Louder than Elephants and Saws.. Two Birds Confound Scientists

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In the depths of the "Sierra do Mar" mountains in Brazil, a sharp metallic ringing penetrates the density of the forest, originating from a bird no larger than a pigeon.. It is the "bare-throated bellbird," which emits calls to attract females with a sound intensity that may exceed that of elephants, pneumatic hammers, and power saws, according to a new study that revealed some of the secrets of bird noise.

The study, published in the journal "Evolution," showed that the bellbird and the "red-legged seriema" are among the loudest birds known to science, joining another type of bellbird that has previously documented its extraordinary capabilities.

The two birds recorded sound levels ranging between 121 and 122 decibels, compared to about 50 decibels for some hummingbirds, which is similar to the sound of moderate rainfall.

The bellbird lives in the Atlantic forests and is characterized by a clear metallic call, while the seriema inhabits savanna areas, is similar in length to a crane, and produces complex and melodious calls.

The lead author of the study, João Menezes, explained that these sounds can surpass the calls of much larger animals, including lions, wolves, and bison. Meanwhile, co-researcher Jeff Buddle noted that the uniqueness of bellbirds lies in their ability to produce this racket despite their small bodies.

Sound production in birds is linked to an organ known as the 'syrinx,' where tissues vibrate as air from the lungs passes through, while the trachea helps shape the sound and enhance certain frequencies, similar to the tubes of brass musical instruments.

Comparisons also revealed the role of bill shape and body size; broad bills help radiate sound in a manner akin to the flared end of a trumpet, while larger muscles allow for higher air pressure that supports powerful calls.

But away from the racket, the Australian superb lyrebird presents a different display, based on accurately mimicking sounds. According to the Australian Museum, mimicry makes up about 80 percent of its song, which may include calls of birds, barking dogs, and the sounds of engines and saws it hears in its surroundings.

The National Film and Sound Archive of Australia holds a recording of a bird called 'Chook,' in which it seems to mimic an electronic game. However, the archive clarifies that mimicking human and mechanical sounds remains rare compared to the mimicry of other birds in nature; the prevalence of these clips does not mean that all lyrebirds produce the same sounds.

In Ecuador and Colombia, the mention of the "winged manakin" does not only involve the usual singing to attract females; it also produces a tone with its wings that resembles the sound of a small violin. The Cornell Lab of Ornithology describes this display as a resonant sound accompanying the movement of the wings behind the back, in a scene that combines dance with music. Its peculiarity lies in the fact that the tone comes from the wings.

As for the African "fork-tailed drongo," it sometimes uses sound for deception. A study documented its release of false alarm calls, including mimicking the alarms of other species, when it sees animals holding food.

Once the animals flee to safety and leave their meal behind, the drongo swoops in to seize it. Thus, the call that is supposed to warn of danger becomes a means of obtaining food, in one of the strangest documented uses of sound among birds.