LONDON, July 22 — Summer is traditionally the season of many music festivals, which is good news for music lovers, but not so good news for bats. These animals are highly sensitive to noise and can become disorientated by the noise generated by such events, according to a British study.

Researchers at the Universities of Bath and the West of England in the UK have been investigating the effects of noise pollution, particularly from music festivals, on these small mammals. To do this, they conducted an experiment at 10 sites in England and Wales, frequented by different bat species, over two nights. The first was a "control” night during which the scientists played no music, while they broadcast background noise (with an average sound volume of 42.82 dB) and 10-minute medleys (with an average sound volume of 98.74 dB). These medleys were composed of five tracks from different musical genres, to best recreate the diverse programming of most festivals.

The research team found a decline in nocturnal activity in all bat species studied when exposed to loud music. This was around 47 per cent for bats belonging to the Nyctalus/Eptesicus species, compared with 32 per cent for Pipistrellus pipistrellus. This makes them the bats most tolerant of the noise pollution caused by a music festival.

While some bat species are less affected by loud music than others, these mammals are not insensitive to noise. Nocturnal animals rely heavily on their hearing to glean the information they need to survive, whether it’s to orient themselves in space, find food, reproduce or avoid potential predators. Altering soundscapes can therefore hamper their ability to recognize and differentiate important acoustic cues, as the scientists explain in their study, recently published in the journal, British Ecological Society.

For Jack Hooker, lead author of the research, it is essential that music festival organizers gain awareness of this phenomenon in order to preserve the animals that live near the sites where they temporarily set up camp. "Given that music festivals have become ubiquitous in the UK and are increasingly being held in places that are important for local wildlife, it is imperative that guidance relating to their planning and implementation is evidence-based and fully protects local biodiversity from any potential negative impacts if we are to share these habitats with wildlife in a sustainable manner,” he said in a statement.

This study shows that bats are much more affected by ambient noise than has long been thought. But unlike us, they lose almost no hearing sensitivity when exposed to very high sound levels, according to a US study from 2016, even at levels of up to 140 dB, beyond the threshold of human hearing. — ETX Studio