The birds of the Galapagos Islands gave Darwin some of his best evidence for evolution. Now some of those birds have evolved an extreme dislike of all the noise of this increasingly busy tourist destination.
A new study suggests that traffic noise affects the behavior of the Galapagos yellow warbler. The little yellow birds are altering their songs, and the males have become more aggressive. Think of it as the avian version of road rage.
Birdsong is a crucial tool for male warblers to defend territories from rivals. External noises, such as traffic, hamper the effect of their songs. Rather than fend off competitors with their vocal stylings, the little birds resort to physical aggression instead.
Researchers from Anglia Ruskin University and the Konrad Lorenz Research Center carried out experiments at 38 sites across the islands of Floreana and Santa Cruz. Researchers played recorded bird songs in all those locations, mimicking an intruder. Some songs had accompanying traffic noise, and others did not. The responses varied significantly based on how close the birds lived to the road noise.
Photo: Shutterstock
Change of tune
Warblers near roads were aggressive when the combined sounds of rival bird songs and traffic played. They approached the source of the sound, increased their physical displays, and prepared to fight. By comparison, birds in quieter, more remote areas showed far less aggression. Researchers believe this is due to their unfamiliarity with traffic noise.
The warblers also changed their singing because the traffic noise masked their normal birdsong. To counteract this, the clever birds adjusted the frequency of their singing so that their calls were still audible over ambient traffic.
“We have to think about noise pollution even in places like the Galapagos,” co-author Çaglar Akçay told The Guardian. “The results of the study are clear: Human-induced noise pollution is affecting wildlife behavior, even in remote and protected regions like the Galapagos.”
The Galapagos warbler prefers the slow, quiet life to a hectic, noisy one. Photo: Jerry Kobalenko
