Southern Ground-Hornbill conservation
Southern Ground-Hornbills Bucorvus leadbeateri are large, group-living birds that require extensive territories and relatively undisturbed areas with large trees for breeding and roosting. With high rates of habitat loss during the past century, 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 investigated their habitat use, breeding success, and dispersal. Now we are studying their social behaviour, specifically how group members contribute to territory defence and reproduction, and whether larger groups are more resilient to global change.
The long-term project has provided nest boxes to 20 hornbill groups throughout the Associated Private Nature Reserves, adjacent to the Kruger National Park. These groups together make 12-15 breeding attempts each year, providing an ideal platform to study this elusive species. This project also is closely linked to the Mabula Ground-Hornbill Project, providing second-hatched chicks (which invariably die of starvation in the wild) to be captive-reared and later released as founder groups in new areas.
PhD student Kyle-Mark Middleton, supervised by Rita Covas, Claire Spottiswoode and Fanny Rybak, is focusing on understanding the hornbill’s social structure and individual contributions to breeding success and territory defence. Kyle obtained many hours of recordings of the different groups’ dawn chorus and his analyses have shown differences between the sexes, and among individuals and groups. Play-back experiments are being conducted to determine if the birds also perceive these vocalisations as different.
Kyle has also obtained footage from camera traps installed at the nests to obtain insights into the private lives of ground-hornbills. Initial results reveal disproportionate contributions to chick feeding among individuals, as well as temperature-linked variation in provisioning rates. Using the long-term breeding data, Kyle is also investigating which environmental factors affect breeding performance and how their cooperative behaviour might help to buffer harsh environmental conditions.
MSc student Carrie Hickman, supervised by Rita and Susan Cunningham, is investigating whether high ambient and nest temperatures impact hornbill nestlings by measuring nestling growth, fledging size and condition, and telomere length. Piecewise modelling will be used to investigate whether any impacts result from a decrease in the frequency or quality of provisioning or from direct effects of temperatures inside the nest. Initial analysis of camera trap footage suggests that provisioning rates decrease at high ambient temperatures. iButtons have been installed inside nests to obtain hourly temperature recordings.
Activities in 2020
- Carrie began her master’s degree on the effects of high temperatures on nestling growth rates.
- Kyle’s analyses show that different groups have unique ‘signatures’, and that males produce lower frequency calls than females. At least six different vocalisations have been identified: chorus, contact, excitement, alarm, begging and feeding calls. A distress call is also suspected to occur.
- Playback experiments were conducted to investigate whether groups can recognise neighbouring groups from stranger groups through vocalisations.
- Kyle completed his analyses of long-term breeding success in relation to environmental variables and group structure, which revealed an effect of rainfall, temperature and breeding group composition.
- Before the 2020/21 breeding season began, camera traps were placed in camouflaged boxes at 13 nests to record birds provisioning food, and iButtons were installed inside each nest.
- Distinctive facial features can be used to recognise individuals and thus assess how much different birds contribute to nestling feeding. Initial analyses suggest that adult males feed the incubating female and chick more than sub- adult male helpers. Juveniles also occasionally contribute, although to a much lesser extent.
- Non-invasive genetic sample collection from known individuals is continuing through shed feathers to determine relatedness between individuals and how this influences investment in cooperative behaviour.
- Blood sampling of nestlings was started to determine the effects of temperature on nestling growth rates and allow chicks to be sexed.
- Carrie and Kyle attended the Southern Ground-Hornbill reintroduction workshop hosted by BirdLife South Africa and the Mabula Ground-Hornbill Project.
- The project created a new website, providing general information on the research and conservation conducted within the area.
- Five presentations were made to create awareness and four articles appeared in the Klaserie Chronicle, which is distributed to the greater Hoedspruit community. Two online articles were published on the Timbavati blog and on the Africa Geographic platform.
- Kyle and Carrie appeared on a 15-minute insert on the television program ‘50/50’ where they described their research and how the project contributes towards ground-hornbill conservation.
- Kyle won the prize for best presentation from a developing country at the African Bioacoustics Conference.
- The 2019/20 breeding season saw eight chicks fledge from 12 nests. Egg candling was used to estimate hatch dates for harvesting and methods are being developed to sex birds whilst still in the egg.
- Ongoing repairs to and replacement of artificial nest boxes ensured that ground-hornbills can continue to thrive in the study area, which has few natural nest cavities. Five newly designed nests were installed, equipped with iButtons to determine if they provide ideal conditions for breeding.
- A new group of only two ground-hornbills began to breed in a new nest. This shows that breeding can occur without the assistance of helpers.
- Footage was obtained of leopards predating ground-hornbill nestlings.
- New funding collaborations were established with Wild in Africa, as well as Wild Wonderful World, and a new project vehicle was acquired, allowing the project to continue into the foreseeable future.
Impact of the project
This project continues to contribute 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.
DSI-NRF CoE grant; The Foundation for Science and Technology FCT, Portugal; Associated Private Nature Reserves; National Geographic Society; Mary Oppenheimer & Daughters Foundation, Wild in Africa, Wild Wonderful World.
Research team 2020
Dr Rita Covas (FIAO, UCT and CIBIO, U. Porto)
Prof. Claire Spottiswoode (FIAO, UCT / U. Cambridge)
Dr Fanny Rybak (U. Paris-Sud, France)
Dr Rob Little (FIAO, UCT)
Students: Kyle-Mark Middleton (PhD, UCT); Carrie Hickman (MSc, UCT).