In South Africa, researchers painted two red stripes on one turbine blade; a preprint suggests bird fatalities fell by a median 83% at four treated turbines

Wind turbines offer a cleaner alternative to fossil fuels, but their rotating blades can pose a collision risk to birds, including raptors that hunt or soar near wind farms. Researchers in South Africa have tested a simple way to address this problem by painting two broad red stripes on one blade of selected turbines. According to a 2026 preprint on red-patterned wind turbine blades, the experiment at the Umoya wind farm near Hopefield in South Africa's Western Cape found a median 83% reduction in bird fatalities at four treated turbines. The approach aims to make moving blades more visible to birds, potentially helping them avoid collisions without requiring turbines to be stopped. However, the findings remain preliminary, and further trials are needed to establish whether the method works consistently across different wind farms and bird species.How researchers tested the red stripesThe study, titled Crouching tiger, hidden dangers: Avian fatality rates reduced by red-blade patterning at a species-rich African wind farm, examined a 37-turbine facility in a region known for its rich birdlife. For 2023, two large Signal Red stripes were painted on one rotor blade at each of four wind turbines known to kill the highest number of birds. The rest of the turbines remained as they were originally. These stripes were supposed to provide more contrast between the moving blades and their background environment. Each stripe was about a quarter of the blade’s length, with a white section between them. The red colour was chosen in part because South African civil aviation regulations restrict the use of black paint.Bird mortality data were collected before and after treatment through an experiment involving four neighbouring turbines, along with another set of 12 control turbines. This allowed them to test whether mortality was lower at the patterned turbines than at the control turbines. The observation period lasted 32 months, beginning when the patterned turbines were installed in April 2023. Statistical models were used to measure the impact of treatment, taking into account the differences between the two turbine types.What the results revealedThe results showed a substantial difference between the treated and untreated turbines. Over 32 months, 25 bird fatalities were recorded across the 20 turbines included in the comparison, with two occurring at the four turbines with patterned blades and 23 at the 16 untreated control turbines. Bayesian analysis estimated a median 83% reduction in bird fatality rates at the patterned turbines. However, the estimate had wide credible intervals, ranging from 14% to 98% when compared with the four nearest-neighbour controls and from 30% to 97% when compared with all 16 control turbines.Another question is whether birds that avoid the painted blades might collide with nearby unpainted turbines. The South African study found little evidence of an increase in fatalities at neighbouring turbines, although the small sample size meant that this possibility could not be ruled out conclusively. These findings are consistent with a 2020 study published in Ecology and Evolution. Conducted at Norway's Smøla wind farm, the research found that painting one of a turbine's three blades black reduced the annual bird fatality rate by 71.9% compared with neighbouring unpainted turbines.The researchers also found no evidence that birds avoiding the painted turbines were being redirected towards nearby unpainted ones. The South African experiment extended this approach to a more species-rich setting, using red stripes rather than a solid black blade. The contrast may have made the moving blades easier for birds to detect, while the colour itself may also have played a role. However, the experiment did not establish which visual feature was primarily responsible for the reduction in fatalities.A promising step, but more evidence is neededThe appeal of blade patterning is that it is relatively simple. While a radar detection system or automatic shut-down mechanism relies on constant monitoring, the painted blades do not. The scientists proposed that this method could provide an effective way of lowering the number of birds killed in wind farms without resorting to more costly methods. However, painting turbine blades is itself a difficult task. Special equipment may be required to paint the blades of the turbines installed at heights above the ground, and it should be done in proper conditions. The painting process could perhaps be incorporated into turbine blade production.There were only four turbines used in the treatment, and the report was issued as a preprint article in May 2026; consequently, the research had not been formally peer-reviewed when it was published. Further experimentation with larger samples and in different terrains, climates, and bird populations is needed before the decrease can be treated as a general finding. For now, the experiment offers an encouraging sign that wind farms may be able to reduce bird deaths.You use AI every day. Now get your AI Quotient. Take the AIQ test.