Although a 10-week hunt turned up no sign of the long-tailed bat, known as Chalinolobus tuberculatus, Lincoln University summer scholar Karina Hadden says a few could be present on the peninsula.
“Not finding bats doesn’t necessarily mean they’re not there, but if present, they would most likely be in small numbers. There’s probably not a sustainable population or chances are, we would have found some.”
The long-tailed bat was last recorded on Banks Peninsula in 1963 and a 1990s survey failed to locate any of the tiny animals, which are about the size of mice.
However, the isolated geography of the area makes the species a good candidate for a remnant population and some recent unconfirmed sightings by members of the public prompted this new search.
The project, funded by the Christchurch City Council and supported by the Department of Conservation and the Banks Peninsula Conservation Trust (BPCT), involved Karina placing 50 acoustic recorders in various bat-friendly areas and later analysing the results.
The recorders were programmed to detect “bat-like” calls, which would be verified by bat specialists.
In spite of a fruitless search this time around, Karina says another bat survey should be carried out in 10 to 20 years’ time, as recovery of old forest growth takes decades.
The Chalinolobus tuberculatus flies very quickly and can seem to flit like a bird or large moth when seen from a distance.
“They need protection from predators such as rats, possums, stoats and cats, so if there were any long-tailed bats in the area, we would want to take conservation measures,” Karina says.
The nearest and only confirmed population in Canterbury exists on the east coast of the South Island near Pleasant Point and predator control has been instigated to try to preserve them.
Karina says nature could be given a helping hand on Banks Peninsula by protecting cabbage trees, willows, and other large trees, which form thermally stable holes suitable for bat roosting, as well as for small native owls called morepork.
The BPCT is running a project to determine the distribution of morepork in the area, and to assist with this, Karina placed different monitors in various areas during the bat survey to hunt for the small owl.
“Bats were the main focus of the project, but we did find morepork in at least one new location,” she says.
Although morepork are widespread in many parts of New Zealand, they are not so common on Banks Peninsula.
The trust is also working to improve morepork habitat in the area, which has involved putting 75 roost boxes into BPCT covenants. The boxes were made with the help of volunteers, including the Akaroa Men's Shed.
The introduced species, little owl, also use the roosts.
Karina’s supervisor, Lincoln University Ecology Tutor Mike Bowie, says the recent potential bat sightings in Banks Peninsula were mostly around lights that attract insects.
“It’s possible that little owls or morepork feeding on insects were mistaken for bats.”
He says protecting existing native remnants on private land is extremely important to conserve precious species such as these.
“The Banks Peninsula Conservation Trust is doing a stellar job in making this happen through covenants and pest control work.”
If you think you may have sighted a long-tailed bat on Banks Peninsula, contact Department of Conservation Technical Advisor Moira Pryde at email@example.com. Include the date of the sighting, time of day and GPS location.
If you would like to build and install a morepork roost, email Alison Evans at firstname.lastname@example.org.
PHOTO: COLIN O'DONNELL, DEPARTMENT OF CONSERVATION