Within the family, the Screaming Piha has also evolved a loud call. Intense female selection is a theme among most birds of the cotinga family, leading to bizarre attributes like extravagant courting behaviors and superbly bright plumage. There are lots of arts, whether it’s symphony or rock and roll, where volume is impressive-it’s just another brilliant color.” “Extreme volume can become aesthetically elaborate. “All the different species have gone into different aesthetic directions, just like genres of art,” says Prum, a cotinga expert. In other words, females actually prefer and encourage louder males. Loudness is definitely not a survival tactic-it increases the male’s risk of being detected by predators-so the researchers came to the conclusion that it must be a product of female choice. The female would always retreat as or just before the song began, but would remain in close range. In these interactions, the suitor would turn his back to the female, then dramatically swivel around to face her as he bellowed the song’s second note. On several occasions, the researchers observed females joining the males on their display perches. “She is effectively sticking her head in a speaker at a rock concert,” Cohn-Haft says. They were also fascinated by how females, and the vocalist himself, can endure the calls without hearing damage. Since loud sounds are usually associated with long-distance communication, the researchers were surprised to observe that the males save their loudest calls for when a female is close by. Females, on the other hand, have green plumage accented with streaks of brown. The males are bright white with a striking black bill that has a wattle dangling from its top. Part of the cotinga family, which includes umbrellabirds, pihas, and cocks-of-the-rock, White Bellbirds typically live in the high mountains of northern Brazil and southern Venezuela. “They did an extremely good job of controlling for those elements.” “Volume is one of the hardest things to actually measure empirically in the wild because there are so many other elements that can interfere with accurate measurements,” Prum says. Richard Prum, an ornithologist at Yale University who was not involved in the study, says it’s impressive that the researchers were actually able to measure the bellbird's decibel level. The two trekked into the mountains last December and again this February with calibrated sound level meters to record the amplitude of White Bellbird and Screaming Piha calls, which they adjusted for noise and distance to allow for comparison. Curious to find out how loud the bird actually is, he contacted Jeff Podos, a bioacoustician at University of Massachusetts Amherst.
“They give out these loud ringing sounds that sound like someone banging on metal, like a blacksmith.”Ĭohn-Haft became familiar with the sound through his expeditions in the mountains of the Brazilian Amazon. “We could hear them all over the place, they’re kind of the soundtrack of these forests,” says Mario Cohn-Haft, one of the study’s authors and an ornithologist at Brazil’s Instituto Nacional de Pesquisas da Amazônia. Its short, booming, two-part call is three times the sound pressure level-a measure of sound intensity-of the Screaming Piha’s call, the previous record-holder. In fact, the White Bellbird has the loudest bird call ever documented, according to a paper published today in the journal Current Biology. Although it’s only about the size of a pigeon, this South American bird has a call louder than the howl of a howler monkey, and comparable to the hammering of a pile driver. But if your alarm clock was the male White Bellbird’s mating call, it would be more like waking up to the blaring of a fire alarm. Birdsong can be the perfect wake-up call for mellow mornings, with soft chirps and gentle warbles that ease you out of a deep slumber.
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