Noise pollution threatens songbirds in towns and cities

Many of our feathered friends communicate with “birdsong,” which is tuneful messaging that they employ to find mates and signal ownership of a territory.

So far so good. The trouble is that in urban areas birds tend to find it harder to communicate with their songs because of noise pollution from us. A team of researchers from Queen’s University Belfast ascertained this by studying European robins (Erithacus rubecula).

The scientists focused on the birds’ song complexity, sender aggression and affected receiver response, which is to say they studied how aggressively these birds communicated and how well they received messages from other birds. They found that sonic interference from humans limited the songbirds’ ability both to send signals and to receive them accurately.

“We found that bird song structure can communicate aggressive intent, enabling birds to assess their opponent,” said Gareth Arnott, a researcher at the Institute for Global Food Security at Queen’s University Belfast. “But human-made noise can disrupt this crucial information passed between them, by masking the complexity of their songs used for acquiring resources, such as territory and space for nesting.”

The result is that the birds may end up receiving “incomplete information on their opponent’s intent and do not appropriately adjust their response,” the scientist noted. “Where song is disguised by background noise, in some cases the male ends up fighting more vigorously than he should, but at other times gives in too easily.”

Perhaps the results of this new study should come as no surprise. We’ve long known that urban environments interfere with birds. Light pollution can cause migrating birds to perish because the birds often mistake such lights for stars at night and thus lose their way and fly into buildings. Even common sparrows are having it hard in cities across much of the world.

Songbird is crucial to the survival of species like European robins and the findings of the latest study raises concerns about the birds’ ability to cope with noise pollution from humans. “[H]uman-made noise pollution impacts animal habitats and directly influences their ability to communicate properly, which may have implications for survival and population numbers for birds,” Arnott said.