Wildlife corridors: Wildlife bridges more effective than culls

Switzerland has 303 supra-regional wildlife corridors. Of these, 47, around 16 per cent, are now largely severed and no longer usable by wild animals. More than half of the remaining corridors are significantly to severely impaired in their functionality. Every year, almost 21,000 medium-sized to large wild animals die on Swiss roads and railways, including over 8,000 roe deer, which statistically means one roe deer every hour. More than 100,000 amphibians are run over each year. Over 100 people are injured annually, and the property damage runs into the tens of millions.

What recreational hunters make of this is remarkable: they declare themselves the solution to the problem. Kills, the argument goes, reduce wildlife populations and thereby wildlife accidents. Preventing wildlife damage on roads serves as a legitimising formula for recreational hunting, especially where other justifications no longer hold. Yet science, practice and experience from Switzerland and Europe clearly show: the effective answers to habitat fragmentation and wildlife accidents are wildlife bridges, wildlife crossings, scent fences, wildlife warning systems and consistent spatial planning, not kills.

This dossier shows why the fragmentation of habitats is a structural problem that requires structural answers, why recreational hunting does not solve the problem but in part aggravates it, and why Switzerland, despite a good legal foundation, lags decades behind what is needed.

You can find more background on the recreational hunting lobby's arguments in the Hunting myths dossier: 12 claims you should examine critically.

What awaits you here

• Habitat fragmentation: what it means and why it is the central wildlife problem of our time. How roads, settlements and railway lines cut animal habitats into ever smaller islands, what this means for populations, genetics and chances of survival, and which species are particularly affected.
• 303 corridors, 47 severed: the state of Switzerland's wildlife corridors. What the FOEN inventory shows, where the biggest gaps lie, why national roads form the greatest barrier, and how far remediation has progressed.
• Wildlife bridges and wildlife crossings: what they can do and what the research says. Why green bridges are effective for all terrestrial animal groups, what 2,300 wild animals per bridge per year means, and which factors decide success or failure.
• Wildlife-vehicle collisions: 21,000 deaths a year and the hidden figure. What Swiss wildlife collision statistics show: which groups of people are harmed, what costs arise, and why the official figures are systematically too low.
• The hunting argument: “Kills prevent wildlife collisions.” Why this claim does not hold up scientifically, why drive hunts and driven hunts can temporarily increase accident risk, and what studies show about population dynamics and road safety.
• Alternatives that work: scent fences, reflectors, wildlife warning systems, speed reductions: Which non-lethal measures show up to 83 per cent fewer wildlife collisions in studies, how technical wildlife warning systems work, and why a 60 km/h limit on critical stretches saves lives.
• Spatial planning as a solution: what consistent habitat connectivity means: how Pro Natura, FOEN and the cantons secure corridors, what the Biodiversity Action Plan provides for, and why the remediation of Swiss wildlife corridors will still take decades.
• What needs to change: Concrete political demands: a remediation obligation with a deadline, mandatory wildlife warning systems, speed reductions, a spatial planning reservation.
• Talking points: Answers to the most common justifications used by the recreational hunting lobby.
• Quick links: All relevant articles, studies and dossiers at a glance.

Habitat fragmentation: the central wildlife problem of our time

Wild animals need connected habitats. They move daily between feeding and resting places, seasonally between summer and winter ranges, and across generations so that young animals can disperse, populations can exchange genes and species can colonise new areas. What was once taken for granted is no longer possible for many species in Switzerland and across Central Europe: roads, railway lines, settlements, channelled watercourses and intensively farmed land have cut the landscape into ever smaller islands.

The consequences are serious. Isolated populations lose genetic diversity because there is no longer any exchange with neighbouring populations. Local events such as a harsh winter, a disease or an extreme weather event can wipe out entire populations if no immigration from neighbouring areas is possible. Species that need large habitats or depend on seasonal migration lose further options with every new road and every new settlement area. After recreational hunting, road traffic is the second most common known cause of death for large wild animals in Switzerland (Wildlife collisions in autumn).

This is not a niche concern of nature conservation. It is the fundamental structural problem of wildlife ecology in Switzerland, and it will not be solved by a single kill. Anyone who wants to talk seriously about wildlife protection, species conservation and road safety must start here, not with the hunting licence.

More on this: Switzerland hunts, but why still? and Hunting and Animal Welfare: What the Practice Does to Wild Animals

303 corridors, 47 interrupted: the state of Switzerland's wildlife corridors

The Federal Office for the Environment (FOEN) has inventoried 303 supra-regional wildlife corridors in Switzerland. These corridors connect woodland, waterways and near-natural areas and form the backbone of wildlife mobility in Switzerland. The result of the latest survey is sobering: only around 28 per cent of the corridors function largely without restriction. 47 corridors (16 per cent) are largely interrupted and can no longer be used by wild animals. More than half, namely 171 corridors, are significantly to severely impaired in their functionality.

The greatest barrier is formed by the national roads. Since 2003, the Federal Roads Office (FEDRO) has been working together with FOEN and the cantons on restoring those wildlife corridors that are crossed by national roads, 41 corridors of supra-regional importance in total. According to FEDRO's interim assessment of July 2025, only 54 per cent of them have been restored or are being implemented, and 44 per cent are at the planning stage. Progress is slow: in 2021 there were 44 wildlife overpasses in Switzerland; the first were built in 1992 in the canton of Thurgau over the new A7. Further crossings, underpasses and specialised small-animal passages are being added, but the restoration will take decades, not years. In the canton of Zurich, the current restoration programme covers 50 wildlife corridors and is planned in three stages over 24 years, from 2024 to 2044.

No wildlife population caused this situation, and no kill will fix it. It is the result of decades of spatial planning failures, and it demands spatial planning corrections.

More on this: FOEN: Wildlife corridors and wildlife crossings and Pro Natura: Clear passage for wild animals

Wildlife bridges and wildlife crossings: what they can do and what the research says

Wildlife bridges and wildlife crossings work. This is not the opinion of nature conservation associations, but the result of decades of research. A meta-analysis that evaluated green bridges in Germany, the Netherlands, France and Switzerland concludes that green bridges are suitable for all terrestrial animal groups to compensate, at least locally, for the fragmentation effects of transport infrastructure. They are most effective when they serve not merely as narrow crossing corridors but are integrated into the home range of the respective species.

The figures are impressive: on a green bridge over the A11 motorway in Brandenburg, almost 2,300 wild animals were recorded between May 2005 and April 2006. The crossing was used not only by larger wild animals but also by invertebrates such as butterflies, spiders and beetles. A monitoring study by the Forest Research Institute of Baden-Württemberg at 66 wildlife crossings, ranging from large overpasses to small-animal culverts, documents that bridges are suitable as crossing aids and as habitat for a wide variety of species groups and make a significant contribution to connectivity. For the European wildcat in Luxembourg, DNA analysis proved that at least 9 different individuals used a single wildlife bridge as a migration corridor.

Width is decisive for success. The wider a bridge is, the better it is accepted. Narrow bridges without cover are avoided by shy species. A bridge at least 50 metres wide with near-natural planting achieves significantly higher usage figures than narrow 'budget models'. This has consequences for planning: those who economise on wildlife bridges economise on effectiveness.

More on this: Canton of Zurich: Wildlife corridors and FOEN Functional monitoring of wildlife crossings (PDF)

Wildlife collisions: 21,000 deaths a year and the unrecorded cases

According to official statistics, almost 21,000 medium-sized to large wild animals die on Swiss roads every year, including over 8,000 roe deer, as well as foxes, badgers, brown hares, wild boars and the occasional red deer. More than 100,000 amphibians, mainly frogs and toads, are run over each year. Around 90 per cent of the accidents occur on roads, the rest on railways. In addition, over 100 people are injured every year, and the material damage from reported insurance claims alone runs into tens of millions: insurers such as AXA and Helvetia report thousands of damage claims each year.

These figures must be read with one crucial caveat: they are underestimates. Only those accidents that are reported to a hunting supervisor or an authority are recorded. Smaller animals, nocturnal species and accidents on minor roads are often missing. In the canton of Zurich alone, around 2,800 wild animals died in road traffic in 2023, and that includes only reported cases. The number of unrecorded cases across Switzerland is likely to be considerably higher than the official 20,000. Particularly accident-prone are the regions of the Jura, Fribourg and the Grisons, as well as the Weinland and the lakeside municipalities in Zurich.

What these figures also show is that the problem is not primarily about wildlife populations as abstract numbers, but about individual animals that die on a road at night, often after a long death struggle, far from any vet, unnoticed by the authorities and the public.

More on this: Dossier: Hunting and Animal Welfare and Wild animals, mortal fear and lack of stunning

The hunting argument: “Kills prevent wildlife accidents”

The argument is an old one and is repeated persistently: fewer wild animals mean fewer wildlife accidents, so kills are supposedly a means of road safety. At first glance this sounds plausible. On closer inspection, however, it does not stand up empirically or ecologically.

First, population-ecology studies show that intensive hunting can reduce wild animal populations in the short term but not permanently, because losses are compensated by higher reproduction rates. This applies especially to roe deer and wild boars: the population regulates itself through the carrying capacity of the habitat, not through kill figures. Hunting briefly creates space for young animals and thereby raises the reproduction rate. Second, research shows that driven hunts and drive hunts actively flush wild animals and throw them into panic. Hunted animals cross roads in mortal fear that they would otherwise avoid. PETA notes: “Hunters share responsibility for many wildlife collisions. During hunts, especially large driven hunts, the animals are flushed out. They flee and run in mortal fear across roads and into settlements.”

Third, recreational hunting evidently does not prevent wildlife collisions: the highest accident rates in the Mobiliar analysis for 2021 to 2025 are recorded in Thurgau, Grisons and Jura, all cantons with recreational hunting (Wildlife collisions in autumn). What makes the difference are structural measures: speed reductions, wildlife warning systems, habitat planning. This shows that road safety and wildlife protection are planning tasks, not hunting tasks.

More on this: Hunting myths: 12 claims you should scrutinise critically and Hunting and animal cruelty

Alternatives that work: scent fences, reflectors, warning systems, speed reductions

Between the extremes of “doing nothing” and “shooting wild animals” lies a broad spectrum of scientifically tested, non-lethal measures for reducing wildlife collisions, which in their overall effect are far more efficient than kills.

A meta-analysis of 50 studies shows that wildlife fences combined with crossing structures reduced the number of large mammals killed on roads by 83 per cent, wildlife warning systems with animal detection by 57 per cent, whereas wildlife warning reflectors reduced it by only 1 per cent (Rytwinski et al. 2016, PLOS ONE). A field study by the universities of Göttingen and Zurich on 150 road sections found no effect for blue reflectors (Benten et al. 2018, Accident Analysis & Prevention). Acoustic wildlife warning systems, which respond to vehicle movements and emit ultrasonic signals, have proved effective at accident hotspots. In the canton of Zurich, an improved warning system is being trialled on Lake Zurich, specifically targeted at the stretches of road with the most accidents.

Speed limits on critical road sections, in particular 60 km/h at night on known crossing stretches, are easy to implement and significantly reduce both the likelihood of collisions and the severity of accidents: a 20-kilogram roe deer has an impact weight of around one tonne at 100 km/h. Wildlife fences along national roads do prevent crossings, but at the same time they intensify habitat fragmentation; they therefore only make sense in combination with wildlife crossings, never as a stand-alone measure. Acoustic deterrent methods such as the “Wildschweinschreck” (wild boar scarer) tested by the ZHAW show promising results in agriculture and could durably influence animal behaviour near roads without injuring a single animal.

More on this: Alternatives to Hunting: What Really Helps, Without Killing Animals and Initiative calls for «Game wardens instead of hunters»

Spatial planning as a solution: what consistent habitat connectivity means

Wildlife corridors are anchored in Swiss law: the network of corridors is a statutory mandate, and their restoration is part of the action plan for the Confederation's biodiversity strategy. The FOEN, FEDRO and the cantons work together. The foundations are good.

The problem is the pace. The restoration of the 41 wildlife corridors along national roads has been under way since 2003, that is, for more than 20 years, and is still not complete. In the canton of Zurich, the restoration programme for 50 corridors is designed to run for 24 years. Pro Natura has been demanding for years that impaired or interrupted corridors be made continuous again, and that the movement needs of wild animals be taken into binding account from the outset when planning new infrastructure. The Federal Office for the Environment is accelerating the restoration programmes as part of the biodiversity strategy. That is a step in the right direction, but it must not obscure the fact that for every restored crossing, new fragmentation arises, as long as spatial planning and building law do not enshrine a consistent principle of corridor protection.

What a truly consistent approach would mean: a corridor reservation binding under federal law for all projects with spatial impact, an accelerated restoration programme with clear deadlines instead of decades-long plans, an obligation to install wildlife warning systems on all statistically accident-prone stretches, and the consistent strengthening of near-natural land use in corridor zones, in order to ensure that migration routes remain passable even between bridges and crossings.

More on this: FOEN: Wildlife corridors and Canton of Lucerne: Wildlife corridors and wildlife crossings

What needs to change

• A reservation for wildlife corridors, binding under federal law, for infrastructure projects: Today, wildlife corridors must be taken into account in new road, rail and settlement projects, but the legal obligation is patchy. A clear statutory basis is needed that in principle prevents any new fragmentation of existing or planned corridors and ties exceptions to strict compensation requirements.
• Accelerated restoration programme with deadlines: The ongoing restoration of the 41 wildlife corridors along national roads must be given binding completion deadlines. A 24-year plan is not a restoration programme but a brush-off. At the current pace, severed corridors will be restored decades too late.
• Mandatory wildlife warning systems on accident-prone road sections: The cantons keep wildlife accident statistics. This data must be systematically analysed and, on road sections with frequent accidents, used as grounds for mandatory wildlife warning systems, scent fences or speed reductions. A wildlife accident hotspot without countermeasures is an avoidable decision.
• Speed reductions on crossing sections: On road sections that cross known wildlife crossings, especially at dusk and during the night, 60 km/h must be the standard speed limit. Reducing the impact weight lowers the severity of accidents for animals and humans alike.
• Integrated wildlife management instead of kill quotas: Cantonal hunting authorities and spatial planning authorities must work more closely together. Wildlife management can no longer mean setting kill figures. It must mean connecting habitats, creating buffer zones and systematically prioritising non-lethal solutions to conflicts.
• Complete, publicly accessible wildlife accident statistics: Not all cantons publish comparable wildlife accident figures. Uniform, publicly accessible monitoring with binding reporting obligations creates the data basis needed for evidence-based measures.
• Template motions: Wildlife corridors instead of kills, Template texts for hunting-critical motions and Protecting protective forests from recreational hunting

Talking points

“Fewer wild animals through kills means fewer wildlife accidents.” That holds true in the short term and locally, in certain individual circumstances. In the long term, wildlife populations offset losses through higher reproduction rates; numbers recover quickly. There are also indications that driven hunts and drive hunts temporarily increase the risk of accidents: panicked animals cross roads in mortal fear that they would otherwise avoid. Thurgau, Grisons and Jura, all cantons with recreational hunting, show the highest wildlife collision rates in the Mobiliar analysis for 2021 to 2025.

«Wildlife bridges are too expensive, recreational hunting is far cheaper.» Depending on its width and location, a wildlife bridge costs several million francs. But it lasts for decades, improves biodiversity, permanently reduces accidents and creates no new problems. Culls are periodic, generate follow-on costs through increased reproduction and do nothing to solve the underlying problem, the fragmentation of habitat. Anyone who calls wildlife bridges too expensive must ask why they do not set against them the costs of hunting, wildlife collision damage running into tens of millions, and long-term biodiversity losses.

«Wildlife corridors are pointless if the animals do not use them.» Research shows the opposite: wildlife bridges are used by all terrestrial animal groups, from large mammals to invertebrates. What matters is width, planting and the connection to near-natural areas on both sides of the crossing. Narrow or poorly designed bridges do indeed work less well. That is an argument for better planning, not against wildlife bridges as such.

«Hunting regulates wildlife populations that would otherwise get out of hand.» No wildlife population «gets out of hand» unless humans have altered its habitat, its natural enemies or its food supply. Where wildlife populations really do cause problems, non-lethal measures such as deterrent systems and habitat adjustments are often more effective and longer-lasting than culls, which do not address the underlying problem.

«Pro Natura and other nature conservation associations support hunting as a tool.» Pro Natura consistently campaigns for wildlife corridors, green bridges and spatial planning. Where nature conservation associations do not categorically reject individual hunting measures, this is not support for recreational hunting, but the result of pragmatic compromises in a system that offers no better alternative. As soon as non-lethal alternatives are available, the hunting argument loses its footing in nature conservation.

«Switzerland has one of the best wildlife corridor systems in the world.» Switzerland has a good inventory and a sound legal foundation. But 47 largely interrupted and 171 severely impaired corridors out of 303 supra-regional connections are no success story. The restoration programme has been running since 2003 and is designed to last for decades. What is needed is more speed, more funding and more political will, not self-congratulation.

Quick links

Articles on Wild beim Wild:

• Hunting and Animal Welfare: What the Practice Does to Wild Animals
• Alternatives to Hunting: What Really Helps, Without Killing Animals
• Switzerland hunts, but why still?
• Initiative calls for «Game wardens instead of hunters»
• Hunting accelerates poaching: study refutes old superstition
• Hunting in Switzerland: fact check, types of hunting, criticism
• Autumn wildlife collisions: hunting stress also named as a contributing cause
• Clock change: why the week after 25 October is dangerous for wild animals
• Hunting fact-checked: effects on wild animals, ecology and society

Related dossiers

• Wildlife corridors and habitat connectivity: why wildlife bridges and spatial planning are more effective than kills
• The cultivated landscape as myth
• Hunting laws and oversight: why self-supervision is not enough
• Alternatives to recreational hunting
• Geneva and the hunting ban
• The game warden model – professional wildlife management with a code of honour

Our Standard

Wildlife corridors, wildlife bridges and consistent spatial planning are not romantic conservation ideas. They are the only answers that actually address the underlying problem of habitat fragmentation. Kills do not solve this problem. At best they mask it temporarily and create new problems: increased reproduction rates, stress-induced abnormal behaviour and panic flight across roads. The canton of Geneva has shown since 1974 that wildlife management without recreational hunting is possible.

A wildlife policy that takes biodiversity and road safety seriously invests in wildlife bridges, speeds up the restoration of interrupted corridors, mandates wildlife warning systems at accident hotspots, and stops offering kills as a universal tool for problems that call for structural solutions. Switzerland has the legal foundation and the scientific knowledge to do this. What is missing is political will and speed. This dossier is updated continuously as new studies, planning reports or political decisions require.

More on the topic of recreational hunting: in our hunting dossier we bring together fact checks, analyses and background reports.