Male bats do sing to woo potential mates, but unlike most birds they can also use sound to navigate and hunt food. In fact, bats use noise for many types of communication – for example, distress calls, chittering within a roost, and pups calling for their mothers. Social calls tend to be much lower in frequency than the ultrasonic ‘tweets’ of echolocation calls. In some species calls are even low enough for humans to hear.
Social calls also tend to be more complicated, sounding like a series of undulating trills that are quite beautiful to hear. In the UK the most common time to hear bat social calls is in early autumn when bats start mating and preparing for winter. One West African species, the hammer-headed fruit bat (Hypsignathus monstrosus), has some of the loudest bat courtship calls, where males gather in groups or ‘leks’ and use their huge noses and voice boxes to produce deafening honking sounds to attract the ladies.