'Loud as a jackhammer': Scientists identify world's loudest birds

Scientists have confirmed two new contenders for the title of the world's loudest bird, with calls loud enough to rival the noise of a construction drill.

According to CNN on Monday (local time), researchers at the University of Massachusetts Amherst recently published a study finding that both the bare-throated bellbird and the red-legged seriema produce calls exceeding 120 decibels. The research was published in the journal Evolution.

João Menezes, an evolutionary biologist and co-author of the study, told CNN that the calls of both birds most closely resemble "a jackhammer — a tool used to drill through rock."

The two species were found to produce sounds comparable to those of the white bellbird, previously considered the loudest bird in the world.

The bare-throated bellbird's call measured an average of 122.4 decibels at a distance of one meter, with individual peak readings approaching approximately 131 decibels.

Which bird holds the title of "world's loudest" depends on how loudness is measured.

When averaged over 20-millisecond intervals, the red-legged seriema came out on top at around 121 decibels. When peak readings across multiple individuals were averaged, however, the white bellbird led at approximately 127 decibels.

Experts said this makes it difficult to crown a single bird as the loudest.

Larger birds capable of opening their beaks wider tended to produce louder calls. Researchers believe bigger birds have larger, stronger vocalization muscles that generate greater pressure, while a wider beak opening allows more sound energy to project outward.

However, some birds were found to be louder than animals far larger than themselves — such as elephants, lions and bison — suggesting other biological mechanisms have yet to be identified.

"Only a tiny fraction of all bird species have had their calls measured so far, so there is a real possibility that even louder species remain to be discovered," the researchers said.