Data from: Non-breeding European robins adjust their songs in noisy environments

Noise pollution is a global threat to biodiversity, significantly
affecting acoustic communication in birds and other taxa. While European
robins (Erithacus rubecula) adjust their songs in response to urban noise
during the breeding season, little is known about song adjustments during
the non-breeding season, when song plays a crucial role in survival by
helping secure winter territories with adequate resources and shelter. To
better understand the effect of noise on avian communication, we
investigate whether robins modify their non-breeding song in noisy
environments. We analysed the autumn songs of 25 robins exposed to varying
background noise levels and found that robins increase the minimum
frequency of their songs and extend phrase duration by singing fewer but
longer syllables per phrase in noisy environments—adjustments that may
mitigate acoustic masking. Our results provide valuable insights into the
broader impact of urbanisation on bird communication and highlight the
need to consider non-breeding vocal behaviour in conservation efforts.
These findings underscore the year-round impact of noise pollution on
birdsong, suggesting it affects various aspects of avian life history.
However, it remains unclear whether these adjustments have evolutionary
consequences for survival, as changes in key song parameters may affect
how rivals interpret signals. Therefore, future studies should explore how
vocal plasticity influences winter territory quality, predation rates, and
individual survival.