The Sound of Evolution

[Image: Istanbul Birds in Flight by Tim O'Brien].

City birds have begun to sing new songs. "Gone is the familiar dawn chorus, with its rich mix of enchanting melodies and calls," New Scientist writes. "In its place is a strangely depleted music – abrupt, high-pitched and sometimes ear-piercing."
It seems that constant background sound in cities is having an alarming effect on bird species.
    Some species simply are not able to make themselves heard above the ever-growing racket and are finding themselves squeezed out of the city. Others are beginning to change the way they communicate. In the long term, new species may evolve. If noise levels continue to rise, it seems inevitable that urban bird life will change dramatically.
Birds such as house finches, blackbirds, and – yes – great tits are learning how to adapt.
Researchers found that great tits in the city, for instance, will actually sing "higher-pitched tunes than their forest-dwelling counterpart" – indeed, that city tits even tune in to different noises now because they're drowned out at other frequencies.

[Image: Bird subcommittee on traffic by Rosanne Haaland].

This, too, could have huge implications.
    If singing and hearing diverge enough, urban birds may be less likely to find the vocals of rural birds attractive, or even to recognise them as members of the same species. These changes could serve to eventually split populations into genetically distinct urban and rural species. Alternatively, different populations of the same species might adopt differing strategies to cope with urban noise, leading eventually to a species split occurring in birds living in the same neighbourhood.
Roads and other forms of transport infrastructure – such as airports – are a major part of the problem. In Holland, we read, "the construction of a road near a particular [warbler nest] reduced the number of warbler breeding pairs from around 10 to just two. When the road was closed for repairs for two years, five more pairs moved into the area, although the subsequent return of traffic drove them away again."
Everyone, and everything, is just looking for some peace and quiet.
I'm reminded of something I've written for a future issue of Dwell about the role of urban sound control in massive eco-design schemes – but I'll leave that unexplored till the (albeit very brief) article comes out.

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6 Comments:

Anonymous Anonymous said...

How very sad. I was thinking about this very thing a while ago while walking the streets of central London, listening to a bird belting out its song.

April 01, 2008 2:59 PM  
Anonymous Anonymous said...

Truly lamentable, to lose any pair of great tits amidst the cacophony of the urban jungle.

April 01, 2008 7:47 PM  
Blogger Michael said...

Reminds me of an article in the NYT recently about White Nose Syndrome killing bats. Apparently it's a viral disease of some sort causing white noses then death. But when I first read it, I thought it was WHITE NOISE SYNDROME. Bats dying from the ambient urban drone, etc. Just a thought.

April 02, 2008 2:48 PM  
Blogger KimiK Gibson said...

I somehow doubt that the noise pollution is simply a problem for birds, insects and forest dwelling mammals. I have read articles that have studied the impact of growing up in an urban region where children are exposed to constant sound pollution from airports, roads, or other urban entrails, construction perhaps - and it's not looking good for humanity either. Children in these areas were more prone to persistent stress which impacted chemicals like melatonin levels, sleep patterns, stress and anxiety - all of which were detrimental to the child's learning ability, hearing and plausibly other factors.
Something to ponder about where we live and where we should be willing to live.

April 03, 2008 5:22 AM  
Blogger J E Carter II said...

I noticed a Robin emitting a shrill piercing, single note the other day in the park near a construction project that has been going on since last year. It was a sound I'd not heard a Robin make before - they are often cheerful sounding, especially out in the country where I live. The angry sound of a Mother Robin protecting her nest not nearly as piercing and monochromatic as the sound this city bird made. Makes me wonder if that solitary note is simply a song I'd never heard or an adaptation.

April 04, 2008 7:09 PM  
Anonymous Rombsy said...

And it's not just noise pollution... Light pollution in cities is having a big effect on birds. Street lights confuse many species that it is dawn, all night long. They sing their dawn songs all night rather than resting, which leaves them with less energy for mating, nesting, breeding, rearing their young, etc. The following sites detail some of the other nasty complications for birds and other species.

National Geographic

Light Pollution

Calgary

...and what one city in Canada is doing about it

Calgary

April 30, 2008 1:18 AM  

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