Toth and Parsons recorded and analyzed the vocalization of 16 lekking male lesser short-tailed bats. In the process, they identified four distinct notes used by male bats as part of their efforts to attract a female - upsweeps, downsweeps, trills and tones. These sounds were either uttered as single notes or combined into one of 51 different distinct syllables. On average, each male produced 29 different syllables. Four distinct syllables - a combination of trills, upsweep-trills, trill-downsweeps, or upsweep-trill-downsweeps - were especially popular and were used 69 per cent of the time.