The researchers making field recordings of white bellbird also noted a runner-up: the screaming piha (Lipaugus vociferans) can woo females at a peak volume of around 116 db on average, and has been previously documented as the loudest passerine bird. Nice try fellas, but you're being out-screamed. (Thankfully, the video below is at a safe-for-human-ears volume.) "While watching white bellbirds, we were lucky enough to see females join males on their display perches," says biologist Jeff Podos, from 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. Maybe they are trying to assess males up close, though at the risk of some damage to their hearing systems." There is a trade-off though: as the calls of these birds get louder, they also get shorter. That's quite possibly to do with managing airflow. While white bellbirds only weigh around a quarter of a kilogram (just over half a pound) on average, they have unusually thick and well-developed abdominal muscles and ribs – most likely very important in producing mating calls of such volume. However, research into the bird and its singing habits is thin on the ground. For the purposes of comparison, a quiet office comes in at around 40 db, while your doorbell will typically ring at 80 db. The white bellbird beats out a symphony concert (110 db), a car horn (110 db), and a pneumatic drill (120 db). However, it's not quite up to the volume of an air raid siren (130 db), a jet engine taking off (150 db), or the pop of a balloon (157 db – over a very short duration). However, the white bellbird is unusual in how up close and personal it likes to get with its mate, and that's perhaps a subject for further research. "It is curious that one of the world's loudest birds sings only its highest amplitude song type in such close range communication," conclude the researchers in their published paper. "Animals normally reserve loud calls for communication over long distances, and some species are known to vocalise more softly when receivers are nearby." The research has been published in Current Biology.