Batty about bats

21:51, Jun 13 2012

One of the phrases that I use all the time is that New Zealand is the "land without teeth" (I pinched that soundbite from Professor David Bellamy who used it when making "Moa's Ark"  twenty years ago).

We say "land without teeth" because New Zealand has no native land mammals. Except of course, that creature of the night, the bat.  We have two native species of bat in New Zealand, the long-tailed and the short-tailed bat.  We had another species - the greater short-tailed bat, but we lost that after a rat plague on Big South Cape Island in Southland.

Both species of bats are endangered, but the long-tailed bats are more common. They're the ones you may have been lucky enough to see at dusk, swooping out from some willows perhaps, or flitting past in the moonlight.  The short-tailed bats are ancient and very mysterious, only appearing under the cover of darkness. Short-tailed bats are from a different family of bats, and the last remaining species of that kind.

Short-tailed bats are amazing because instead of heading to the sky to feed on insects like most bats around the world (including the long-tailed bats), they swoop out of their colonies at night, fly DOWN to the ground, fold up their wings, and scrabble around on the forest floor on their elbows, eating nectar, invertebrates and fruit. Bizarre bat behaviour indeed, unless of course you evolved in New Zealand, the land without teeth, without native rodents, and therefore the forest floor provides a veritable smorgasbord of culinary delights.

What's also cool about these bats is that despite the fact that they are tiny (like mouse-sized, can fit in the palm of your hand), they fly a long way.  Individual bats can easily travel 50kms in a night, which doesn't take them too long, since they fly at around 60km/h. All of this travel, and regularly shifting colonies means bats actually need quite a lot of forest to survive. At least 150 square kilometres.  Habitat is hugely important to bats. So too is being safe from predators.

Holy bat-crimes batman!

...Is probably what the poor DOC ranger thought when she saw the scattered short-tailed bat wings around an ancient tree(nicknamed "the mothership") in a forest near Ruapehu on visiting the colony in March 2010.  Over the course of the week, an unknown assailant had repeatedly raided the colony eventually killing 102 of our native and endangered short-tailed bats.  After some excellent post-mortem CSI skills of Massey, they discovered a single cat was the culprit.  That story epitomises the fact that predators are having a huge impact on our native wildlife, not just our vulnerable birds, but also our only land mammals. So bats are yet another reason we need to keep on top of predators. What about you guys? Have you ever seen one of our native bats? where was it? what did you think?