Oct. 23 (UPI) -- Mating season in the mountains of northern Brazil can get pretty noisy, but no mating calls get louder than those produced by the white bellbirds.
Until recently, the screaming pihas, another South American songbird, held the record for loudest call. As scientists reported this week in the journal Current Biology, the pihas' record was shattered by the white bellbird.
During a recent expedition to the Amazonian forests of northern Brazil, researchers recorded mating calls produced by white bellbird. The calls produced a sound pressure about three times that of the screaming pihas.
"While watching white bellbirds, we were lucky enough to see females join males on their display perches," Jeff Podos, a biologist at the University of Massachusetts, Amherst, said in a news release. "In these cases, we saw that the males sing only their loudest songs. Not only that, they swivel dramatically during these songs, so as to blast the song's final note directly at the females."
Scientists aren't sure what purpose, if any, the record decibels serve in selecting a mate.
"We would love to know why females willingly stay so close to males as they sing so loudly," Podos said. "Maybe they are trying to assess males up close, though at the risk of some damage to their hearing systems."
Nature can be surprisingly noisy. The howls of howler monkeys are often cited as one of nature's more impressive sounds, with choruses carrying for miles across the jungle. Much depends on how close one is to the source, but authors of the latest study suggest the white bellbird's call is considerably louder than the howl of a howler monkey.
On previous field expeditions, scientists were struck by the thick, well-developed abdominal muscles and ribs of the white bellbird, but the scientific literature had little to say on this aspect of the bird's anatomy. The latest research suggest these muscles help the small bird, weighing just half a pound, produce its impressive call.
Recordings of the males' calls proved their pipes are not unlimited in their power. The loudest calls were also the shortest calls. In followup studies, scientists hope to more closely study the mechanics of the record-breaking calls.