Are urban birds becoming more aggressive because of noise?

Birds become more aggressive when they have to live in crowded and noise-polluted cities.

Yellow warblers become more aggressive when living in urban areas - Photo: MONGABAY

For many people, living in a crowded, dusty and noisy city can cause stress and discomfort. Not only that, many studies show that some bird species are also stressed and become more aggressive with urban life, according to Yahoo News on June 6.

An international research team has shown that Galápagos yellow warblers ( Setophaga petechia aureola ) living near busy roads in the Galápagos Islands of Ecuador react more aggressively to intruders than birds living further away from traffic routes.

Over the past several decades, the Galápagos Islands have seen a dramatic increase in human population, with permanent residents now increasing by 6% per year, bringing with them infrastructure and vehicles. This makes them an “ideal laboratory” to study how birds respond to new, crowded conditions.

The team selected 38 warbler colonies on the two Galápagos islands of Santa Cruz and Floreana. Both islands had a major road with heavy traffic, and the warblers lived close to the road and at least 300 feet away.

In each warbler territory, the team played traffic noise and the songs of other warblers to simulate an intrusion.

"We were interested in how yellow warblers responded to noise, which is often a stressor. Each bird was tested once with another warbler's song and once with warbler's song and traffic noise," said Caglad Akcay, of Anglia Ruskin University in the UK.

When exposed to songs mixed with traffic noise, warblers living near roads responded more aggressively to songs alone without traffic noise. They also reacted more violently to the noise than the “rural” birds, coming closer to the speakers and sometimes attacking them.

In general, animals that live in cities tend to be bolder and more aggressive – two traits that help them survive in such complex environments. They can be more aggressive when they have to fight a lot to maintain a territory large enough to get the resources they need.

In addition to yellow warblers, several studies have found that species such as great tit, European robin, sparrowhawk and black-eyed junco are more aggressive towards each other when living near urban areas.

Scientists are still trying to understand how much urban density different bird species can tolerate and which features of urban environments most influence their aggressiveness.

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ANH THU

Source: https://tuoitre.vn/chim-choc-o-thanh-thi-ngay-cang-hung-du-vi-tieng-on-20250606121456208.htm