Researchers measuring sound amplitudes in nature have identified the bare-throated bellbird and the red-legged seriema as two new avian contenders whose calls exceed 120 decibels, matching the volume of a jackhammer or chain saw and rivaling sounds produced by elephants and wolves in a study published in Evolution.
Measuring 123 Birdsong Amplitudes Across Brazil and Massachusetts
Scientists working in the wild documented 123 distinct birdsong amplitudes to build a comprehensive acoustic database. University of Massachusetts Amherst biologist Jeff Podos and former graduate student João C.T. Menezes conducted the research. The resulting database captures variability across species, ranging from hummingbirds whose tunes registered around 50 decibels—similar to the sound of moderate rainfall—to the deafening peaks reached by top-tier avians.
Measuring vocal amplitude in natural environments has historically presented a major obstacle because sound volume depends heavily on the distance between the recording device and the singing animal. For precise amplitude measurements, scientists must be capable of isolating a single bird from a group and determining its precise distance from the recording equipment. Using industrial sound level meters paired with careful fieldwork, the team was able to record the first clear amplitude measurements for dozens of species that had never been catalogued before.
“You have to get your boots on the ground,”
Jeff Podos, biologist
As Jeff Podos noted, getting out into the world and paying careful attention to sights and sounds takes researchers back to the roots of why they do science in the first place.
Bare-Throated Bellbirds and Red-Legged Seriemas Match White Bellbird Volume
The newly measured bare-throated bellbird and red-legged seriema join the Amazon’s white bellbird in an exclusive decibel tier. The bare-throated bellbird and red-legged seriema now rise above 120 decibels, placing them well ahead of the screaming piha, which tops out near 116 decibels.
“We were basically interested in finding out why some species sing louder than others. For that, the more diverse the sample, the better.”
João C.T. Menezes, evolutionary biologist and lead author
Lead author João Menezes, an evolutionary biologist, pointed out that these birds can even exceed elephants and lions and wolves and bison.
Anatomical Traits Driving Extreme Decibel Levels
By comparing anatomical features with acoustic readings, the research team identified physical traits that contribute to high volume. Broad beaks function similarly to the bells of brass instruments, enabling the birds to project sound more widely.
Birds also utilize specialized anatomical structures to help concentrate energy into a narrow range of frequencies, making it easier to hit louder peaks. According to Jeff Podos, this performs the same role as the tubing found in musical instruments such as a trumpet or a trombone.
The team had initially hypothesized that the loudest birds would share specific traits such as being weak flyers living in dense forests and practicing polygamy, but the top three birds served as perfect counterexamples. Because these divergent paths to extreme volume were unexpected, Menezes intends to further investigate the specific ecological drivers of high vocal amplitudes in his upcoming research.
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