High-Speed Trains Pose Hidden Threat to Spain’s Birds
New research finds Great Bustards and Eagle-owls among victims of collisions, raising questions over how rail expansion can be made safer for wildlife
Birds on the line
Spain’s rapidly growing high-speed railway network, promoted as a green alternative to air and road travel, is exacting an unseen toll on some of Europe’s most iconic birds. A new study has documented significant collisions involving both Great Bustards and Eurasian Eagle-owls along a 10 km stretch of track in Toledo province. Over two years of monitoring, researchers found 19 Bustards and 27 Eagle-owls dead on the line.
Great Bustards, the heaviest flying birds in Europe, were killed at specific crossing points where they flew across the tracks as part of daily movements between feeding areas. In contrast, Eagle-owls appeared to die while hunting rabbits that thrive on railway verges. The results reveal two distinct collision risks linked to species behaviour: predictable flight corridors for Bustards, and opportunistic hunting by owls.
A global conservation concern
The Great Bustard is globally listed as Vulnerable, with Spain home to most of the world’s 22,000–24,000 individuals. The study highlights how railways cut across the very farmland and grassland habitats on which these declining birds depend. By contrast, the Eagle-owl, though more widespread and currently stable in Spain, faces heightened risks from train strikes due to its hunting habits around rabbit-rich verges.
The researchers warn that these findings could apply to other large birds worldwide. Bustards in Asia and Africa, as well as large owls and raptors elsewhere, may face similar threats as high-speed rail expands globally under projects like Europe’s Green Deal and China’s Belt and Road Initiative.
Rethinking railway design
The study suggests mitigation must be tailored to each species. For Bustards, predictive models could help planners reroute lines away from key habitats and flight paths. Where existing lines bisect Bustard ranges, anti-collision barriers trialled in Europe – poles encouraging birds to fly higher – could help reduce mortality. For owls, measures would need to focus on managing rabbits and vegetation on railway verges to make them less attractive hunting grounds.
Without action, researchers caution that railway mortality could undermine conservation gains for threatened species, while also posing safety risks. A collision with a 15 kg Bustard flock could have consequences not just for birds but also for train operations. The study’s authors call for bird-sensitive impact assessments to be built into all new high-speed rail planning worldwide.
A balancing act for the future
The research underscores the dilemma at the heart of transport policy. High-speed rail is championed for cutting carbon emissions and reducing reliance on cars and planes. But without careful planning, the very landscapes that benefit most from climate action – open farmland, grassland, and scrub – could become deadly traps for wildlife.
As Europe prepares to triple its high-speed rail network by 2050, the challenge will be to ensure that reducing carbon emissions does not come at the cost of bird conservation.
Oct 2025
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