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Press releases | Research | Science
December 5, 2017
The University of Washington Bothell is home to a tower of about 15,000 crows that sleep in nearby wetlands during the fall, winter and winter. spring. University of Washington
What do the crows say when their loud cackling fills a dark winter night? Despite the inescapable uproar, no one knows for sure. Birds congregate daily before and after sleep, and they make a little noise, but what might be happening in those brains is a mystery.
Curious about these noisy exchanges, researchers at the University of Washington Bothell are listening. They are placing equipment on the roof of their building – a meeting place for some of the thousands of crows that sleep in the nearby trees of the campus – and using a kind of computerized eavesdropping to study the relationship between calls and the behavior of birds .
The biologist Douglas Wacker and the acoustic expert Shima Abadi lead an interdisciplinary team of undergraduate student researchers. University of Washington
"With audio alone, our team can locate and register birds remotely and in conditions of light that makes this situation less suitable for tracking videos," said Shima Abadi, badistant professor at the UW Bothell School of Science, Technology and Engineering. ng and Mathematics. "It's still a challenging task, but we can use the audio signals to look for patterns and learn more about what the birds may be communicating."
Abadi's background is the acoustics of the ocean; some of his previous research tracked the whales using underwater microphones in the ocean. For this project he partnered with a colleague in biology who studies the local crow population with his undergraduate students.
"They are incredibly strident, and they make this cacophony every night, and people ask themselves: What are they saying? And that's a big question on this campus," said Douglas Wacker, badistant professor of biology at UW Bothell.
Wacker earned his doctorate at the UW studying song sparrows. After joining UW Bothell in 2012, it was natural to study the approximately 15,000 crows that migrate to North Creek Wetlands on campus every afternoon in fall, winter and spring.
People who walk around the campus can not stop listening to the not always melodious sound of birds.
"Crows make a variety of different calls, some of which we understand functions quite well, and others not so well," Wacker said. "Your normal calls are not necessarily well understood, we do not know what information they might be broadcasting."
He and Abadi have nearby offices. Last year they decided to collaborate on an interdisciplinary project that combines their experience in biology with their experience in acoustics.
Although the field site on the roof of the building of faculty members is convenient, this project poses technical challenges. These crows call in a noisy environment, where it is difficult to separate their vocalizations from different birds and other surrounding sounds. Also, crows are smart. They will change their behavior if they believe humans are watching, or even if there are unknown teams nearby.
That's why you need a high-tech approach, worthy of an avian CSI.
The study on the rooftop of the UW Science Building Bothell has audio recorders located on four corners of a 10-foot square. The birds get used to the equipment and then they can be observed when they meet as usual at sunset. University of Washington Bothell
The team of mostly undergraduate students has been perfecting their audio recording technique. They placed four audio recorders in a 10-foot square in a parking lot, and then placed a speaker by touching a crow in one of the quadrants. The recorders have precise time stamps to calculate when the sound waves arrive, and then the software compares the hours to determine where the sound was generated.
Students discovered a way to focus on the highest quality audio to triple the accuracy of source locations. Now you can use the recordings to locate the origin of the call between 6-12 inches, or about the size of a bird.
Birds gather on the roof before perching on nearby trees to sleep. University of Washington
About 50 to 100 crows could gather at the pre-roost meeting at sunset on the roof of the science building. Its incessant squawk during the flight is silenced and an occasional burst occurs on the roof. With the help of Abadi, the team is working to develop a user interface and computer techniques that select particular calls, so that they do not have to manually choose hours of squawking, but can focus on the most interesting events.
Derek Flett, an undergraduate student in mechanical engineering, will describe the team's efforts on December 5 at the annual meeting of the Acoustic Society of America in New Orleans.
This winter, the researchers plan to use the equipment in nature, that is, on the roof, to monitor real groups of crows. Finally, they hope to combine audio surveillance with video, so they can study how birds can react to particular sounds.
They have also begun to test their theories by making private calls and then seeing if the crows react in the intended manner.
Crows gather at the UW Bothell sports field before sleeping in the nearby wetlands. University of Washington
The idea that calls contain meaning is plausible, Wacker said. The number of squawks, or the length of squawk pauses, could say something about the sources of food or possible dangers.
"If a bee can dance to tell other bees where the food is, then undoubtedly a very intelligent bird – in a family with other species of birds that are able to learn to understand, recognize themselves in a mirror, recognize Faces and transmitting that information to later generations could be able to communicate complex information, "said Wacker.
The other co-author of the paper presented in December is Virdie Guy, a mechanical engineering student. The research is funded by a Royal Research Fund of the University of Washington.
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For more information, contact Wacker at [email protected] and 425-352-3723 or Abadi at [email protected] or 425-352 -3835. More photos are available to download here.
Label (s): biology • birds • Douglas Wacker • Shima Abadi • UW Bothell
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