Male bluebirds alter songs to be heard over increased acoustic noise

http://www.eurekalert.org/pub_releases/2015-08/uoe-pas081915.php

Public Release: 21-Aug-2015
Persist and shout: Male bluebirds alter songs to be heard over increased acoustic noise
UK and US research shows birds 'shout' to be heard over the noise produced by man-made activity
University of Exeter

Birds 'shout' to be heard over the noise produced by man-made activity, new research has shown.

The innovative study, led by an expert from the University of Exeter, looked at how bluebirds altered their songs in response to increases in nearby background noise caused, in many cases, by human activities such as traffic.

It found that the birds altered their songs immediately after noise levels intensified, making 'real-time' adjustments in order to produce songs that are both louder and lower-pitched. The results suggest that birds are able to perceive increases in noise and respond accordingly - not unlike humans do when in raucous settings.

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Dr Swaddle said: "Unfortunately, the world is getting so noisy that even the most flexible of species will eventually reach a threshold beyond which they will have difficulty communicating--which will impact their ability to breed successfully. When we build roads and airports near human neighbourhoods, we employ noise abatement protocols in an effort to mitigate against the negative impacts of noise pollution. It is time to apply similar caution to conservation, management, and landscaping plans that impact wildlife and their habitats."