There are two new contenders for the world’s loudest bird – and scientists are not being quiet about it. Researchers at the University of Massachusetts Amherst found that the bare-throated bellbird and the red-legged seriema both create songs at amplitudes above 120 decibels, according to a study published Tuesday in the journal Evolution. “The nearest comparison in everyday sounds would be a jackhammer,” study co-author and evolutionary biologist Joao C.T. Menezes told CNN. He conducted the research as part of his PhD, along with his former teacher, biology professor Jeff Podos. The egregious noise of the two birds competes with that of the white bellbird, which was found in 2019 to screech at volumes of up to 125 decibels and was crowned by Guinness World Records as having the loudest bird call. Since the bare-throated bellbird is a close relative of the white bellbird, the researchers “had a hunch” the species would be high in the ranking. Its shout was recorded at 122.4 decibels when measured from a standardized distance of 1 metre (3.3 feet), averaged over a 20 millisecond time block – a sound pressure that is 800 times that of the quietest species they recorded, the dusky-throated hermit, a species of hummingbird, which has a call of 64.1 decibels, according to the study. Which of the loudmouths actually takes the title of “world’s loudest bird?” It depends on the criteria you chose. For example, it was a bare-throated bellbird that achieved the loudest call out of all individual birds, with a call reaching a peak volume of almost 131 decibels across one metre. However, if you average the noisiest calls made by all the birds studied, over a 20 millisecond time block, then the red-legged seriema is the loudest at almost 121 decibels among two birds. But then, if you take the average of the peak volume that the calls of the birds reached at any given moment, the white bellbird comes out on top, measuring 127 decibels across six birds. The world’s loudest bird “depends on how one defines ‘loud,’ underscoring the difficulties in measuring loudness,” evolutionary biologist Catherine Sheard, an interdisciplinary fellow at the University of Aberdeen in Scotland who was not involved in the study, told CNN. Bigger birds blare better The loud calls were identified after researchers measured the vocalizations of 123 bird species in Massachusetts and Brazil between December 2018 and January 2025. The calls of 113 of those species had never been recorded before, according to a statement from the university. Recordings of the volume of birds’ calls has been limited due to operational challenges in the field. For example, researchers need to know how far away a bird is when making a call because distance affects how loud the call sounds. Yet, you might hear a bird but not see it, and then when you see it , the bird flies away or “stops singing altogether out of shyness,” Menezes said. However, the authors of this study were aided by using laser range finders, which are tools golfers use to find how far the hole is, Menezes added, enabling them to measure the volume of the birds’ songs and the distance at the same time. After correcting for background noise and distance, the researchers could compare the sound readings and compare them in relation to data on different birds’ body sizes and open beak widths. They found that larger species and species with broader mouth openings tended to sing louder. The researchers think this is because “bigger birds have bulkier muscles, which are capable of creating greater internal pressures, which ultimately generate louder sounds,” Menezes said, “and then broader mouths allow more energy to radiate into the environment.” Yet, some birds can sing louder than animals much bigger than them, such as elephants, lions or bison, which indicates another mechanism is at play that allows birds to be loud that is yet to be discovered, the researchers noted. They were also not able to conclusively say what environmental and evolutionary factors have led some birds to shout more loudly than others. For example, bellbirds live in forests and are polyamorous, so the researchers predicted they would make louder calls to communicate across dense woodland that obstructs their view and mate with as many birds as possible, Menezes said. However, loud red-legged seriemas are “strictly monogamous” and typically live in open habitats, so do not have the same reasons for being loud, Menezes added. Despite recording the amplitude of many birds’ calls, “it’s such a tiny fraction still,” Menezes said, adding that “there’s so much to answer yet.” “It doesn’t surprise me that even a relatively modest survey of volume has newly identified some very loud birds,” Sheard said. “As fieldworkers continue to collect more data on avian sound, I would predict that even more ‘loudest’ birds will be identified in the future.”
