Loud, loud birds

404 Media reports on two new contenders for the world’s loudest bird — the bare-throated bellbird and the red-legged seriema — both of whom can make noises in their Amazon rainforest home that are louder than an industrial jackhammer:

These two bird species are now in the same league as the white bellbird, which shattered the record for loudest bird in 2019 after its bizarre call was first measured and reported by Jeff Podos, a professor in the department of biology at the University of Massachusetts Amherst.

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In the new study, Podos and former UMass Amherst graduate student João C.T. Menezes report that the bare-throated bellbird and the red-legged seriema occupy the same decibel range as the white bellbird. It’s tough to declare a clear winner among the three birds due to differences in measurement techniques and individual variations within each species.

Regardless, this trio is a special class that is much louder than the fourth runner-up, the screaming piha, which tops out around 116 decibels. In addition to identifying the ear-splitting avians, the team captured unprecedented measurements of vocal amplitude in 123 bird species, an effort that represents “a step forward in uncovering what enables birds to produce the loudest acoustic signals of all terrestrial fauna,” according to the study.

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But unlike call features like tempo or frequency, vocal amplitude has been notoriously difficult to measure in the wild because it is dependent on distance to the animal, which can be tough to figure out in remote field environments, such as the Amazon rainforest.

Menezes and Podos were able to overcome this longstanding hurdle with the same laser rangefinders used by golfers to gauge the distance to holes.

“The laser rangefinders help us determine the distance between the recorder and the bird, which is important in our report as it allows us to correct our recordings of amplitude for distance,” Podos told 404 Media in an email. “But the actual recordings and thus readings of amplitude are made with another kind of device, a Sound Level Meter (normally used in industrial acoustics, but that can also serve in working with animals!).”

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There’s video at the link. You can read more about the awesomely earsplitting avians here, in Evolution.