Bird Migration Patterns are Extremely Affected by Climate Change: Study
Sun, April 18, 2021

Bird Migration Patterns are Extremely Affected by Climate Change: Study

Birds migrate to find a more temperate habitat and to avoid acquiring diseases from other animals. / Photo by: Kranich17 via Pixabay


Birds, just like other species, are on the brink of extinction. The worsening of climate change has severely damaged their lives and habitats. Mass Audubon, the largest nature conservation nonprofit in Massachusetts, reported that more than 30 percent of Earth’s breeding birds are in decline. While most breeding birds will be affected by climate change, the most at risk are species that depend on high-elevation forest habitat, coastal breeders, and long-distance migrants.

It was reported that 49 percent of breeding forest species are highly vulnerable since their habitat will change markedly as the climate warms. These changes will cause increasingly fewer bird species associated with northern forests, including the yellow-rumped warbler and black-throated blue warbler. Also, 66 percent of breeding long-distance migrant species are highly or likely vulnerable since they are unable to adjust their migration schedules to coincide with the shifting peak abundance of their far-away food sources.

Unfortunately, bird migration patterns are also affected. Birds travel hundreds or thousands of miles between their breeding and non-breeding ranges for several reasons. For instance, they need to migrate to keep their food supplies from rapidly depleting, especially during the nesting season. During this season, food and breeding more complicated than usual. The competition for nesting sites is fierce, and predators hunt for birds more actively. 

Changing Winds Can Affect Bird Migration

Over the centuries, birds have evolved different migration patterns, destinations, and timing. This helps them take advantage of a wide variety of suitable conditions to raise their young, increasing their chances of a healthy offspring. They migrate to find a more temperate habitat, especially Arctic birds, and to avoid acquiring diseases from other animals. However, climate change is making migration more difficult for them.

A 2018 study conducted by researchers from Cornell University investigated how wind assistance would change, as it is critical for migratory birds. Science Daily, an American website that aggregates press releases about science, reported that it used data from over 143 weather radar stations to estimate the density, altitude, and direction birds took during spring and autumn migrations. 

Aside from that, the researchers used the 2018 report from the Intergovernmental Panel on Climate Change (IPCC), extracting wind data from 28 different climate change projections. The study published in the journal Global Change Biology revealed that changing winds may make it harder for North American birds to migrate southward in the autumn due to climate change. This is because winds from the south are projected to become stronger during spring and fall migration periods by the end of the century.

The good news is that birds would likely arrive in better condition on their northern breeding grounds with better odds of survival with stronger tailwinds during spring migration. However, their travel during fall migration into stronger headwinds would drain their energy. "The thing to remember about these projected wind changes is that they will not occur in isolation. There will be other global change factors for birds to contend with, including changes in temperatures, rainfall, and land cover,” lead author Frank La Sorte, a Cornell Lab of Ornithology scientist, said. 


Changing winds may make it harder for North American birds to migrate southward in the autumn due to climate change. / Photo by: alphaspirit via 123rf


Birds are Migrating Early

Climate change has another impact on migration bird patterns: they reach their summer breeding grounds on average about one day earlier. A 2018 study conducted by researchers from the University of Edinburgh analyzed hundreds of species across five continents. It also included species that travel with shorter migrations, like the lapwing and pied wagtail and those that travel huge distances, such as the swallow and pied flycatcher.

The Guardian, a British daily newspaper, reported that the researchers studied the records of migrating bird species dating back almost 300 years. They hope that this would help scientists better predict how different species will respond to environmental changes. The study published in the Journal of Animal Ecology and supported by the Natural Environment Research Council revealed that migrating birds are arriving at their breeding grounds earlier due to the increasing global temperatures.

It is important that birds reach their summer breeding grounds on time because it will affect seasonal temperatures and food availability. There’s a high possibility that they may miss out on vital resources such as food and nesting places, even if they arrive at the wrong time by only a few days. Long-distance migrants are also less responsive to rising temperatures. As a result, they may suffer most as other birds gain an advantage by arriving at breeding grounds ahead of them. 

“Many plant and animal species are altering the timing of activities associated with the start of spring, such as flowering and breeding,” Takuji Usui, of the university’s school of biological sciences, said.

According to Global Citizen, a movement of engaged citizens who are using their collective voice to end extreme poverty by 2030, a change in the birds’ arrival at their breeding grounds can endanger their mating habits and limit as well as shape their diet. This could disrupt a chain reaction of ecological patterns. 

Current and past studies about bird migration patterns prove that birds suffer more as the global temperature increases. While these animals are extremely resilient, there’s a high possibility that their way of living could change in drastic ways, leading to a tragic end.