As the human population increases in size, urbanisation naturally increases alongside it. This is often a positive thing for us humans – more industry, more infrastructure, more opportunities, more… noise, more of pretty much everything!! Except nature, that is.
Changes in the distribution of our own species has increasingly altered the abundance and distribution of others, but whilst many species have been driven out of their natural habitats, some have decided to adapt to city living. That doesn’t mean that they’ve managed to land themselves a job at an advertising firm or that they’ve figured out how to operate the tube (although their guess is probably as good as mine) but rather, they have changed something about themselves in order to find their place in the busy city. We can all relate.
In fact, a number of studies have found that many bird species are capable of changing their vocalisations to compensate for all of the hustle and bustle. Chaffinches, house finches and mountain chickadees, to name a few, have been found to sing notes in a higher pitch than usual to ensure that they’re not being masked by the low-frequency noise of traffic pollution. Other birds have different ways of getting their voices heard, for instance, the great tit might not alter the frequency of the notes used in any particular song, but they will choose to sing songs from their repertoire that contain less notes that are likely to be masked by anthropogenic noise. Depending on the species, song changes might occur over an evolutionary timeframe, or they can occur relatively quickly if a bird has the advantage of being plastic in their singing behaviours. In an ever changing world, it’s likely that the birds that can change their tune quickly will be the ones that survive and thrive in the city. I’m just hoping that we don’t lose some of these beautiful sounds to all the commotion.
LaZerte, S., Otter, K. and Slabbekoorn, H. (2017). Mountain chickadees adjust songs, calls and chorus composition with increasing ambient and experimental anthropogenic noise. Urban Ecosystems.