Migratory Species of Panama: Shorebirds, Whales, and the CMS Flyway

A country built for migration

Migration is the defining ecological fact of Panama’s wildlife, and the reason is pure geography. The country is a narrow isthmus, at points less than 60 km wide, sandwiched between two continents and two oceans. Any animal that moves on a continental or oceanic scale is liable to pass through or over it, which makes Panama a natural bottleneck. Bottlenecks concentrate migrants, and concentrated migrants are both an ecological spectacle and a conservation responsibility, because a threat at a bottleneck endangers an entire migratory population, not just a local one.

The migrants come in several distinct streams, each using a different part of the country. Shorebirds move along the Pacific coast, resting and feeding on the mudflats. Humpback whales arrive in Pacific waters to calve. Sea turtles nest on both coasts and migrate across the eastern tropical Pacific. Large pelagic sharks range through the same open-ocean corridors. Understanding Panama’s migratory species means following each of these streams, because they are governed by different biology, different threats, and different international agreements.

The shorebird story: Bahía de Panamá and the western sandpiper

The best-documented migratory phenomenon in Panama is the shorebird concentration on the upper Bay of Panama, the same stretch of coast that carries the Bahía de Panamá Ramsar designation (see wetlands-and-ramsar). The bay’s tidal mudflats are a fueling stop on the Pacific Americas shorebird flyway, the great north-south route along which sandpipers, plovers, and their relatives move between Arctic breeding grounds and South American wintering grounds.

The flagship species for this story is the western sandpiper (Calidris mauri), a small shorebird rated Least Concern on the IUCN Red List, with an estimated 3,500,000 mature individuals, by the IUCN Red List Authority for birds^[4]. Its significance for Panama is the share of that population that passes through the upper Bay of Panama during migration: a substantial fraction, on the order of 14% of the global western sandpiper population, uses these flats^[3][2]. That is the number that earns the bay its international wetland status: when a single site holds double-digit percentages of a species’ world population, even briefly, it is objectively important at a global scale.

The conservation implication is the bottleneck point again. If the mudflats of the upper Bay of Panama were degraded (by reclamation, pollution, or the coastal development pressure that comes with sitting on the edge of a million-person city), the effect would not be local. It would hit a migratory population that depends on that specific stopover to complete its annual cycle. That is why a shorebird mudflat next to a capital city is treated as an issue of international, not municipal, concern.

The CMS framework and COP15

Migratory species cross borders, which means no single country can protect them alone, which is why the Convention on the Conservation of Migratory Species of Wild Animals (CMS) exists. CMS is the international treaty under which range states coordinate protection for animals whose life cycles span multiple jurisdictions, and its periodic Conference of the Parties (COP) is where the binding decisions get made.

The most recent relevant CMS action is from COP15, held in Brazil in March 2026, where BirdLife International reports major breakthroughs for migratory birds, most notably a new marine flyway framework agreed by the delegates, alongside stronger protections for seabirds, raptors, and shorebirds^[1]. A “flyway” is the full geographic pathway a population uses across its annual cycle (breeding, migration, wintering), and protecting one means coordinating conservation across every country along the route rather than site by site. The new marine flyway framework is significant because it extends that coordinated approach into the ocean, where migratory seabirds and the marine species they overlap with have historically been harder to protect than terrestrial migrants.

For Panama, the CMS framework matters directly. The country’s shorebirds, its nesting sea turtles, and the pelagics in its expanded marine protected areas are all CMS-relevant species whose protection depends on what happens in other range states as much as on what happens inside Panama. International agreements like the COP15 marine flyway are the mechanism that turns a single country’s protected areas into a connected pathway.

The marine migrants

The marine side of Panama’s migration story runs in parallel to the shorebirds and is covered in detail on its own pages. Humpback whales, both Northern and Southern Hemisphere populations, use Pacific waters, including the Gulf of Chiriquí, as wintering and calving grounds (see humpback-whales). Sea turtles nest on both coasts and migrate across the broader eastern tropical Pacific (see sea-turtles-panama). And the large pelagic sharks protected by the Banco Volcán expansion (scalloped hammerhead, oceanic whitetip, and others) are themselves wide-ranging migrants whose conservation depends on the marine-corridor network (see shark-conservation and marine-protected-areas).

What unites these marine migrants with the shorebirds is the corridor logic. None of them can be protected by a single park, because none of them stay inside a single park. The Eastern Tropical Pacific Marine Corridor (CMAR), the CMS marine flyway framework, and the Ramsar shorebird designations are all expressions of the same insight: for a migrant, protection has to follow the route.

Why this is a Panama story specifically

The reason a page on migratory species belongs in a Panama guide, rather than being left to a general wildlife reference, is that the isthmus gives the country an unusually concentrated migratory experience. A traveller in Panama at the right season can see hemispheric-scale shorebird concentrations within sight of the capital’s skyline, watch humpback whales from the Pacific coast, walk sea-turtle nesting beaches, and dive with migratory pelagics, all inside a country small enough to be crossed in a day. Few places compress that much migratory biology into that little distance.

Where to follow Panama’s migrants

If your interest is birds, the upper Bay of Panama at migration season is one of the great shorebird spectacles of the Americas, and the birds-of-panama and birdwatching-guide pages are the practical next step. If your interest is marine life, the whale-, turtle-, and shark-focused pages cover the migrants you are most likely to encounter. And if you are interested in conservation, the recurring lesson of Panama’s migratory species is that protecting them is inherently international, which is why the Ramsar wetlands, the CMS flyway agreements, and the marine corridors all matter, and why a threat at a single bottleneck like the Bay of Panama is treated as a problem for an entire flyway.

What a flyway is, and why it changes conservation

The flyway concept is the organising idea behind modern migratory-species protection, and it is worth understanding because it reframes what “protection” means for a migrant. A flyway is the full geographic pathway a migratory population uses across its annual cycle, the breeding grounds, the wintering grounds, and every stopover in between. For a shorebird on the Pacific Americas flyway, that pathway can stretch from Arctic tundra to Patagonian estuary, crossing a dozen countries. Protecting such a species by protecting a single site, even a Ramsar-class site like the Bay of Panama, is necessary but not sufficient, because a threat at any other point on the route can collapse the population just as effectively as a threat at the most important stopover.

That is why the 2026 CMS COP15 marine-flyway agreement matters. It represents the range states along a pathway coordinating protection across borders, so that a species is conserved along its whole route rather than only inside the jurisdictions that happen to host its best-known sites. For Panama, which sits on multiple flyways, the value of that coordination is direct: the country can protect its shorebird mudflats, its whale calving grounds, and its shark populations as well as any single state can, but the migrants that use them also depend on what happens in Costa Rica, Colombia, Ecuador, the United States, and Canada. Flyway-scale agreements are the mechanism that makes that interdependence operational rather than aspirational.

Why a bottleneck is a single point of failure

The concentration that makes Panama’s migratory spectacles so striking is also what makes them so vulnerable, and the concept of a bottleneck captures the risk precisely. A bottleneck is a geographic pinch-point through which a large share of a migratory population must pass, a narrow isthmus, a specific bay, a particular mountain gap. The upper Bay of Panama is a bottleneck because a substantial fraction of the global western sandpiper population funnels through its mudflats each migration. That concentration is what makes the bay a spectacle and what earns it international designation, but it also means that a threat at the bottleneck endangers a disproportionate share of the entire population, not just the local birds.

The arithmetic is unforgiving. If a disease, a reclamation project, or a pollution event degraded the Bay of Panama mudflats badly enough to close them as a stopover, the effect would not be confined to the birds that happened to be there that season. It would hit the migratory population that depends on that specific refuelling site, across its whole range. That is the conservation logic behind the international attention paid to what looks, locally, like a stretch of mud on the edge of a city: a bottleneck is a single point of failure for a hemispheric migration, and protecting it is protecting far more than the ground it occupies. The same bottleneck logic applies to Panama’s whale and turtle sites, which is why flyway-scale thinking, rather than site-by-site protection, is the frame that matches how migratory species actually live.

What else COP15 covered: seabirds and raptors

The 2026 CMS COP15 breakthroughs relevant to Panama extend beyond the marine flyway. BirdLife International reports that the conference strengthened protections for seabirds and raptors alongside shorebirds, not only the headline marine framework^[1]. Raptors are a CMS concern that maps directly onto Panama’s bottleneck geography: the same narrow isthmus that funnels shorebirds along the Pacific coast also concentrates diurnal raptor migration as the birds move between continents, so stronger range-state coordination for raptors is a matter of direct relevance to a country that sits under a concentrated migration route. Seabirds, meanwhile, map onto the Pacific marine protected areas. The Banco Volcán and Cordillera de Coiba zones overlap the open-ocean ranges of migratory seabirds whose protection has historically lagged behind that of land migrants, because no single state controls the waters they use.

The practical point is that the COP15 package, read as a whole, gives Panama coordinated international protection across the three migratory-bird streams its geography funnels: shorebirds on the coastal flats, raptors over the isthmus, and seabirds over the expanded marine reserves. Each stream has historically been handled through a different instrument (Ramsar for the shorebird flats, range-state agreements for the raptors, marine protected areas for the seabirds), and the value of a broad CMS decision is that it raises the coordination floor for all three at once rather than leaving each to its own fragmented regime^[1].

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Last reviewed: 2026-07-03