Long preserved, this archipelago is home to unique species, including a bird called the Galápagos yellow warbler (Setophaga petechia aureola), a distant cousin of the American warbler.
But with the human population on the rise, automobile traffic is constantly increasing, and engine noise is disturbing the ecosystem and local wildlife.
Under the effect of the incessant din, the warblers’ melodious song changes. Less harmonious and more aggressive, it seems to reflect the chaotic soundscape of their surroundings.
To better understand this phenomenon, researchers from Anglia Ruskin University and the Konrad Lorenz Research Centre at the University of Vienna conducted an experiment on the islands of Floreana and Santa Cruz. They broadcast birdsong via a loudspeaker to simulate the intrusion of a fellow bird, adding traffic noise.
The results are revealing. The closer the warblers live to roads, the more testy they become.
Faced with intrusive sounds, they swoop down on the source of the noise, twirling relentlessly and adopting more belligerent behaviour than those living in the wilder environments.
Even on the island of Floreana, where there are only a handful of vehicles, this phenomenon is apparent.
Their song is also changing. On the more urbanised island of Santa Cruz, the warblers lengthen their vocalisations and raise their pitch to overcome the ambient noise.
By raising the frequency of their song, they manage to make themselves heard over the roar of engines.
Clearly, engine noise doesn’t just affect the patience of humans on the road, it also shapes the behaviour of wildlife, even in the most remote havens.
In the Galápagos, yellow warblers, exposed to this incessant din, are reinventing their language and toughening up their temperament.
“Birds use song during territorial defence as an aggressive signal. However, if external noise such as traffic interferes with the signalling, effectively blocking this communication channel, increasing physical aggression would be an appropriate response,” explained study co-author, Dr Caglar Akcay, senior lecturer in behavioural ecology at Anglia Ruskin University, quoted in a news release.
The findings serve as a reminder of the extent to which our noise footprint extends beyond urban boundaries. Invisible yet omnipresent, engine noise shapes the behavior of wildlife, even in some of the planet’s most unspoilt areas.