Male bell ringers take care of females, striking them with the loudness of their song, and are able to “shout out” even an airplane.
In the mountainous and wooded area in the north of the Amazon, medium-sized relatives of sparrows are widespread - the single-horned bell-ringers Procnias albus, the loudest birds in the world. In addition to the striking white coloration and the unusual "mustache" above the beak, male bell ringers attract females with a song, the volume of which is at least nine decibels higher than the previous record set by their neighbors in the Amazonian jungle, the loud spikes Lipaugus vociferans.
The loudness of the song, which males of P. albus captivate their females, can reach a level of 125 decibels, which is dangerous for our hearing and health. For comparison, the volume of a fire siren reaches 100 decibels, and the sound rises to 120 decibels near the operating aircraft engines. It is worth recalling that bel is a logarithmic unit, and the difference between the loudness of the pikhi and the bell ringer "only" in nine decibels corresponds to a threefold difference in sound pressure. American ornithologist Mario Cohn-Haft and his Brazilian colleague Jeffrey Podos write about this in an article published in the journal Current Biology.
In the course of field observations, scientists measured the loudness of the singing of three pikh and eight bell ringers in natural conditions and from different distances, accurately recording the distance to the bird. This made it possible to easily calculate the loudness that 250-gram single-whiskered bell ringers are capable of and set a new record. The authors note that small birds are perfectly adapted for loud songs, are distinguished by thick muscles of the "press" and the ability to open their beak especially wide.
Of course, issuing such loud cries, even the fittest bird quickly depletes its air reserves. Therefore, the songs of one-whiskers bell ringers do not differ in length and melody. The loudest of these are a series of short shouts. But the most curious thing is that, unlike most other animals that can make very loud sounds, for example, whales, bell ringers do not use them for communication over long distances.
Their loud song is the same element of the mating ritual, the result of sexual selection, like the horns of elk or the tail of peacocks. The male performs it not at all from afar, but "shouting" almost directly into the ear of his chosen one. Perhaps scientists should now figure out how female bell ringers can tolerate such courtship without damage to their hearing or injury.