IT’S REALLY HARD FOR BIRDS TO TALK OVER ALL THIS NOISE - Motherboard
A study released today in Bioacoustics found that birds residing in highly trafficked urban areas dynamically alter the way they sing in response to the noise from traffic. According to the researchers, this constant song shift in response to the noisy environment may affect the birds' ability to find a mate, in the same way that it might be hard for a human to find a mate if they went to a speed-dating function that was hosted at an active construction site. Ever tried yelling "HAVE ANY HOBBIES?" across a table at a total stranger? I'm no scientist, but I have a hunch it wouldn't work out too well.
However, according to some people at George Mason University who are scientists, it doesn't work out well for our avian friends, either. By recording the songs of Eastern wood pewees at three parks in and around Washington DC for a period of several weeks, the researchers found that the presence of motor vehicle traffic tended to result in songs with higher minimum frequencies of shorter duration. When traffic would drop off in these areas due to road closures, the frequency and duration would return to normal.
The singing adjustments made by the pewees likely improves the transmission of their message, whether to find a new mate or defend their territory, in a loud environment. However, they're not as effective in these tasks as they would be in a traffic-free environment and the birds on the receiving end of the song might not respond as strongly to the warning or pick-up line as they would otherwise.
This is particularly worrisome for the Eastern wood pewee whose numbers in the DC area have declined by over 50 percent since the 1940s. While traffic may not be the primary cause of this decline it's certainly not helping DC pewees and the researchers recommended temporary road closures as a way to remove some of the burden from the birds and lay the groundwork for an effective conservation strategy.
Then again, perhaps it's as Werner Herzog would have it and the birds are screaming in agony under the crushing weight of their own existence. In that case, traffic is the least of their problems.