched chicks were removed from nests in the APNR and transported to the MGHP’s rearing facility at Loskop Dam. This year a volunteer pilot from the Bateleurs (an environmental airforce who fly for conservation projects), flew three of these chicks to the facility. This decreased the transport time to just one hour compared to 5 hours, reducing the stress on both the tiny chicks and team involved in the process. In December, Katleho, an intern from Mabula Ground-Hornbill project, and Roos, an MSc student from the Netherlands joined the project in the field to gain some fieldwork experience .


  • Kyle graduated with his PhD in March 2023.
  • The 2022/23 breeding season saw nine chicks fledge out of 15 breeding attempts and the 2023/24 breeding season started well with 14 breeding attempts.
  • Five chicks were harvested for the reintroduction programme, with some flown to the rearing facility by the Bateleuers.
  • Three new groups have been indentified in the APNR, thanks to camera traps placed at nests.
  • An incubating female was killed inside the nest by an intruding pair of ground-hornbills. Footage of this was captured on a camera trap which then showed the remaining group members accepting the intruding pair into their group over the weeks that followed.
  • Six new nests were placed outside the study site to encourage natural dispersal.
  • Three new nests were installed on the edges of the reserve within the study site, where ground-hornbills have been seen, but natural nests have not been found.
  • A new active natural nest was discovered within the APNR .

Impact of the project
This project continues to generate fundamental knowledge about the species, the factors affecting reproduction, their social structure and their physiology. It also contributes to the population growth of Southern Ground-Hornbills in the APNR and has demonstrated the efficacy of artificial nests as a conservation tool in areas where natural cavities are scarce. The surrounding areas are now beginning to benefit from the project, with new groups occurring in areas previously lacking ground-hornbills. The project contributes to the national Southern Ground-Hornbill Species Action Plan and the Southern Ground-Hornbill Reintroduction Plan.

Key co-supporters
The Foundation for Science and Technology FCT, Portugal; Associated Private Nature Reserves; National Geographic Society; The Rufford Foundation; Mary Oppenheimer & Daughters Foundation; John Solomon; Timothy Hancock Charitable Trust; Wild Wonderful World; Bateleurs.

Research team 2023
Dr Rita Covas (FIAO, UCT / CIBIO, U. Porto)
A/Prof. Susie Cunningham (FIAO, UCT)
Prof. Claire Spottiswoode (FIAO, UCT / U. Cambridge)
Dr Fanny Rybak (U. Paris-Sud, France)
Dr Kyle-Mark Middleton (FIAO, UCT / Mabula Ground- Hornbill Project)

Student:: Carrie Hickman (PhD, UCT).