Migration is a common phenomenon in the animal kingdom where a group moves from one place to another. Usually, it searches for a suitable living condition. This had been observed with different species, including humans, but one of the most observed migration is among birds.
As observed by ornithologists and biologists, migratory birds often make extreme journeys. According to the Cornell Lab of Ornithology, birds migrate from areas with decreasing resources towards areas that are abundant with food and possible nesting locations.
Scientists widely record bird migrations, but it seems there is still a lack of understanding on our part on how they can travel these distances and how the threat of climate change means for these migration patterns.
THE THREAT OF CLIMATE CHANGE
The rapid change in global temperature causes the planet's seasons to be volatile, and this can affect the breeding patterns of birds. According to Professor Stuart Bearhop, an expert on animal ecology from the University of Exeter in the United Kingdom claims that there is evidence retrieved from bird populations that climate change is probably going to affect the demography of the species.
Professor Bearhop and his team in the STATEMIG project studied the migration of the Brent geese, which travels from Ireland to the Arctic, where they breed. They found out that the changing climate is indeed affecting the population of Brent geese. In their study "Fitness drivers in long-distance migrants: the interacting roles of physiology, social biology, ecological and physical environments", Professor Bearhop explained: "Wet years are predicted to increase with climate change as temperature rises, but, of course, because they travel so far north, it doesn't mean rain, it means snow."
In the case of Brent geese, the species breeds in cold weather, but if there is rampant snow, there will be few places for them to raise and feed their offspring. Professor Bearhop and his team were able to observe that the colder climate causes the breeding season to occur later in the year, affecting their populations.
The team chose the species for their study in migration because of their routine migration, and the offspring still rely on their parents for at least a year. These patterns are useful for the team because they provide insights into the population levels and determine what could be directly affecting their migration. The birds are observed by the researchers in Ireland and Iceland, where they were able to attach tags before the birds migrated to the Arctic region for their breeding season.
The birds eventually returned to Ireland with their offspring, and it is only until then that the researchers were able to compare the population levels and figure out the changes and the environmental factors that could have caused these changes in their journey.
ANOTHER PERSPECTIVE
Decades worth of studies in bird migration made ornithologists understand why the phenomenon exists, where the birds go when they migrate. Still, those studies fell short in making scientists understand what is actually happening. According to Dr. Sissel Sjoberg of Bird Migration Research from the University of Copenhagen in Denmark, this is because there are no tools to understand birds during migration accurately. High-resolution tags are not available for birds of all sizes, especially for small birds.
The tags also fail to provide details like altitude or how the birds are able to traverse inhospitable areas. Because of these reasons, Dr. Sjoberg and her team launched the BIRDBARRIER project. The project aims to put sensors on the backs of small, nocturnal birds migrating long distances which are encased in tiny 'backpacks'
These backpacks are complete with an activity log and a pressure sensor which will determine the height and the behavior of the bird every 5 minutes of the journey. In the study 'The Importance of Barriers in Bird Migration,' Dr. Sjoberg explains that scientists previously thought the small nocturnal birds are limited to flying at 2,000 - 3,000 meters above sea level only but the team was able to observe the same birds fly as high as 6,000 meters above sea level.
