These South American Birds Can Match a Jackhammer's Ear-Splitting Volume, Making Them Some of the World's Loudest Known Avians

From soft peeps to piercing calls, birds produce a wide range of sounds. But scientists recently discovered that two South American species take their calls to ear-splitting extremes, making deafening vocalizations on par with a jackhammer. The bare-throated bellbird and the red-legged seriema can produce sounds at amplitudes that exceed 120 decibels, according to a study published September 29 in the journal Evolution.

They’re now among the ranks of the white bellbird, another South American species, for the loudest known birds on the planet. Researchers behind the new work didn’t specifically set out to find the world’s noisiest birds. Rather, they wanted to take advantage of recent technological advancements that have made it easier to measure vocal amplitude, the height of a sound wave and a key element of loudness.

They used a laser rangefinder to measure their distance from a specific bird, as well as a sound level meter, which allowed them to isolate that bird’s call from other noises. The scientists ultimately collected amplitude data on 123 bird species between December 2018 and January 2025, filling a major gap in scientists’ understanding of how loud birds can sing. Previously, scientists only had amplitude data for ten of those species—even the ubiquitous Canada goose had never been measured.

At the low end, they documented the dusky-throated hermit, a hummingbird that buzzes at a modest 64 decibels, about the same volume as a normal conversation. At the high end, the bare-throated bellbird and red-legged seriema are both about as loud as a trumpeting elephant or a chainsaw. Comparing the amplitude data with the birds’ anatomy revealed that species with bigger bodies and wider mouth openings also tended to be the loudest.

This is probably because “bigger birds have bulkier muscles, which are capable of creating greater internal pressures, which ultimately generate louder sounds, and then broader mouths allow more energy to radiate into the environment,” Menezes tells CNN’s Amarachi Orie. Still, the researchers have many unanswered questions. The big one: Why are some birds so much louder than others?

The researchers hypothesized that the loudest birds evolved their high-volume calls to attract numerous mates, or to communicate through dense vegetation. But those explanations don’t hold up for the red-legged seriema, so there must be some other factor driving the evolution of its loud vocalizations. So, it forms a pair for the breeding season, and that’s it.” There’s no single answer to the question of which species holds the title of “world’s loudest bird”—it depends on how researchers define loudness.