The Evolution of a City Birds Song

Communication is an important part of any animal’s life and a study has shown that birds which now live in suburban areas are starting to change their tune (Brumm, 2006). Many people today complain about the increase in the surrounding noise, but what people do not realise is that the noise is of just an annoyance to them but it also affects the animals as well (Brumm, 2006). This increasing urbanised area and the noise associated with it is becoming problematic for the wildlife around (Brumm, 2006).

The noise of an urbanised area is a problem for bird communication as their signals are being asked by this noise and thus prohibiting the exchange of important information (Brumm, 2006). The major problem for birds is that in cases such as mateship where the male uses their song to attract females and defend their territory is becoming harder with the addition of this noise (Brumm, 2006). There was a study on the urban nightingales which found that the males adjusted their sound level depending on the sound level of the traffic around them (Brumm, 2006). Birds do have one advantage.

The traffic of the urbanised area is generally from automotive vehicles which although they are all different they have one thing in common, they are all low frequency noises (Brumm, 2006). Birds have a high-pitched song which comes at the bird’s advantage in this area as their songs become less masked by the surrounding noises of the area (Brumm, 2006). As a result, city birds have a higher minimum frequency than forest birds (Brumm, 2006).

Even though it looks like this change only occurs in urbanized areas, this characteristic change has also occurred in bird species which live in woodlands close to natural noise sources such as waterfalls and rapids (Brumm, 2006). No matter whether the noise comes from a natural or man-made sound, the birds in the surrounding area have evolved to survive in that particular area. 

For another example of this amazing evolution in the birds song, take a look at this David attenborough video of the lyrebird. 

 https://www.youtube.com/watch?v=mSB71jNq-yQ

Works Cited

Brumm, H., 2006. Animal Communication: City birds have changed their tune. Current Biology , 16(23).