Native bats or pekapeka are one of the few native land mammals of New Zealand, apart from seals and sea lions. Pekapeka are only found in New Zealand, from where they have been isolated from other species of bats for millennia. There are two main kinds (genera) – the long tailed bat Chalinolobus and the lesser short tailed bat Mystacina. Both kinds are endangered.
Long-tailed bats emerge at dusk, when they could be mistaken for late-flying fantails or swallows. Short-tailed bats emerge only when it is properly dark, so they are rarely seen. Pekapeka navigate and catch insects at night by boucing high -frequency sounds off their surroundings. This activity called “echolocation” gives the bats a detailed picture of their environment using sound waves rather than light.
Because of the difficulty of seeing these tiny flying animals (the size of small mice) at night, scientists have developed “automatic bat detectors”. These are small devices that pick up and record the high-frequency “echolocation calls” that the bats emit in flight. Using these “bat detectors” researchers have discovered that although pekapeka are widespread, their range has declined and they are numerous in only a few places.
Funding for the data cards and batteries for the bat recording devices is being provided to Landcare Okareka under their Biodiversity Management Plan with the Bay of Plenty Regional Council.
Pekapeka are highly mobile, with flights of 10 to 25 kms common. An individual bat will often fly over 50 km in a night and cruise to a favourite feeding site at over 60 km per hour. Because they feed over such a wide area, pekapeka need about 150 sq km of forest to sustain a colony. Just because we may not find the presence of bats at a certain location this week, does not mean to say they won't be there at a future date.
Both species depend for shelter on the oldest and largest trees in cool temperate rain forests, forming colonies in well-insulated tree-cavities to protect them from the elements. During the summer breeding season long-tailed bats change trees almost daily, females carrying their single young with them.
Long-tailed bats stick strictly to a diet of flying insects; mainly moths, midges, mosquitos and beetles. They use a membrane along the full length of their tails to scoop up insects on the wing.
And we are pleased to report that long-tailed bats have been found at a few sites around the Lake Okareka catchment. Results of this survey which will continue over summer, will be passed on to Department of Conservation for a nation-wide bat monitoring dataset.
Thanks to the Department of Conservation publication about pekapeka bats for the information for this article.
Mike and Sandra Goodwin