Migratory birds sing to unite with other species

Migratory birds sing to unite with other species

Written by Lee Ga Young Edited by Sarah Lewin Frazier

Small songbirds such as cardinals and warblers travel thousands of miles, flying at night and resting during the day, traveling to and from their wintering grounds. And unlike many larger birds, they avoid flocks and travel separately. But new research suggests they’re not completely alone in the dark skies. Benjamin Van Doren, an ornithologist at the University of Illinois at Urbana-Champaign, and colleagues set up ground-based microphones at 26 locations across eastern North America and collected more than 18,300 hours of bird calls in flight. Researchers suggest that solitary migrating songbirds may cooperate across species, sharing information with other solo travelers about who they are and what to look out for in the future. I discovered that there is a sex.

The findings of the study were announced on Wednesday. current biologythere is growing evidence that social interactions between species can influence songbird migratory behavior more than previously thought.

Conventional wisdom has been that “each bird follows its own inner instincts and experiences,” Van Doren said. “If they are not young and have already experienced several (migrations), they definitely rely on memory and experience, but they are usually solitary.”

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Flying in the dark poses challenges for airlift cooperation, said Alison Pierce, a biologist at the University of Colorado Denver who studies plover migration and was not involved in the new paper. For example, there are no visual cues, such as another bird’s flight path. This forced Van Doren and his colleagues to look for, or rather listen to, other data. It’s a seemingly random sound that songbirds make every few seconds to a minute.

“It’s really unclear why they’re spending so much energy and effort making phone calls during migration,” Van Doren said. “There has to be some reason or benefit to this action. Otherwise, it’s just a waste of energy.”

To analyze what ended up being a huge amount of data, Van Doren and his colleagues used machine learning technology with a customized version of Merlin, a bird call identification app developed by the Cornell Lab of Ornithology. did.

The researchers found that individual birds of different species fly close to each other and call to each other in specific patterns. This is “more than can be explained by chance,” Van Doren said. So there seems to be some reason why the bird was nearby. The new study “potentially suggests that these birds are not trying to find their way from Chicago to Argentina entirely on their own…and perhaps indeed these birds that migrate at night… It’s possible that some social information is being exchanged among billions of songbirds, and it’s entirely possible that this will overturn our understanding of how songbird migration works. please. ”

Van Doren said it’s still unclear exactly what information the birds are communicating. But researchers have pretty accurate guesses. For example, different types of birds make different calls, but even within the same species, the “calls” differ depending on age and gender groups. This suggests that birds may use such information to introduce themselves. Either way, “by staying in touch with others, you’re likely to be able to act more effectively,” Van Doren explains. For example, they may be exchanging knowledge about landing sites or difficult weather conditions such as fog or rain. “Migration is a very dangerous time, even for birds that have migrated before.”

Van Doren added that he had previously observed that songbirds form “mixed species flocks” while foraging during the day and avoiding natural predators. New research suggests such partnerships may play a more important role than researchers realized. Additional studies will further test these hypotheses, preferably using more direct tracking methods, such as tagging specific birds and tracking them as they migrate.

“If we can get data from this large population scale and understand what these individuals are doing, that’s key to understanding how birds move,” Pearce said. says.

“To me, it speaks to the amazing complexity of how nature works,” Van Doren says. “And it’s exciting that we’re still learning new things about these well-known phenomena that are just spectacular.”