One-fifth of migratory species listed by CMS are currently at risk according to a United Nations-backed assessment. This elevates concern across a wide range of wildlife and still aligns with the broader picture reported by international organizations working on biodiversity and conservation. The scope includes marine mammals, sharks, elephants, wild cats, predators, birds, insects, and other migratory groups. In total, 1,189 species are enshrined on the CMS roster, reflecting the diverse journeys these organisms undertake between habitats and seasons.
The assessment reveals that roughly 44 percent of the listed species have experienced population declines in recent years. Of particular alarm is the status of migratory fish—nearly all of them, about 97 percent, face extinction risk within their migratory corridors. This highlights the vulnerability of fish populations that rely on intact migration routes for spawning and feeding, routes that are increasingly disrupted by human activity.
As the first comprehensive appraisal of migratory species and their adaptive challenges in a world transformed by human actions, the report identifies two dominant threats: overexploitation and habitat loss. Expanding agricultural land, new roads, and other infrastructure fragment the landscapes these species traverse, sometimes breaking critical migration paths and complicating or preventing their seasonal movements. These disruptions can cascade through ecosystems, affecting breeding success, food availability, and long-term survival.
About 58 percent of the areas designated as important for migratory species are now altered by human activity. This encroachment underscores the need for landscape-scale conservation planning that recognizes migratory routes as corridors rather than isolated habitats. Maintaining connectivity helps species complete their journeys and reduces the likelihood of local extinctions in key stopover sites and breeding grounds.
Climate change and pollution compound these pressures. Shifts in temperature and weather patterns push some species to relocate farther than usual, while others adjust their timing, arriving before or after peak food resources or mating opportunities. When a species emerges out of sync with its ecosystem, it can struggle to find adequate nourishment or a partner to reproduce with, jeopardizing population stability and genetic diversity over time.
A striking example is the narwhal, known for the distinctive spiral tusk. These Arctic representatives typically spend summers in ice-free coastal waters before moving toward deeper Arctic seas for the winter. As ocean temperatures rise and sea ice dynamics shift, some narwhals are delaying their migrations. The resulting lag can leave them stranded in changing ice conditions or cut off from essential feeding grounds, increasing the risk of harm during seasonal transitions and complicating their annual life cycle.
Researchers have noted that changing solar, atmospheric, and oceanic conditions can influence migratory patterns in birds as well. While previous studies explored how solar activity could affect flight timing and navigation, current observations emphasize the broader impact of environmental variability on migratory behavior and success. These findings reinforce the view that migratory species are highly sensitive indicators of ecosystem health and climate change, reflecting broader ecological shifts that require coordinated, cross-border responses across habitats and governance regimes.
In summary, the CMS assessment offers a comprehensive snapshot of migratory species under pressure, highlighting both the universal threats faced and the region-specific challenges that emerge from altered landscapes and climates. The report calls for enhanced protections, sustainable land-use planning, and stronger cooperation to preserve critical migration corridors, safeguard biodiversity, and sustain the ecological services these species provide to ecosystems and human communities alike.