Every other Friday, NHPR’s Outside/In team answers a question from a listener about the natural world. The latest one comes from a follower on Instagram, who asks: “How do birds, whales, and other migratory animals communicate to younger generations about how/where to migrate?”
Although we’ve come to learn a lot about how animals behave and socialize, there’s still a lot researchers don’t understand about how animals transfer skills and knowledge across generations – especially when it comes to migration.
For one, social and communication behaviors vary across the numerous species that migrate, including fish, crustaceans, mammals, amphibians, reptiles and insects.
Plus, migration journeys are long.
“It’s a logistical problem to be able to follow these animals,” said Patrik Byholm, a lecturer at the Novia University of Applied Sciences in Finland who specializes in bird research. “I mean, we are talking about often at least huge distances thousands and thousands of kilometers that they or miles that they migrate together.”
That being said, there are animals that don’t explicitly communicate with each other — or to their young — about how to embark on their migration journeys. Some simply know where to go instinctually. Cuckoos, for example, lay eggs in other birds’ nests, meaning they never interact with their young, which have to make the migration journey on their own. Monarch butterflies travel westward across the U.S. and south to Mexico, with the sun as their navigational guide. There’s also evidence that monarch butterflies have an “inclination magnetic compass” that helps them fly in the right direction.
Teaching behavior
Byholm and his team of scientists are making headway in better understanding how certain bird species behave when they do migrate. They published a paper last year about caspian terns – which the Cornell Lab of Ornithology describes as being famous for their “red fish-knife of a bill and deep, raspy call.”
After following groups of the birds using GPS trackers from Finland to Africa, they made an interesting discovery: It was the male parents that showed the young “the secrets of migration,” as Byholm put it.
“The young followed their male parent, and he showed them where to rest and where to feed,” he said.
Meanwhile, he said, the female parent typically migrated to a different destination in the winter.
Byholm said their findings suggest the migration journey with the male parent is critical for the young’s chances of survival. Young terns that didn’t follow or lost contact with the adult male while migrating had a higher mortality rate than the ones that did. And, those early life experiences leave a lasting impact on the birds’ decision-making processes: For the most part, the young birds that successfully made the journey used the same stopover sites from that first trip in future migrations.
As Byholm conducts more studies on bird migration behavior, he said the research process is a nice reminder of how there’s so much more to learn and discover about animals.
“As it often is with us scientists, or perhaps people in general, we believe we know we know something,” he said, “but then when we actually start digging into these questions, you realize how little you know.”
If you’d like to submit a question to the Outside/In team, you can record it as a voice memo on your smartphone and send it to outsidein@nhpr.org or call the hotline, 1-844-GO-OTTER.
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