At the meeting, Slabbekoorn will present data for a new species able to shift the frequency of its birdsong upward to adapt to urban noise: the chiffchaff (Phylloscopus collybita), recorded along a highway in the Netherlands. "The field data reveal for the first time that this species is able to adjust immediately to exposure to highway noise via artificial playback in quiet territories," he says. "Acoustic flexibility may be key to efficient use of the 'left-over acoustic space,' and may determine whether individual birds can maintain their territory and breed successfully." At risk are those species of bird unable to adapt their songs in response to increased traffic noise by shifting frequencies, reducing their chances of mating successfully; these populations may be declining in urban areas because of the interference in communication.
Paper 1pAB4, "Acoustics flexibility in singing birds under noisy urban conditions." will be presented at 2:00 p.m. on Monday, June 30 in room 342B.
3) HYENA GIGGLES AND GROANS.
A hyena's laugh might be less telling than its groan, according to researchers at the University of California, Berkeley, who have studied the acoustic properties of various vocalizations of the spotted hyena (Crocuta crocuta), also known as the "laughing hyena." The laugh - dubbed a "giggle" by those who study the animal - is a vocalization used more frequently in competitive situations, such as haggling over prey, while loud whooping calls are used for long-distance communication. However, groans are the most common type of vocalization for communicating in short-range settings among this highly social species. Types of groans vary from a growling noise to more tonal sounds, according to UCB's Frederic Theunissen (
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American Institute of Physics