Climate change is altering the rhythm of nature, particularly noticeably in the Arctic. Spring now begins much earlier there than it did just a few decades ago. For many migratory bird species that breed in high latitudes, this has far-reaching consequences. They must accelerate their migration more and more in order to reach their breeding grounds on time.
A Dutch–Danish research team has now discovered that this adaptation is becoming increasingly burdensome for many birds. In a study published in the journal Nature Climate Change and reported by phys.org, the researchers analyzed more than 500 documented spring migrations of five Arctic-breeding waterfowl species, including brent geese, barnacle geese, white-fronted geese, pink-footed geese, and tundra swans. The team combined extensive tracking data with long-term measurements of body weight taken in the birds’ wintering grounds.
The results paint a clear picture: To arrive earlier in the Arctic, the birds shorten both their feeding periods before departure and their stopovers during migration. This accelerated pace has so far allowed them to keep up with the increasingly early onset of spring, but the margin for adjustment is shrinking.
Scientists from the University of Amsterdam and the Netherlands Institute of Ecology warn that this strategy will only remain effective for a limited time. Analyses of climate trends and snowmelt data suggest that the birds can speed up their migration for only another 18 to 28 years. After that, even this maximum adjustment will no longer be enough to cope with changing environmental conditions. By the middle of the century at the latest, many species may be forced to find fundamentally new solutions, such as shifting their wintering grounds or completely altering their traditional migration routes.
Yet the birds’ ability to adapt is already reaching natural limits. Migrating faster means having less time to forage, but at stopover sites, access to high-quality food, favorable weather, and minimal disturbance is crucial to refuel enough energy. If these conditions are not met, the birds’ physical condition deteriorates. In the long term, this could lead to lower breeding success and declining populations.
The study makes one thing clear: Climate change is forcing even highly mobile species like migratory birds into increasingly risky adaptations. How long they can keep up with this pace remains uncertain, but what is certain is that their habitats and survival strategies will change dramatically in the coming decades.
Heiner Kubny, PolarJournal