The male white bellbird, a 250-gram-heavy bird native to South
America, produces the world’s loudest bird sound, according to a new
scientific study.
Biologist Jeff Podos at the University of Massachusetts Amherst and
Mario Cohn-Haft of Brazil’s Instituto Nacional de Pesquisas da Amazonia
recorded the mating call of the male white bellbird, aka Procnias albus, and
concluded that it was a good nine decibels louder than the sound of the
previous holder of the title “world’s loudest bird”, the screaming
piha, also a species native to the Amazon rain forest. Peak sound levels
recorded during the bird’s mating call reached a whopping 125.4
decibels, way above the human pain threshold and equivalent to the sound
made by a pile driver.
In their study, published in the journal Current Biology,
the two researchers wrote that the sound of the male white bellbird was
so loud that it left them wondering how females can listen to it and
not have their hearing seriously damaged. They did mention that even
though the female white bellbirds sometimes join the males as they sing,
they make sure to get out of the way for the highest notes.
“He sings the first note facing away, and then he does this dramatic,
almost theatrical swivel, where he swings around with his feet wide
open and his wattle is kind of flailing around,” Professor Podos said.
“And he blasts that second note right where the female would have been,
except the female knows what’s coming and she’s not going to sit there
and accept that so she flies backwards.”
It’s not clear why females expose themselves to sounds as loud as 113
decibels at the risk of having their hearing apparatus damaged, but
researchers suspect that they are trying to asses the males from
up-close.
Researchers used high fidelity sound recorders and high definition
video to record the white bellbirds’ mating calls and slow down the
action to understand how such a small creature – about the size of a
pigeon and weighing 250 grams – is capable of producing such loud
sounds.
“We don’t know how small animals manage to get so loud. We are truly
at the early stages of understanding this biodiversity,” Jeff Podos
said, adding that the sound is much louder than those produced by much
larger creatures, such as howler monkeys or bison, but not quite as loud
as the sounds made by lions or elephants.
One thing the researchers were able to identify was that the louder
the white bellbirds’ mating calls got, the shorter they became, which
hints at a trade-of, as the bird’s small respiratory systems only have a
bit of airflow to generate sounds.
