Verreaux’s Eagle

Development of wind farms, especially in mountainous areas, poses a threat to Verreaux’s Eagles. There is significant overlap between the distribution of this species and wind energy development. To date there have been more than 30 collisions of Verreaux’s Eagles with wind turbines, and this threat is expected to continue to increase as the wind industry grows. From operational monitoring in South Africa, 0.01 Verreaux’s Eagle carcasses have been recorded per turbine per year. This does not account for searcher efficiency or scavenger removal. The adjusted fatality rate at one Wind Energy Facility was 2.2 times higher than the observed fatality rate (Ralston-Paton In press). Thus, based on the current installed wind energy capacity, of 3490 MW, or 1421 turbines (Ralston-Paton In press), the annual fatality rate from wind energy alone is likely to currently be in the region of 14.2 – 31.3 Verreaux’s Eagles per year. Given projected growth of the wind energy industry, if the target of 17700 MW of wind energy installed by 2030 (Integrated Resource Plan, 2019), and assuming higher MW per turbine (4MW/turbine) is also achieved, then we can extrapolate an additional 4425 wind turbines in the region and 58.5 – 128.6 Verreaux’s Eagle fatalities per year from wind energy alone in 2030. Based on the observed age distribution of fatalities already recorded, most of these (81%) are likely to be adults.

In addition, there has been an increase in persecution events related to development, in which eagles may have been killed and/or their nests have been intentionally destroyed (by fire, removed from the cliff), so that they do not appear in the Environmental Impact Assessment and thus hinder development. There is a strong need for a “Code of Conduct” around the establishment of new developments, which make it clear that any nests will be buffered from development regardless of their current status – this is primarily due to the fact that even currently vacant territories are likely to become occupied during the operational lifespan (>20 years) of a development.

Between 1996-2019 there were at least 22 collision mortalities and 69 electrocutions on high voltage powerlines. Additional electrocutions are also known to have occurred on poorly insulated 33kV powerlines associated with wind turbines.

Pressure from stock farmers also presents a major threat to Verreaux’s Eagles within the region (Davies 1994). Direct persecution by farmers is usually in retaliation to these eagles catching domestic livestock (Anderson 2000). Ironically, the beneficial role that a pair of Verreaux’s Eagles play on a farm, in terms of controlling hyrax numbers and distribution, outweighs the cost of occasional lamb predation by a factor of 155 times (Davies and Ferguson 2000). Incidents of Verreaux’s Eagle poisoning, and capture in gin traps have been reported (Anderson 2000).

Anderson at al. (1997) reported that Verreaux’s Eagle is one of the four raptors most likely to drown in reservoirs. Urbanisation is a threat, particularly if it results in a decrease in the prey base or an increase in disturbance. Allan (1984), in his study of Verreaux’s Eagle in the Magaliesberg, reported that most breeding failures were human induced. On the Cape Peninsula there may have been up to 5–7 breeding pairs in the 1970s (Jenkins and van Zyl 2005). Although it is unclear how many of the historical nest sites were active at any one time, there was certainly at least two pairs until 2004, which have since been reduced to one pair. This is likely due to a loss of hunting areas and disturbance due to urbanisation and increased use of the mountainous areas. The depletion of the primary prey species, Rock Hyrax, through hunting is likely to have a negative impact on breeding success (Monadjem et al. 2003) and has been identified by several authors as a reason for localised declines (Osborne and Tigar 1990, Chiweshe 2007).