Buzzing about bats

Long-tailed bats (pekapeka) have recently been found in suburban Auckland and, fortunately for these threatened creatures, Aucklanders are bat mad.

By Mandy Herrick

Long tailed bat, Colin O'Donnell

Long tailed bat, Colin O'Donnell

Ben Paris, aka Batman, has been charged with creating a little bat fever, so he takes me to the semi-industrial site where it all began, a handkerchief of grass overlooking
native bush.

Here in Swanson Reserve, 20 minutes from Auckland City, long-tailed bats were discovered last year, and a Bat Fun Day was held to welcome these furry thumb-sized citizens into the neighbourhood.

“We thought that we would get 50 people. Instead over 400 people turned up. This place was humming. We had bat face-painting, bat kite-making and lots of stalls and
displays telling people about how they could care for their new neighbours,” he says.

Ben is Auckland Council’s senior biodiversity officer and, among the 30 ecologists who work at the council, he has found his niche as bat protector. He hosts a Batman Facebook page, gives talks and bat walks, attends conferences and organises suites of bat hotels.

So far, bats have been found in two suburban areas in Auckland – Henderson Valley and Swanson Reserve.

Ben Paris aka Batman

Ben Paris aka Batman

We strain our necks and look up at an old pine supporting two home-made wooden “kent boxes” which are in the bats’ flight-line four to five metres up.

“In Geraldine, they took three years to move in, so we’re not holding our breath. Arborists check them every few months and apparently a few spiders have taken up residency there.”

These boxes are a snug fit for the bats and the tree is ringed with a possum guard, so it is hoped predators will stay away from the roosts.

Typically, long-tailed bats move between roost sites regularly (the pups hang on to their mothers by their nipples) so once these key sites are identified, reinforced predator control for ship rats, possums, stoats and feral cats can be put in place.

The bats can’t be tracked for long distances by radio tracking systems because they’re too small to carry large battery devices, so finding the roosts, or getting them to move into safe bat hotels, can be hit or miss.

It’s this experimental new territory that Ben seems toenjoy; he’s veritably buzzing with new ideas about all things bat related.

He wants to start a citizen science bat map, enlist primary schools to make bat hotels and have whole neighbourhoods erecting backyard, predator-proof, pole-mount boxes.

The Swanson Reserve lies along the North-West Wildlink, a 40-kilometre wildlife corridor of backyard sanctuaries, so no doubt his ideas will be well received in these parts.

Forest & Bird has been actively working with homeowners in the area to protect their patch, and join the green dots between Tiritiri Matangi to the Ark in the Park in the Waitäkere Ranges, so birds, insects and bats can spill out from these wildlife havens.

In this belt lie 176 households that regularly carry out pest control in their backyards, so it’ll be easy work finding the bat lovers. Or if that fails, there are always mosquito haters.

“In the US, people have these bat boxes stuck to the side of their houses as an insect control device. One bat will gobble up to 1000 mosquitoes in a night, so they’re pretty
handy to have around,” he says.

Unlike US and Australian bats that check into bat boxes overnight, New Zealand bats are more elusive.

Long-tailed bats typically have three real-estate requirements: a big gnarly tree with loose bark for roosting, a corridor of water that acts as a flight path and open areas to
feed on insects such as golf courses, school fields and parks.

Like many Aucklanders, bats are feeling the squeeze of the housing shortage. Hole-riddled gnarly püriri trees or big, old kauri are becoming harder and harder to find.

And though they’ve adapted to take up residence in pine, macrocarpa, gum trees and willows, kauri dieback and dismantling of tree protection laws under the Resource
Management Act are threatening their existence.

Fortunately, one of the best spots to get a glimpse of these creatures is in the 2100-hectare pest-controlled Forest & Bird-Auckland Council Ark in the Park, in the Waitäkere Ranges.

So as the light begins to fade, we leap into our cars, drive 15 minutes up windy, gravel roads and reach a clearing where flocks of bats are known to come alive at twilight.

I clutch a bat detector – one of 10 the council owns – that can be lent to anyone who suspects bats may be hiding out in their garden or neighbourhood reserve.

I set the dial to 40 kilohertz, and wait patiently for my bat detector to click and buzz to alert me to the fact that bats are within 20 metres.

Nothing happens. I wait. Still nothing happens. I arch my head back and look into the gloaming for the black-winged figures with their staccato, erratic flight patterns.

I’m told these minuscule bats, which weigh less than a couple of 20-cent coins, can fly 25 kilometres in one night.

Impatient, I ask Ben what they’ll be doing on this chilly mid-November evening. “The temperature is sitting at 11 degrees, so they might be out and about. If it drops below
10 degrees, they’ll go into a state of torpor so they’ll be especially drowsy.”

Although this built-in energy-saving device can work well, it also puts the bats at the mercy of predators. And it’s not just predators. Unwitting arborists can also fell whole roosts of dozy bats, causing them to spill out of their warm burrows, get cold and die.

Arborists have been very receptive to Ben’s messages, and, because arborists spend their lives suspended in trees, they are the most likely to spot a bat roost.

Despite all these initiatives, I can’t help thinking that these bats have the odds stacked against them. The Department of Conservation estimates long-tailed bat numbers will fall by about 90 per cent by 2050, so time is of the essence.

Ben and his bat colleagues have successfully installed about 20 bat boxes in Hamilton and bat love down there has reached fever pitch, so it may catch on in a big way.

Ben is even hatching a plan with a team of bat researchers to transfer some of the bats’ rarer cousins, lesser short-tailed bats, however, a bat translocation has never been successful because of their hard-wired homing instinct and their ability
to fly over long distances.

If such a plan succeeded, it could open up a whole new swathe of bat territories – and help
spawn more bat-care groups.

As we scan the night sky, disappointment slowly replaces excitement. The bats are not coming out. Ben says perhaps it’s too cold or the moon is too full, making them easy prey
for ruru.

Bat-spotting season starts in earnest in January when it’s warm, so I eagerly sign up for one of the park ranger summer bat walks at Ark in the Park. The early symptoms of bat fever are evident.