Afrotropical raptors were the focus of a wind farm study in Kenya.
A five-year study at a 100-megawatt facility showed that different species exhibit different turbine avoidance capabilities. The high-resolution flight paths of 15 individual birds across four species were analyzed. The result was the first record of empirical meso-scale avoidance rates for African prey birds.
Global conservation models are being challenged. The study shows that collision risk depends on foraging habits, altitudes, and spatial awareness across the different species.
Buzzards, eagles, and vultures have different flight profiles
The 15 birds of prey tracked in the study were nine Augur buzzards, two African hawk-eagles, one martial eagle, and three Rüppell’s vultures. The wind farm comprised 60 turbines of rotor heights between 82 and 443 feet spread across 27 square miles.
The different species had different avoidance rates. African hawk-eagles’ meso-scale avoidance rate was 74.4 percent within a 180-foot horizontal risk radius. Martial eagles followed with a rate of 68.5 percent. These eagle species spent around 23 percent of their time flying at about the same height as the rotors. This totaled approximately 52 minutes daily.
The Augur buzzards’ avoidance rate was the lowest at 48.9 percent. They prefer to look for terrestrial prey at low altitudes, spending half their flight time inside the wind farm airspace. Of that, 50 percent was spent directly in the rotor sweep zone. Daily exposure averaged at 74 minutes. The combination of low avoidance and exposure over longer periods meant that the Augur buzzard was far more vulnerable to turbine blade strikes.
Global models should be applied with caution
The spatial usage for Rüppell’s vultures was completely different from those of eagles and buzzards. Just one percent of their flight time occurs above the energy facility’s boundaries. Vultures fly at greater heights; just three percent of the flights occurred within the 82- to 443-foot rotor sweep range. That translates to less than two minutes a day of exposure.
The tracking showed that the birds were using the area predominantly as a high-altitude flight route from their nesting areas nine miles west of the energy facilities to other feeding areas somewhere farther. The high accuracy of telemetry made it possible to update data from earlier human ground observations, which often overestimated the low-altitude exposure risk of vultures.
The new information also shows the peril of using collision models on a global scale. Renewable energy planners often rely on baseline assumptions that estimate bird avoidance rates at 98 to 99 percent, rather than direct collision risk. Avoidance rates measure evasive behavior, while actual collision risk must be modeled separately based on species exposure, flight height, turbine operation, and real-world behavior.
Global collision risk cannot be calculated in general terms for Afrotropical species because morphological, dietary, and flight characteristics play a role in the collision risk.
Targeted operational risk mitigation is critical
The high-resolution tracking went beyond recording horizontal movements. Researchers were also able to record flight adjustments in three dimensions.
Within a risk distance of 180 feet, martial eagles and African hawk eagles both changed their altitudes. They demonstrated vertical avoidance inside and slightly above the range of the rotors.
Augur buzzards, on the other hand, showed unique attraction to different levels of the turbines. They were good at avoiding the 180- to 360-foot zone, recognizing the danger of the moving blades. However, they were attracted to the areas closer to the turbine bases under the blades. This draws hunting buzzards closer to operational hazards.
Generic raptor conservation planning is not enough
Generic planning based on outdated or non-targeted conservation information is not enough for comprehensive and effective wind energy planning. One of the factors for developers to prioritize is micro-siting. This means turbines should be placed far from active nesting sites and core territories for buzzards and eagles.
There are different protection methods at existing operators’ disposal, such as automated shutdowns in the event of approaching birds, painting the blades in order to increase their visibility, and removal of prey carcasses.
Africa may be behind in the transition to renewable energy, but development is taking place, and the continent’s biodiversity deserves as much consideration as anywhere else’s.
All the details of the study can be found here: Kimani, D. K., McCabe, J. D., Ndiritu, G. G., Kimuyu, D., Bennun, L., Downing, T. A., & Buij, R. (2026). Meso‐scale avoidance of wind turbines by four raptors at a Kenyan wind farm. Ecological Solutions and Evidence, 7(3).
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