Researchers reporting in the journal Current Biology, on October 21, 2019, have captured the loudest bird calls yet documented. The calls are the mating songs of male white bellbirds, which live atop mountains in the Amazon region of northern Brazil. The open-access Current Biology article is titled “"Extremely Loud Mating Songs At Close Range In White Bellbirds.” The calls have a sound pressure about three times that of screaming pihas, now the second loudest bird singer that's been documented. In fact, the calls are so loud that the researchers are left to wonder how white bellbird females listen to them at close range without doing permanent damage to their hearing. "While watching white bellbirds, we were lucky enough to see females join males on their display perches," said Jeff Podos, PhD, of the University of Massachusetts, Amherst. "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." "We would love to know why females willingly stay so close to males as they sing so loudly," he says. "Maybe they are trying to assess males up close, though at the risk of some damage to their hearing systems." The researchers say it's hard to describe just how loud the call really is because it's tough to make comparisons between sounds heard at different distances. Dr. Podos says that the howls of howler monkeys and bellows of bison are well studied and are both pretty loud. But they are not nearly as loud as the songs of bellbirds. That's especially impressive because of the bellbird's tiny size in comparison to those mammals. Bellbirds weigh only about a quarter of a kilogram.
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