A recent study found that birds that live closer to roads display more aggression than birds of the same species that live farther away from noisy vehicles, Mongabay’s Spoorthy Raman reported. Researchers looked at the behavioral differences of male Galápagos yellow warblers (Setophaga petechia aureola) on two islands of the Galápagos, an Ecuadorian archipelago in the Pacific Ocean known for its rich biodiversity. Within known territories of 38 male yellow warblers on the islands, the researchers played prerecorded songs of an intruding warbler on a speaker. To some recordings, they had added traffic noises, while the others only had warbler calls. Male yellow warblers tend to shoo away other males that wander into their territory with songs. On both islands, the researchers found the same pattern in response: Male birds that lived closer to the roads were more aggressive when the speaker played recordings of an intruding bird’s song with added traffic noise than those that lived far away from roads. The birds living closer to roads circled the speaker in closer proximity, rather than simply singing — behavior associated with aggression and higher risk of physical conflict. The birds also increased the lower-pitched noises in their song, presumably to be heard over the traffic noise, while those living far from the roads sang in higher pitches. “Many species may adjust their behaviors and be able to live near noise, but the most sensitive species are likely not able to change their behaviors or deal with the stress of daily…This article was originally published on Mongabay

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