Fascinating Facts About Native Bats

Forest and Bird, Volume 20, Issue 3, 1 August 1989, Page 5

Fascinating Facts About Native Bats

he fact that the endangered kakapo is a lek species has been known for sometime — but scientists have now discovered that the short-tailed bat is another lek species. Lek behaviour refers to the practise of male animals — insects, fish, frogs, birds and mammals — congregating together in traditional sites where they calf and display to females. DSIR Ecology Division researcher Mike Daniel recently went to Codfish Island, the 1500-ha reserve km northwest of Stewart Island, to observe the bizarre mating ritual of the short-tailed bat. That and the long-tailed bat are our only native mammals. ; On Codfish Island — incidentally the island where the kakapo is at its most numerous — the bats fight for small holes in trees. From these they ‘sing’ for up to 10 hours a night for 10 to 12 weeks in what is considered a pretty exhausting exercise and one that places them at risk from predators. People can hear the high-pitched pulsating warble for over a distance of 50 metres. Each night female bats visit the traditional holes to mate. However, most of the males fail to attract a female, a feature common to all lek species. Scientists do not know whether the female is attracted by a vigorous display or whether the location of the tree is the key. A further unexplained feature of

short-tailed bat breeding is that the young are born in the middle of winter, six months later than bats in North Island kauri forest which do not have a lek system. They are born without fur and at a time when there is little food — factors scarcely conducive to survival of the species!

In other ways the short-tailed bat is unusual. Although it can fly 20-30 kms per night, it in fact spends a lot of its time scuttling up and down tree trunks or into seabird burrows. They eat flying insects, insects on the ground, fruit, pollen and nectar. pe