Preprint - LIFE EUROKITE Study on Red Kite Mortality
The LIFE EUROKITE project is pleased to announce the preprint of a major scientific paper titled “High human-caused mortality in GPS-tracked red kites across Europe”. The study is currently under review in npj Biodiversity and has not yet undergone a formal peer-review-process.
Nevertheless, the study represents the most comprehensive analysis to date of red kite (Milvus milvus) mortality across continental Europe. Between 2013 and 2022, researchers tracked 2,346 red kites using high-resolution GPS satellite telemetry, enabling the detection and investigation of 979 mortality events. Illegal killing, particularly poisoning, was identified as the primary non-natural cause of death, with poisoning alone accounting for 25% of all cases. Causes include use of rodenticides, predator control measures, and game management practices.
As a key ecosystem indicator species, the red kite plays an important role in European biodiversity monitoring.
This work sets a new benchmark in the use of advanced tracking technologies to inform wildlife conservation and demonstrates the critical importance of transboundary collaboration to reduce raptor mortality and ensure the long-term survival of the species.
Preprint: High human-caused mortality in GPS-tracked red kites across Europe, 2026
https://www.researchsquare.com/article/rs-9705180/latest
Statements that refer to the results
- Using an unprecedented dataset and the newly developed LEAP method (Connor et al. 2025), we demonstrate that human-caused mortality significantly outnumbers natural mortality in European kites, which are an important bioindicator species of ecosystem health. Utilizing GPS tracking data collected at a continental scale, our approach overcomes limitations associated with commonly used methods, including ring recoveries and opportunistic carcass collections, providing more reliable inferences about patterns of mortality causes. Major threats to kites include poisoning, road and rail collisions, collisions and electrocutions on power lines, illegal shooting and trapping, and wind turbine collisions. We report significant differences in risk exposure and mortality contributions of poisoning, power line mortalities and shooting across European countries.
- Illegal killing (poisoning, shooting, trapping) is the main cause of red kite mortality.
- Poisoning, driven by rodenticides, livestock predator control and game management, was the most prevalent anthropogenic mortality cause for kites across Europe, accounting for a quarter of all cases. To combat the illegal use of poisons and deliberate killing of raptors and large carnivores, targeted actions are needed. These should include adjusting existing laws, ensuring stronger enforcement, and launching media campaigns to raise public awareness and educate hunters and farmers in poisoning and shooting hotspots.
- Wildlife is poorly protected against vehicle collisions along roads and railways, except some sections of highways and high-speed railways. To address this prevalent issue, investigating effectiveness of implementing protective measures such as targeted road signage, enhanced carcass removal programs, and increased use of wildlife detection systems might help reduce collision rates in the future.
- Mitigation strategies are essential for the EU green energy transition. Across all studied European countries, wind turbines account for a relatively small proportion of mortality related to human infrastructure (3.8% for wind turbines versus 10.9% for road traffic, and 5.4% for rail traffic). Power lines, which is a type of infrastructure accompanying wind turbines and other power sources, accounted for 9.9% of the mortality. The European Green Deal will lead to an increase in onshore wind turbines and possibly in associated overhead power lines across much of Europe. Countries that currently have few turbines expect growth, while countries with more developed wind energy infrastructure - such as Germany - are anticipating repowering to fewer but larger turbines.
Although our results show that wind energy contributed relatively little to kite mortality at the European scale throughout the study period (2013 – 2022), the impact of wind turbine collisions on kite mortality might locally exceed the mortalities observed in this study. These regional studies found substantial numbers of red kites killed by wind turbines based on carcass searches and opportunistic carcass discoveries, but this methodology cannot be used to assess proportional mortality relative to other causes. The LEAP method used in our study, however, allows for comparisons of different mortality causes and their prevalence.
Expansion of wind energy will increase kites’ exposure to collisions, and mitigation of this risk is needed through the careful design and placement of turbines. Various mitigation methods exist, such as bird detection-driven curtailment for Golden Eagles (Aquila chrysaetos) or predictive curtailment during key periods (e.g., migration peak). A recent GPS tracking study suggests that turbines with higher ground clearance might reduce collision risk for kites by decreasing the overlap between their flight altitudes and the hazardous rotor-swept zone, and that at equal ground clearance, larger rotor diameters reduce collision risk per unit of power capacity (although the effect may be different for other species). This highlights the need for vigilance as wind energy infrastructure expands and underscores that effective mitigation strategies to reduce collisions involving kites and other sensitive species merit further investigation.
While mortality at wind turbines occurs only through collision, mortality on power lines includes electrocution and collision. Electrocution can be effectively mitigated by retrofitting power lines, for example in Germany where bird-friendly designs are required by law. Regulations and conservation efforts have reduced electrocution and collision rates in Spain, but these mortality causes remain frequent across the rest of the continent (of all mortality at power lines 75.8% were due to electrocution). While retrofitting reduces or even eliminates electrocution risk, collisions with overhead cables persist. Installation of bird flight diverters is a common mitigation strategy, but burying cables is most effective to prevent both collisions and electrocution. Such mitigation is demonstrated in eastern Austria, where 66% of new medium-voltage lines are now built underground. - As energy infrastructure continues to expand, scientifically informed mitigation strategies are essential to avoid electrocution on pylons of medium-voltage power lines along with collision at wind turbines and on power lines. Legislation that is effective on-the-ground, e.g. power line retrofitting, is required to attenuate the impact of energy infrastructure on red kites and other wildlife.
- Predation is a common natural cause of mortality in red kites. Relatively high predation rates are likely a consequence of high density and activity of predators that prey on red kites. The high incidence of predation may also be influenced by secondary factors, such as illness or poisoning, which increases vulnerability to predators.
- Solutions must address the heterogeneity of threats across appropriate scales. Analysis of standardised mortality risks across countries for red kites highlights important geographical differences with significant implications for conservation strategies. Solving these issues requires both country-specific location conservation actions and complex, cross-border conservation initiatives involving scientific, political, business, and societal partnerships at various scales to mitigate human impacts on wildlife across Europe.
- Mortality causes were similar for subadult and adults. This highlights the importance of protecting not only adult or breeding birds but also subadults, whose vulnerability could significantly affect population dynamics.
- Differences in mortality causes between the summer country and country of death highlight the diverse risks birds face during migration.
- At the broader international scale, collaboration between law enforcement agencies, increased awareness of major threats to red kite populations and education campaigns designed to increase nature engagement and protection across countries, will ensure that red kite populations are protected into the future.
- Study limitations and future perspectives:
- The analysis only included primary mortality causes.
- Differences in exposure levels between countries could not be taken into account, e.g. kites in countries with a higher turbine density could be more vulnerable to turbine collisions.
- Some incidences of sudden tag stops may be related to shooting or road and rail collisions, subsequently underestimating anthropogenic mortality.
- As tagged birds were not sampled randomly, the analysed red kites may not represent the entire European population proportionally, therefore we calculated proportions of mortality causes weighted by abundance. Results are meaningful for key countries such as Spain and Germany, but sample sizes in other countries (e.g., Italy, Luxembourg, Belgium) were too small for analyses. Increased tagging efforts of red kites or other indicator candidate species are needed in these regions.