Traffic Noise is a Danger to Wild Birds
There is no doubt that traffic noise impacts human quality of life. From ruining otherwise peaceful days in the garden to keeping us awake at night, traffic noise is a major irritation. But what about birds? Are wild birds troubled by the incessant roar of vehicles thundering past? If so, how does it affect their daily lives?
Two researchers in New York decided to investigate the issue and discovered that excess background noise can threaten birds’ survival. Wild birds rely on their hearing for their safety and so the noise from our busy roads represents a serious problem.
Megan Gall, Assistant Professor of Biology at Vassar College, teamed with Jacob Damsky, a recent graduate and biology major. They wanted to learn more about how traffic affects birds and set up an experiment involving black-capped chickadees and tufted titmice. In order to compare the bird’s behaviour with and without the influence of traffic noise, the experiment was conducted in a quiet area using recorded noises which could be turned on and off.
Interrupting Alarm Calls
Speakers were used to play the birds’ alarm calls, traffic noise and a mixture of both and bird seed was provided to attract the birds to a defined area. Gall and Damsky discovered that the traffic noise did not deter the birds from feeding but that five times as many birds approached the speakers emitting alarm calls when there was no traffic noise. In other words, the sound of vehicles was masking the alarm calls and so was leaving the birds vulnerable to predation.
The study, "Anthropogenic noise reduces approach of Black-capped Chickadee (Poecile atricapillus) and Tufted Titmouse (Baeolophus bicolor) to Tufted Titmouse mobbing calls," was published in the journal The Condor: Ornithological Applications.
Human Activity and Wild Birds
Human activity is interfering with the transmission of information between birds. Extraneous noise is leaving birds vulnerable to predation because they cannot hear other members of their social groups issuing alarm calls.
For wild birds, the noise from busy roads isn’t just an irritation. Traffic drowns out bird song and so prevents vital communications from getting through. The ground breaking study of black-capped chickadees and tufted titmice may be followed up by further research as our understanding of avian communication is still limited. It is likely that human activity affects birds in more ways than previously thought.