According to one study, robins in rural areas become more physically aggressive when exposed to traffic noise.
Red-breasted birds are fiercely territorial and rely on both visual and acoustic signals to mark their territory and keep other individuals away.
They change their behavior when threatened.
The researchers believe that while urban robins are used to temporary increases in noise levels and learn to keep them out, rural robins are instead compensating for increased physical aggression.
In a study, scientists from Anglia Ruskin University and Koç University in Turkey examined the behavior of male robins (Erithacus rubecula) living in urban and rural areas.
They measured aggression towards intruders using a 3D model of a thrush.
The model bird was accompanied by recordings of robin songs, while additional traffic noise was added via a separate speaker nearby.
By recording the birds’ behavior during their interaction with the simulated intruder, the researchers noticed that urban thrushes typically display more physical aggression than those in rural areas.
However, with the addition of traffic noise, rural robins have become more aggressive.
Scientists believe that physical displays of territoriality are increased because traffic noise interferes with thrushes’ signaling behavior using song.
In addition to adapting their songs to fend off intruders, robins adopt certain visual displays during territorial interactions.
These include waving and displaying the red feathers on their necks, approaching and chasing an opponent.
D., senior lecturer in behavioral ecology at Anglia Ruskin University and senior author of the study. The noise produced can have a variety of effects on thrushes depending on the habitat they live in.
“We found that in a normally quiet environment, additional traffic noise, such as getting closer to the model bird, causes rural robins to become more physically aggressive, and we believe this is because the noise interferes with their communication.
“Chronic high noise levels that exist day and night in urban habitats such as traffic or construction equipment can permanently impede the efficient transmission of acoustic signals, and this may be the main reason why urban thrushes are typically more aggressive than rural birds.
“It should be emphasized that physical aggression is a risky behavior for small birds such as robins and is likely to have health consequences.”
During tests on urban robins that already live in noisier habitats, simulated traffic noise did not affect physical aggression levels.
But the birds adapted to the additional noise by reducing their call rate.
Lead author Çağla Onsal, who conducted the research while studying at Koç University, said, “Signals are extremely useful because they can deter intruders without a fight that can cost both the territory owner and the intruder. cannot be heard by the intruder, thrushes may have to resort to physical aggression.
“However, this not only increases the risk of injury, but also displays of aggression can draw attention to predators such as hawks.”
The study was published in the journal Behavioral Ecology And Sociobiology.