The rising global temperature is having some strange effects on the migratory patterns of birds around the world.
A flock of redwing blackbirds in Kansas. Jerry Segraves. CC0
Warming temperatures, glacial melts, ocean acidification and dozens of other crises are all clamoring for the attention of the global public. Although many are already exhausted by the near-constant onslaught of bad news, there’s still one more factor to add to the pile.
An astonishingly high number of bird species are annual or semiannual migrators, heading from cold to warm weather to follow their insect prey during fall and winter. While far from the only animal to migrate, birds are perhaps the most famous ever to do it. Now, scientists are discovering the ways in which climate change has even managed to wreak havoc on their yearly vacations.
Although birds migrate annually, their departure and arrival times vary based on weather conditions. Their exodus does not follow an arbitrary determination of season but simply begins when the weather turns cold. Scientists have argued that rising global temperatures are causing spring to arrive earlier in the year. This change has a few effects on the more transitive part of the world’s bird populations.
Studies conducted on 90-year-old data have suggested that birds are now leaving later in the year, as warm weather lingers well into the fall. This means that birds frequently arrive too late for peak insect season, missing out on the food they have come to rely on for the winter. This also disrupts their egg-laying patterns, resulting in birds breeding further north and gradually shifting the population.
Other migratory birds have been traveling far from their typical homes, with some traditionally “tropical” birds appearing much further north than they have ever been documented. Between this location shift and delayed egg-laying, scientists have suggested that migratory changes could cause many bird species to run out of land to migrate to in the next few decades.
More recent studies have shown a rising variance in departure times compared to 23 years ago. Researchers attribute the abnormality on the East Coast to substantial atmospheric disturbances called Rossby waves, which shift warm air from tropical areas up north to the poles while returning cold air down towards the equator. As temperature changes occur worldwide, these waves have become weaker over time as the poles warm.
Other scientists have suggested a connection between the recent increase in severe weather events and migration disruption. In 2023, a pair of flamingos was spotted in a small Ohio town after being blown off-course by a hurricane. These birds typically travel from Cuba to the Yucatan Peninsula, but after being swept up in the storm, around 150 were documented across the southern United States. Similar natural disasters disrupting migratory patterns have cropped up in recent months as what experts have called “the worst hurricane season on record” kicks into high gear.
Birds are one of the most iconic and beautiful animals in the world, and their annual migrations are seen as a symbol of seasonal change and the arrival of autumn. However, with the climate in crisis, even a seemingly consistent rule of nature is thrown into turmoil. In the next few decades, some scientists have hypothesized that birds might run out of room and simply stop migrating altogether.
Ryan Livingston
Ryan is a senior at The College of New Jersey, majoring in English and minoring in marketing. Since a young age, Ryan has been passionate about human rights and environmental action and uses his writing to educate wherever he can. He hopes to pursue a career in professional writing and spread his message even further.
