Good news for Gotham

He wears a mask. He works by night. He uses high-tech gadgets and calls himself… dramatic pause… NZ batman!

Admittedly the mask is a rather silly one, and it’s not so much for striking fear in Gotham’s criminals as inspiring laughter and learning in Auckland school kids – yet there is a serious side to Ben Paris’ work.

The senior biodiversity advisor for Auckland Council has spent hours setting up sonar detectors that can pick up the high-pitched calls made by native bats, and he’s made an important discovery.

These mysterious, tiny and endangered creatures are living in three previously unknown populations around the fringes of Auckland – in one case in its suburbs – with bats visible at dusk just half an hour’s drive from Queen Street.

The discovery has come as a surprise to many, who believed New Zealand’s bats only lived in our oldest native forests, and now a second survey is underway, in 42 locations around the Auckland area, to learn as much as possible about these amazing creatures, and how they can be protected.

We have bats?!

Few people realise New Zealand has native bats, yet we were once home to three species. One has already been wiped out (the last was seen in 1967), while the lesser short-tailed bat survives in small populations and is listed by the Department of Conservation as a “species of highest conservation priority”. Their relatives, the long-tailed bats, are doing slightly better: they are endangered, though more widespread.

Known by Maori as pekapeka, bats are this country’s only native land mammals (though air mammal might be a more appropriate phrase). Short-tailed bats eat fruit, insects, nectar and pollen and have a weird habit of crawling around on the forest floor using their wings as legs – a dangerous practice that leaves them exposed to predators such as feral cats, rats and stoats and partly explains their low numbers. Long-tailed bats on the other hand are purely insect-eaters. They catch their prey in flight and are even tinier than short-tails, weighing just 8-14 grams.

Both varieties like to sleep during the day in old hollow trees or under big pieces of bark that have partly peeled off. This too explains why they are so at risk. Mark Bellingham, the North Island conservation manager for Forest & Bird, says that the ideal home for a bat is a craggy native tree that’s 300-400 years old. Thanks to our history of aggressive logging of native trees, very little of this kind of forest survives in New Zealand and much of our native bush is just 50 or 60 years old.

Holy suburban populations, Batman

Knowing bats need these old trees as roosts meant it was a surprise to find three extra populations so close to Auckland central. The bats found in Ben’s survey are long-tails, and they’re living in Pakiri, suburban Swanson, and Riverhead forest.

It’s thought they have adapted to the lack of ancient native trees by making their homes in exotic replacements such as gum trees, poplars or pines, with the bats in Riverhead seeming particularly unlikely. After all, Riverhead forest is a pine plantation – an artificial environment managed by forestry company Rayonier NZ Matariki Forests.

“It’s quite amazing that they can survive in these modified environments with big crop rotations,” says Ben. “We really don’t know yet how they’re surviving in there.”

The discovery could have set up a classic conflict between the corporate loggers and the vulnerable bats, yet Ben says the forest managers have been great. “After the survey, we approached Rayonier and they’re been very supportive of any conservation measures.” The company has now teamed up with Ben’s Auckland Council team and Auckland University to help work out how the bats have beaten the chainsaws.

What can be done?

It’s possible that old dead pines missed by the loggers are being used by the bats, in which case Ben is hopeful that Rayonier will be able to leave these trees intact. After all a rotten pine isn’t much good for milling, yet can be home sweet home for a night-flier. Another option is installing artificial bat roosts, but this is considered tricky – bats have been enticed into roosts before but it took three years before they moved in, and no-one really knows why.

Either way it’s clear that lots of research, field work and experimenting needs to be done. Ben is busy with his second, more extensive, survey and in the meantime, both he and Mark from Forest & Bird are encouraging the public to get involved.

As “NZ Batman” Ben co-ordinated a bat fun day in Swanson Reserve in March to teach kids about their winged friends. The message on the day was that anyone who sees a bat should report it to Auckland Council by calling (09) 301 0101. You can also get a free loan of a bat detector from the Council which is a “really awesome experience, especially for kids”, says Ben – and anyone who suspects they’re lucky enough to have bats on their land should likewise borrow a detector, let Council know, and make an effort to kill any nearby rats.

Oh, and everybody should think twice about cutting down big old trees. After all, it could be handy to have more bats around, says Ben. They snack on pests such as mosquitoes, while research in the US on similar micro-bat species is looking at their ability to control insects such as codling moths, which damage valuable apple crops.

Ultimately there’s no reason why bats shouldn’t return to places like downtown Auckland, bringing a touch of Gotham to our cities as they head out on their night-time anti-mosquito raids. It would be a triumph of conservation – and co-operation with business – and that’s something that would really make NZ Batman smile.

Where can I see a bat?

Aucklanders keen to spot a bat should visit the Cascades walk in the northern Waitakere Ranges during the summer. Says Mark Bellingham of Forest & Bird: “Just put on mosquito repellent and lie down in the grassy area near the car park. You’ll see them at dusk hunting for insects. People go down for a BBQ and they’re like ‘hello what’s that!? It’s not a morepork, it’s a bat!’”

There are also known populations on the outskirts of Hamilton (visit www.tinyurl.com/bdghhja for a cool map showing bat locations around Hamilton), Nelson, and around the Canterbury towns of Geraldine and Timaru. Bats are most likely to be seen at dusk in areas with mature trees, on the edge of an open area, or near a stream, lake or river.

Mainlanders at risk

Bats were once common in Dunedin, Invercargill and Christchurch, where they roosted under the wooden bridges across the Avon River until 1885. However DoC says recent surveys show South Island long-tailed bats are now rarer than previously thought and efforts are underway to preserve their numbers.

Anyone can be batty!

• Think twice before you cut down that big old tree
• Look out for bats flying just on dusk around open areas near waterways.
• Call your council, DoC or Forest & Bird if you see one, and borrow a bat detector!

Got a great conservation story? Email [email protected].

Image captions (Tracy)

Over seven days this lone feral cat killed 102 short-tailed bats near Ohakune when it discovered a roosting tree. The picture shows some of the dead bats and the remains of their wings next to their killer. The cat was eventually found and destroyed by DoC staff.