During the prime migration months of August through November, hundreds of millions of birds fly over the United States each night. But how do they know what path to take? New research indicates that groups of birds “talk” to each other in the sky in order to decipher the path.
Scientists are gaining insight into mid-flight communication between groups of songbirds and resulting social associations. A team at the University of Illinois Urbana-Champaign captured over 18,000 hours of nocturnal bird call recordings to provide some insight into what important information is exchanged during these aerial chats.
In the daylight, birds are capable of recognizing natural landmarks and the positioning of the sun in order to orient themselves. In the dark, all visual cues are disconnected and birds are forced to rely on other tactics to make their long journeys. It has long been understood that many birds utilize magnetic fields as a guide and possess an inherent ability that works as an internal compass. However as Dr. Van Doren and his team at UIUC showed, another important mechanism may be at play.
The team captured acoustic recordings in 26 sites across the Northeastern United States from August to December, culminating in a total of 18,308 recorded hours. Using advanced artificial intelligence technology, 27 species of North American landbirds were identified by their calls. The team took this information and measured how frequently bird calls of distinct species overlapped with one another, indicating a back-and-forth line of communication between the birds.
“As climate shifts cause changes in migration patterns, communication between groups of migrating birds will become harder to maintain.”
If one species of bird called out and the other responded within a thirty-second window, then this was described as co-occurrence. It was reasoned that above a certain threshold co-occurrence events can be used as evidence for an existing social network.
Van Doren’s results show that 17 out of 27 species were found to “respond” to another distinct species’ calls frequently, suggesting active communication between species.
The study also tested co-occurrence within 15 second and 60 second windows to verify the existence of a social network. In these cases, 15 out of 27, and 20 out of 27 species were reported to communicate with another species during these windows respectively.
The results of this study indicate the existence of complex social networks between different species of migrating birds in the Northeast. While not believed to be the only method birds rely on for migration patterns, interspecies communication may contribute to the formulaic migration routes birds follow year after year.
As climate shifts cause changes in migration patterns, communication between groups of migrating birds will become harder to maintain. Birds will have to shift their timing to account for the delayed start of the seasons. As birds decrease in numbers, communication could become sporadic, adding yet another obstacle for the already endangered creatures.
We are just starting to explore the fascinating phenomenon of songbird communication, but it is clear that these feathered friends use teamwork to find their destinations. Perhaps humans can learn from the songbirds and work together to forge a path towards a brighter future.
