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Traffic noise prevents birds from hearing danger alerts

A study published in The Condor: Ornithological Applications suggests that traffic noise makes birds less responsive to the alarm calls of other birds, which alert them to predator danger. Professors Megan Gall and Jacob Damsky of Vassar College co-authored the study, which gives new insight into the effect of human-caused noise on bird activity.

Gall expressed their curiosity for this issue, saying, “We were interested in how noise might affect responses to an anti-predator vocalization. These are evoked by presence of a predator and so are closely linked in time with a particular stimulus.”

To test how a busy roadway could affect how certain bird species react to alarm calls, the researchers studied birds’ responses to three different recordings – alarm calls alone, traffic noise alone, and a combination of the two. Feeding stations were set up with speakers for each recording, and the reactions of black-capped chickadees and tufted titmice were observed.

They found that traffic noise alone did not deter the birds from feeding, but five times as many birds approached the feeding station when the researchers played alarm calls on their own compared to when traffic noise was added over the calls.

It appears that the traffic noise may have masked the alarm calls, causing a completely different response than when the alarm calls were played alone. Gall says, “There has been lots of work on how anthropogenic noise affects vocal production, but much less response of animals to signals in the presence of noise.”

This may be an extremely important look into how human noise pollution can negatively affect the bird species that rely on these alarm calls to stay safe from predators.

Rindy Anderson, a bird communication expert at Florida Atlantic University, praised the study, saying “Gall and Damsky’s experiment helps us understand how human-caused noise can interfere with the transfer of information among animals in social groups.”

Given the significant findings of this research, more studies are sure to follow.

Credit: author Connor Ertz

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