Female lesser short-tailed bats judge males on their songs
The New Zealand lesser short-tailed bat is an unusual creature. It’s a small species endemic to the islands of New Zealand, and spends a lot of its time foraging on the ground, but it’s the courtship that really makes this bat notable.
Lesser short-tailed bats are one of just two species where males congregate to compete with each other and woo females. This behaviour, known as lekking, takes place in the trees at night as males take up ‘singing roosts’ around their communal daytime roosting tree. From their nooks, contestants in this moonlit talent contest perform their best songs for six hours in the hopes of attracting females as they fly past.
Scientists analysed the calls of male lesser short-tailed bats and found that they fill their love songs with trills and sweeps between high and low pitches. Their repertoires are wide, and certain sounds were found to be more popular with females. One particular call, a combination of a trill and a downward sweep, was found to be shorter when produced by large males, so females are able pick out the biggest, strongest suitors just by listening.
Image: Biodiversity Heritage Library/flickr