Rooftop wiretap aims to learn what crows gossip about at dusk

Date:  December 5, 2017

Source:  University of Washington

Summary:

An interdisciplinary team is using a covert sound-based approach, worthy of an avian CSI, to study the link between crows' calls and their behavior.

What are crows saying when their loud cawing fills a dark winter's evening? Despite the inescapable ruckus, nobody knows for sure. Birds congregate daily before and after sleep, and they make some noise, but what might be happening in those brains is a mystery.

Curious about these raucous exchanges, researchers at the University of Washington Bothell are listening in. They are placing equipment on the roof of their building -- a meeting place for some of the thousands of crows that sleep in nearby campus trees -- and using a sort of computerized eavesdropping to study the relationship between calls and the birds' behavior.

"With audio alone, our team is able to localize and record the birds remotely, and in dim light that makes this situation less suitable for video tracking," said Shima Abadi, an assistant professor at UW Bothell's School of Science, Technology, Engineering & 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."

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Common Swifts Make Mysterious Twilight Ascents

Feb. 21, 2013 — Common swifts climb to altitudes of up to 2.5 km both at dawn and dusk. This unexpected behaviour was discovered by geo-ecologist Dr Adriaan Dokter of the University of Amsterdam's (UvA) Institute for Biodiversity and Ecosystem Dynamics (IBED) together with colleagues from the Royal Netherlands Meteorological Institute (KNMI), the Royal Netherlands Air Force and Lund University.

The research results were published as a featured article in the March issue of the scientific journal Animal Behaviour.

In the summer, swifts make their presence felt in the city, especially because of the screaming sound they make. These common urban birds appear to have unusual movement patterns. Besides a short breeding period under urban roofing tiles, these birds spend all year on the wing: foraging, mating and even sleeping are all performed in flight. Using a novel radar technique, Dokter and his colleagues studied the nocturnal flight behaviour of the common swift with the assistance of a weather radar belonging to the KNMI.

Dokter explains: 'We always assumed that common swifts ascended in the evening as part of their sleeping cycle. However, now that we have observed the bird perform ascents at both the start and the end of night-time periods, this interpretation seems to be incorrect. The ascents must have a different function, with the birds making use of the unique opportunities offered by the twilight period.'

Read on:  http://www.sciencedaily.com/releases/2013/02/130221084709.htm