When Borders Kill: How National Sovereignty Fails Migratory Animals

In October 2022, a juvenile bar-tailed godwit tagged as B6 by the US Geological Survey lifted off from the mudflats of southwestern Alaska and flew south over the Pacific Ocean. Eleven days later, having covered more than 13,500 kilometres without rest, food, or water, it landed in Tasmania, Australia, setting the world record for the longest documented nonstop flight by any land bird. The flight crossed no national border in the conventional sense. For most of its journey, B6 was over open ocean, beyond any state's jurisdiction. Yet the species' survival depends entirely on a chain of coastal wetlands scattered across the countries of the East Asian-Australasian Flyway, from the Yellow Sea mudflats of China and South Korea to the mangrove estuaries of Southeast Asia.

Every one of those wetlands falls under a different sovereign jurisdiction. Every one is governed by different laws, different priorities, different development pressures. The bird does not know this. The bird cannot know this. And that ignorance is the most concise diagnosis of a structural failure in global governance that has been growing since 1648.

The Westphalian Trap

The Peace of Westphalia, signed in 1648 to end the Thirty Years' War, established the foundational principle of the modern international order: sovereign states exercise exclusive authority within their territorial boundaries. For nearly four centuries, this principle has structured diplomacy, law, and war. It works reasonably well for matters that stay within borders. It fails catastrophically for matters that do not.

Migratory animals are the clearest case of that failure. The 2024 State of the World's Migratory Species report, the first comprehensive global assessment published by the United Nations Environment Programme, found that 44 percent of CMS-listed migratory species show population declines. More than one in five CMS-listed species are threatened with extinction. The decline rate for migratory species outpaces that of non-migratory species by a significant margin, and the primary driver is not poaching or climate change alone. It is habitat loss along migration corridors that span multiple jurisdictions, where protection in one country means nothing if the next country along the route has paved over the stopover site.

This is not a gap in policy. It is a design flaw in the system itself. Conservation law is built on jurisdiction. Migration is built on connectivity. The two are structurally incompatible.

Borders Made of Steel

The incompatibility is not only legal. It is increasingly physical. Since 1990, the number of fortified border barriers worldwide has grown from fewer than 15 to approximately 70. These walls and fences were built to control human movement. They kill animals as a side effect.

Along the US-Mexico border, roughly 1,200 kilometres of barrier infrastructure cut through some of the most biodiverse terrain in North America. The Sonoran pronghorn, a subspecies already on the brink, has seen its range severed. Jaguars that historically moved between Mexican and American populations can no longer cross. Ocelots, bighorn sheep, and dozens of reptile and amphibian species face fragmented habitats. The wall was not designed to block them. It blocks them anyway.

In South Asia, India's border fence with Bangladesh now extends over 3,200 kilometres of completed fencing along the 4,097-kilometre border. It cuts through elephant migration corridors in the northeast, forcing Asian elephants into conflict with human settlements they would otherwise bypass. Elephants that once moved freely between the forests of Assam and the Chittagong Hill Tracts now encounter barbed wire and concrete.

In Central Asia, fencing along the borders of Kazakhstan, Uzbekistan, and Turkmenistan disrupts the migration of saiga antelope, a species that has already suffered catastrophic population crashes from disease. The CMS Central Asian Mammals Initiative has identified border infrastructure as one of the primary threats to saiga recovery, but the fences remain because they serve security objectives that outrank ecological ones.

The pattern is consistent. Border infrastructure is built for political reasons. Ecological impact assessments are either not conducted or not heeded. The animals pay the cost of a security architecture they have no stake in.

The Precedent That Worked: How Humanity Governed the Sea and the Sky

The structural problem is not new. Humanity has faced it before, in domains where geography made territorial sovereignty impractical, and has sometimes solved it.

In 1609, the Dutch jurist Hugo Grotius published Mare Liberum, arguing that the oceans could not be owned by any sovereign power. The argument was self-interested, designed to break the Portuguese monopoly on East Indian trade routes, but it established a principle that eventually reshaped international law. By 1982, when the United Nations Convention on the Law of the Sea was finalized after nearly a decade of negotiation, the world had a governance framework for the oceans: Exclusive Economic Zones of 200 nautical miles for coastal states, freedom of navigation beyond them, and the concept of the deep seabed as "common heritage of mankind." UNCLOS is imperfect and contested, but it exists. It has a tribunal. It has teeth.

Airspace followed a similar trajectory. Before the Chicago Convention of 1944, the skies above national territory were an unregulated domain. The convention established the International Civil Aviation Organization and created a system of flight information regions, overflight permissions, and safety standards that made commercial aviation possible. Sovereignty over airspace was retained in principle but constrained in practice by a dense web of bilateral and multilateral agreements.

The most radical example is Antarctica. The Antarctic Treaty of 1959 did not abolish sovereignty claims over the continent. Seven states had made such claims and none withdrew them. Instead, the treaty froze them. It declared Antarctica a zone for peaceful scientific cooperation and prohibited military activity, nuclear testing, and mineral exploitation. For more than six decades, this suspension of sovereignty has held.

Each of these governance innovations was driven by the same structural pressure: physical reality made exclusive territorial control either impossible or self-defeating. The seas could not be enclosed. The skies required coordination. Antarctica could not be divided without conflict. In each case, the international community invented new legal architectures that limited sovereignty in the name of shared access and shared management.

Migration corridors present the same structural demand. No governance innovation of comparable ambition has emerged to meet it.

The CMS Experiment

The closest attempt is the Convention on the Conservation of Migratory Species of Wild Animals, signed in Bonn in 1979 and in force since 1983. The CMS was a genuine intellectual achievement, the first international treaty to recognize that migratory species required coordinated protection across their entire range, not just at endpoints.

But the CMS was built weak by design. It has 133 parties, covering much of Europe, Africa, and Oceania, but three of the world's largest countries by territory and ecological impact are absent. The United States has never joined. China has never joined. Russia has never joined. Between them, these three states control vast stretches of the planet's most critical migration corridors: the Pacific and Atlantic flyways, the Central Asian steppes, the Arctic breeding grounds.

The CMS annual budget runs to approximately three to four million euros per year, a fraction of what a single national park in a wealthy country spends on operations. Its enforcement mechanism consists of non-binding resolutions and voluntary national action plans. Compare this to CITES, which can authorize trade sanctions against non-compliant parties, or UNCLOS, which has the International Tribunal for the Law of the Sea. The CMS has no sanctions. It has no tribunal. It has recommendations.

The convention has produced subsidiary agreements of real value. The Agreement on the Conservation of African-Eurasian Migratory Waterbirds, known as AEWA, covers 255 species across the African-Eurasian region and has 85 parties. EUROBATS protects bat species across Europe. The Memorandum of Understanding on the Conservation of Migratory Sharks covers some of the ocean's most threatened travelers. These instruments create frameworks for information sharing, habitat identification, and coordinated monitoring. What they cannot do is compel a state to protect a wetland that it would rather develop, or prevent a government from building a fence through a migration corridor.

The CMS is a framework convention. It coordinates. It does not govern.

The Sovereignty Reflex

The absence of the United States, China, and Russia from the CMS is not accidental. It reflects a consistent strategic position: these states prefer bilateral arrangements they can control over multilateral frameworks that might constrain them.

The United States manages migratory birds primarily through the Migratory Bird Treaty Act of 1918, one of the oldest wildlife protection laws in the world, supplemented by bilateral treaties with Canada, Mexico, Japan, and Russia. This approach gives Washington direct control over every agreement. Joining CMS would mean accepting obligations defined by a multilateral process in which the US would be one voice among 133.

China takes a similar approach, managing transboundary wildlife through bilateral agreements with neighboring states rather than subscribing to a multilateral framework. Beijing's reluctance to join environmental treaties that imply external oversight of domestic land use is well documented across climate, biodiversity, and now migration governance.

Russia's position has hardened in recent years, as its broader withdrawal from international cooperation has extended to environmental monitoring and research programs. The country controls vast stretches of Arctic tundra that serve as breeding grounds for migratory birds from every continent. Its absence from CMS means these habitats have no multilateral protection framework.

The underlying logic is consistent. National sovereignty over natural resources was affirmed by UN General Assembly Resolution 1803 in 1962, and major powers have treated this as a ceiling, not a floor. They will cooperate on migratory species when it suits them, on their own terms, through instruments they can exit at will. The idea that ecological connectivity might require a permanent limitation on how a state uses its territory remains diplomatically unacceptable.

Where Cooperation Happens Anyway

Yet cooperation does occur, and the cases where it works share instructive features.

The Wadden Sea Trilateral Cooperation, initiated in 1978 when Denmark, Germany, and the Netherlands held their first joint governmental conference on protecting the shared ecosystem, is perhaps the most successful transboundary conservation arrangement for migratory species in the world. The Wadden Sea is a tidal flat ecosystem stretching along the North Sea coast, one of the most important staging areas for migratory shorebirds on the East Atlantic Flyway. Roughly ten to twelve million birds pass through each year, refueling on the invertebrate-rich mudflats before continuing to breeding grounds in the Arctic or wintering sites in West Africa.

The trilateral cooperation works because all three conditions for successful transboundary governance are met: geographic proximity, shared economic interest, and institutional leadership by a regional power. Germany drove the process. The three countries share a coastline and a common interest in managing a resource that supports fisheries and tourism worth billions. The Wadden Sea was inscribed as a UNESCO World Heritage Site in stages between 2009 and 2014, adding an international prestige incentive to the existing economic logic.

In southern Africa, the Kavango-Zambezi Transfrontier Conservation Area spans five countries, Angola, Botswana, Namibia, Zambia, and Zimbabwe, covering approximately 520,000 square kilometres. KAZA is the world's largest transfrontier conservation area and supports the migration of elephant herds, wildebeest, and zebra across national boundaries. It works in part because cross-border wildlife tourism generates revenue that would be lost if borders were closed to animal movement.

The pattern is clear. Transboundary conservation succeeds where states have a direct economic stake in the migrating resource and where a strong institutional actor drives the process. It fails where these conditions are absent, which is to say, it fails in most of the world. The Wadden Sea model cannot be replicated in the Yellow Sea, where China and South Korea face competing development pressures and no trilateral institution exists. KAZA cannot be replicated in Central Asia, where the saiga antelope's migration corridor crosses borders between states with weak conservation budgets and strong security priorities.

The Missing Architecture

What would a governance system adequate to the ecological reality actually require? The elements are not mysterious. They exist in other domains of international law. They have simply never been combined for migratory species.

First, binding corridor protection. UNCLOS created a legal status for maritime zones that limits what coastal states can do within them. An equivalent instrument for migration corridors would designate critical flyways, swim-ways, and land corridors with binding habitat protection obligations. The Kunming-Montreal Global Biodiversity Framework of 2022 took a step in this direction: Target 3 calls for well-connected systems of protected areas covering at least 30 percent of terrestrial and marine areas by 2030, and Target 2 emphasizes restoration to enhance ecological connectivity. But these targets remain aspirational rather than binding.

Second, a financial mechanism. The Green Climate Fund mobilizes billions for climate adaptation. No equivalent exists for ecological connectivity. The cost of maintaining migration corridors is borne almost entirely by the states through which animals happen to pass, many of them developing countries. A flyway fund that compensated corridor states for the global ecological service they provide would change the incentive structure.

Third, dispute resolution. When a state damages a shared maritime resource, other states can bring a case to the International Tribunal for the Law of the Sea. When a state destroys a migration corridor, no comparable forum exists. The absence of any adjudicatory mechanism means that even states willing to cooperate have no recourse against neighbors that defect.

These three elements, binding rules, financial transfers, and dispute resolution, are the basic architecture of any functioning governance regime. For migratory species, none of them exist at the international level. The CMS provides a platform for discussion. It does not provide governance.

The Clock and the Map

The governance deficit is not stable. It is widening. Climate change is redrawing migration maps faster than any diplomatic process can follow. Routes are shifting poleward. Timing is changing. Species are appearing in jurisdictions that have no legal framework for managing them and no institutional memory of their presence.

A bird that once migrated between two countries now crosses three. A marine species that stayed within one nation's Exclusive Economic Zone now enters another's. Each shift creates a new governance gap, a new jurisdictional boundary where protection ends and uncertainty begins.

The CMS COP15, meeting in Brazil in 2026, faces pressure to address these accumulating failures. The conference agenda includes discussions on ecological connectivity, transboundary corridor protection, and enhanced cooperation frameworks. Whether it can produce binding commitments, or only more resolutions, will test whether the international community has learned anything from the precedents of the sea, the sky, and the ice.

The godwit does not wait for treaties. Somewhere over the Pacific, B6 or one of its descendants is flying south again, burning through fat reserves accumulated on mudflats that may or may not still be there next year. The bird will cross no border that it recognizes. It will depend on every border it crosses. And the distance between those two facts remains the measure of a governance failure that the Westphalian order has yet to resolve.