People love robins. They are cute little birds with very nice voices. In Britain they are associated with Christmas and there are plenty of fairy tales and songs mentioning these birds. They are quite aggressive when it comes to defending the territory though – they lower their voices to sound bigger and meaner to the intruder. Now scientists say that wind turbines alter robins‘ behaviour and they have to rely on other weapons.
Scientists from the Newcastle University say that without any background noise robins simply sing on lower pitch when there are intruders. It could be an attempt to sound bigger and more dangerous for an uninvited guest – sort of like waving your arms around in front of a bear. However, wind turbines are rather loud and robins have to adapt. In these areas where wind turbines are present, robins drop their lower pitch and go for the trademark puffed up red chest instead. Little birds cannot compete against the low hum of the wind turbine blades.
This lower pitched singing is rather an effective weapon. It allows robins scaring off the intruder without actually getting into a fight. Avoiding fighting helps robins to preserve energy and avoid getting injured. Puffing up a red chest works in a similar way – it makes the tiny bird appear bigger and stronger, but it is not as effective, because it only works when the intruder can already see the robin. Scientists wanted to see what is the impact of human activity on the behaviour of robin’s songs. At first they researched the influence of urban noise pollution – traffic and other human activity. But wind farms are not even close to cities – they are situated in more rural areas, where their noise pollution levels are even more damaging.
Scientists wanted to see how wind turbine hum affects robin’s songs. So they went to the outskirts of Newcastle upon Tyne and studied bird calls between 06:00hrs-11:00hrs during April. This time of year is a busy breeding season, when establishing and defending territory is very important. Scientists managed to record 911 songs from 24 robins and found 25 % decrease in the use of low-frequency song elements with wind turbine noise in the background. Mark Whittingham, one of the authors of the study, said that there are two possible explanations for this: “One is that, unable to compete against the noise, they switch to alternative defence behaviours such as visual cues and puffing out their red breast. The second is that they may be simply trying to find a way to be heard over the noise”.
Human activity is constantly messing up with natural ways of nature. However, it is interesting to see that robins are trying to adapt. Maybe in a few years we will see a completely new way they use to defend their territory in a presence of wind turbines.
Source: Newcastle University