Conserving Verreaux's Eagles
Verreaux’s Eagle Aquila verreauxii has recently been upgraded to “Vulnerable” in South Africa due to decreases in range and abundance recorded by the Southern African Bird Atlas Project. Land use change, habitat loss and more recently, the development of the wind energy industry, all pose threats to this species. Initially, this project explored the ecology of Verreaux’s Eagles in natural and agriculturally transformed habitats. Generally regarded as a highly specialised raptor, habitat transformation was predicted to reduce availability of preferred prey species (Rock Hyrax Procavia capensis), resulting in reduced breeding productivity or increased foraging efforts. Contrary to this prediction, our research in the Cederberg and Sandveld regions of the Western Cape found that Verreaux’s Eagles are in fact diversifying their diet in agriculturally developed areas and their breeding productivity does not appear to be negatively impacted.
High-resolution GPS tracking technology proved to be important to understand the ranging behaviour of Verreaux’s Eagles in contrasting habitats. This technology is now being used to understand flight behaviour and the associated risk of wind turbine collisions. Like many other large soaring raptors, Verreaux’s Eagles are particularly prone to wind turbine collision risk. During 2015, at least five Verreaux’s Eagle fatalities were recorded at wind farms in South Africa. Although wind energy in Africa is still in its infancy in comparison to many other countries, the sector is developing at a rapid rate. The GPS data will be used to build habitat use models that explore how territory holding eagles use the landscape. In particular, we need to understand how factors such as distance from the nest, topographical features and collision risks influence their movements.
The aim is to incorporate these models within a user-friendly, web based interface for use by the wind energy industry to obtain a relative collision risk map of potential development areas, thereby ensuring that wind turbines can be placed in locations that will minimise risk to flying eagles.
Activities in 2016
- A collaboration was started with Andrew Jenkins of AVISENSE Consulting to GPS tag Verreaux’s Eagles at a wind farm development site in the Karoo. Six Verreaux’s Eagles were equipped with high-resolution GPS tags from the University of Amsterdam Bird Tracking System. These tags have already yielded huge amounts of high resolution tracking data, which will be used for the Environmental Impact Assessment and for our proposed collision risk model.
- Megan Murgatroyd presented her key PhD results at the Pan African Ornithological Congress in Dakar, Senegal.
- Megan presented her Post-doctoral research proposal at the Birds and Renewable Energy Forum hosted by BirdLife South Africa and the Endangered Wildlife Trust (EWT) at Kirstenbosch.
- Megan submitted and received her PhD entitled “Ecology of the Verreaux’s Eagle in natural and agriculturally transformed habitats” supervised by Les Underhill (ADU, UCT) and Arjun Amar.
- The first paper from Megan’s PhD research was published on the influence of agricultural transformation on the breeding performance of Verreaux's Eagles (Murgatroyd et al. 2016. Condor).
- Research on the diet of Verreaux’s Eagles was also published (Murgatroyd et al. 2016. J. Avian Biol.).
- Research using high resolution GPS tracking to investigate ranging behaviour and habitat preferences was published and is available open access. (Murgatroyd et al. 2016. PLoS ONE).
Impact of the project
This project has added to our understanding of the ecology and habitat requirements of Verreaux’s Eagles. The primary aim of the ongoing work is to contribute to reducing future injuries and mortalities of Verreaux’s Eagles via wind turbine collisions throughout their range. This will contribute to the long-term sustainability of wind development within Sub-Saharan Africa and minimise the impact on one of the most widespread and vulnerable eagle species on the continent.
ABAX Foundation; DST-NRF CoE grant.
Dr Arjun Amar (FIAO, UCT)
Prof. Les Underhill (ADU, UCT)
Dr Andrew Jenkins (ADU, UCT)
Student: Megan Murgatroyd (FIAO and ADU, UCT)