Many male birds have elaborate ways to attract mates. Blue-footed boobies show off their fabulous feet with a dance; bowerbirds decorate their nests with brightly colored sticks and flowers.
Brazil's white bellbird has its own special trick: When it gets close to an interested female, it takes a deep breath, pivots toward her, then screams in her face.
Or tries to, anyway — often the female sees it coming and hops away before the full blast hits.
Regardless, the scream is really loud. In fact, researchers from the University of Massachusetts Amherst and the Instituto Nacional de Pesquisas da Amazônia report that the mating cry of the bellbird is the loudest bird call ever measured, topping out at around 125 decibels. That's louder than a jackhammer, a pile driver or the bellbird's relative, the screaming piha. The observation was reported Monday in the journal Current Biology.
While there are anecdotal reports of louder birds, Russ Charif, senior bioacoustician at the Cornell Lab of Ornithology, said via email that he's "not aware of any peer-reviewed scientific papers documenting a louder bird sound."
The sound resembles an industrial fire alarm, the type usually accompanied by a flashing red light and an urge to flee. But UMass biologist Jeff Podos, co-author of the new paper, calls the cry “beautiful.”
"For me, it defines the forest where we work. I find it quite musical."UMass biologist Jeff Podos
"For me, it defines the forest where we work," he says. "I find it quite musical."
Still, Podos admits it would be hard to bear the noise up close, which is how the male bellbird prefers to deliver his gift to the female.
"The presumption is that for some reason, being able to sing these loud songs helps males in their attempts to court females," says Podos. "And the females — they must somehow be be attracted to this, or favor males who sing like that."
There is "strong evidence" the birds are singing as loudly as they can, he adds, since the loudest calls also tend to be the shortest. The males "are just giving it their all," he says. "They're devoted to their craft."
Bellbirds are small, about the size of a dove, and Podos says this makes their song all the more impressive. He guesses that their extraordinarily wide mouth — which they evolved to eat fruit — acts like the flared end of a trumpet and amplifies their calls.
But Podos says more research is needed to find out exactly how the small birds make these huge sounds, and whether their sexual gambit actually pays off.