Media release

From: The Royal Society

Noise constrains heterospecific eavesdropping more than conspecific reception of alarm calls

Biology Letters

Animals are often warned of danger by their social companions, but also eavesdrop on the alarm calls of neighbouring species. But the increasing noise of our modern world may make such eavesdropping difficult. We tested whether noise makes it especially difficult for wild birds to eavesdrop on other species, compared to hearing calls from their own species. We found that fairy-wrens and scrubwrens understood each other during quiet times, but struggled when it was noisy. So our noisy world may jeopardise animal safety by smothering neighbourhood warnings of danger.

• Wrendered inaudible – In a noisy world, animals struggle to hear the warning calls of other species. In the Australian National Botanic Gardens, superb fairy-wren and white-browed scrubwren alarm calls were played to each species, eavesdropping birds understood the calls when it was quiet, but were less likely to flee when warning calls played amid background noise. Increasing noise pollution could compromise species’ survival if danger signals become harder to hear. Biology Letters