Many people will show "road rage" in situations such as traffic jams. In a new study, researchers from Ruskin University in England and other institutions investigated the impact of vehicle noise pollution on Galapagos warblers and found that those Galapagos warblers exposed to vehicle noise also have a tendency to "road rage", that is, they show more aggressive behavior.
The Galapagos Islands belong to Ecuador and are about 1,000 kilometers away from the mainland of Ecuador. They are considered a natural biological laboratory because of their large number of unique species. Charles Darwin visited the Galapagos Islands during his round-the-world voyage and laid the foundation for the formation of his theory of evolution. However, in recent decades, with the rise of tourism, the local resident population has increased by more than 6% each year, resulting in an increase in the number of vehicles on the island.
The research team selected two islands in the Galapagos Islands for the experiment, involving a total of 38 locations where yellow warblers are more common. Among them, 20 locations are close to roads, and the other 18 locations are far from the road, more than 100 meters away. For the yellow warblers in the control group, the researchers only used loudspeakers to play bird calls to simulate intruders; while for the yellow warblers in the experimental group, in addition to playing the simulated intruder bird calls, they also played recorded traffic noise.
They then measured the warblers' calls, which are often used to repel intruders, as well as physical aggressive behaviors, such as approaching and repeatedly flying over speakers. The results showed that the experimental group of Galapagos warblers living near roads on both islands showed more aggression than the control group, while the experimental group of warblers living away from roads showed less aggression. In addition, regardless of whether their territory was close to the road, the experimental group of warblers increased the minimum frequency of their calls, which helped reduce the overlap of their calls with low-frequency traffic noise.
The relevant paper has been published in the international journal Animal Behavior. Corresponding author of the paper, Çalal Akçay, a senior lecturer in behavioral ecology at Ruskin University in England, explained that birds use chirping as attack signals in territorial defense, and if external noise such as traffic interferes with signal transmission, increasing physical aggression is an appropriate response. This research result highlights the impact of human activities on wildlife behavior. In animal protection work, it is necessary to consider the plasticity of wildlife behavior and develop strategies to reduce the impact of noise pollution on them.