“The bats are going, and it isn’t a mystery. They’ve got nowhere left to sleep.”
“The bats are going, and it isn’t a mystery. They’ve got nowhere left to sleep.”
Why a seventy-one-year-old entomologist from north-east Victoria is selling off his last hand-built bat boxes — before his hand gives out.
Last light outside Chiltern, north-east Victoria. Nev Tarrant has sat on this dam bank every January since 1987, writing down what comes to his light — and what stopped coming.
It’s the first warm night in November. By half past eight the candle has done nothing, somebody has gone in for the spray, and the best hour of the evening is over. Twenty years ago there would have been bats over that lawn, and nobody would have needed the spray at all.
A Gould’s wattled bat weighs about fourteen grams. It comes out just after sunset and works the air a few metres above the lawn. In one night it takes up to a thousand mosquito-sized insects. Most people who have one over the back yard have never noticed it.
It is not just the biters. The same bat works the whole block after dark: moths, midges, gnats, the beetles whose grubs get into the veggie patch. Australia has around seventy species of insect-eating microbat. One small colony clears tens of thousands of insects a night, for nothing.
- Up to 1,000 mosquito-sized insects taken in a single night.
- About fourteen grams — the whole animal weighs less than three twenty-cent pieces.
- Out shortly after sunset — hunting every night through the warm months.
- Garden pests as well — moths and beetles whose larvae go through the vegetables.
- No spray, no cost, no noise — and it only ever asks for somewhere to sleep.
Somewhere to sleep is the whole problem. In Australia that does not mean a cave. It means a hollow in an old eucalypt, and the numbers on those are worse than most people think.
The man who can tell you how far it has gone spent forty years writing it down, one night at a time, on the same dam bank.
Every hollow they sleep in is older than the town you live in
A microbat climbs into the open bottom. It is the only way in, and the same way they go up into a hollow.
This is the fact that changes everything. Australia’s microbats do not live in caves. They live in hollows, in old trees, almost always eucalypts.
And a hollow is not a hole. It is a crack behind a limb that has been rotting out quietly for generations. A eucalypt needs about a hundred years to make even a small one, and a hundred and fifty to two hundred and fifty years to make one a bat can use.
Three hundred and four vertebrate species in this country need them. About a hundred are now rare, threatened or near-threatened, and losing the old hollow-bearing trees is a big part of why.
The old trees went, and they are still going
Three stags left, and stumps to the horizon. Every one of those was somewhere a bat used to sleep.
The goldfields took the first wave out of the box-ironbark country. Firewood took the second. Paddocks took the third. And it has not stopped: about half a million hectares are cleared in Australia every year. New South Wales alone cleared 66,498 hectares in 2023, up forty per cent in twelve months.
Planting does not fix it either. Plenty of people have spent their retirements putting trees back. But a tree planted this winter will not carry a usable hollow until around 2180. Nobody alive today will see those hollows come back.
“The bats are going, and it isn’t a mystery. They’ve got nowhere left to sleep.”
And the food went at the same time
Nev Tarrant has his own record of that, and it is not a guess. Same white sheet, same dam bank, same lamp, second week of every January since 1987. He counts moth species.
“Eighty-seven: a hundred and eighty-six species off one sheet in one night. You couldn’t keep up.” He turns the page. “Two thousand and six: ninety-four. This January: thirty-one, and I sat out there four hours to get them.”
Nowhere to sleep, and less to eat. That is the Australian version of this problem. Only one half of it can be fixed inside a lifetime.
The boxes that cook the animal they were bought for
Rough bark to climb, and timber thick enough to hold its temperature through a February afternoon.
Search for a bat box in Australia and you will find hundreds of thin, flat, mass-produced ones, mostly out of the same few factories. They photograph well. Nev has put temperature loggers inside them. He can name five reasons they fail without looking up from the bench.
The part Nev takes personally is not the factories. It is who buys them.
“Somebody buys a box because they want to help, and in the worst week of the summer it does the opposite of what they paid for. That’s the bit I can’t wear. They meant it.”
The man who spent forty years writing down what was disappearing
The shed used to be a dairy. Behind him: forty drawers of moths he built himself in the eighties.
Neville Tarrant is seventy-one. Everybody calls him Nev. He lives on eleven acres outside Chiltern, in the box-ironbark country of north-east Victoria, with a dam at the bottom of the block and a shed that used to be a dairy.
He spent thirty-eight years as an entomologist with the Victorian agriculture department. Pest moths, mostly. He is precise in a way that is slightly funny: he gives you the Latin name, apologises for it, then gives it to you again ten minutes later.
The private half of his life started in January 1987. A white cotton sheet between two posts on the dam bank, a lamp in front of it. “You do it the same way every time or you haven’t got a record,” he says.
And for forty summers, something else came to the sheet.
“They work the edge of the light. You don’t see them so much as feel the air go. Every minute or so there’s a snap. That’s a moth gone. Chalinolobus gouldii, mostly. Gould’s wattled bat.” He stops. “For thirty years I thought of them as a nuisance. They were eating my data.”
The shed tells you the rest. Against one wall stands the cabinet: forty shallow drawers of moths he built himself in the eighties, every drawer rebated and felt-sealed so nothing could get in at the specimens.
“A drawer that leaks is a drawer full of dermestid beetles and forty years of work turned to dust.” He runs a thumb along a joint without thinking about it. “A gap is either right or it’s wrong. There’s no roughly.”
That is the hand that now makes the boxes, on the same bench, to the same tolerance.
What forty years of sealed drawers builds into a bat box
Fallen yellow box and red ironbark, nothing on it at all. The weight is the feature.
Nev will not sell you a list of qualities. He will sell you six decisions, and he can tell you the reason for every one.
The graph he kept for forty years and never once looked at
Second week of January, same spot, since 1987. Forty notebooks, never once laid side by side.
Forty notebooks. Forty summers. And in forty years Nev never once laid them out next to each other.
That was Ruby. She is nineteen, first year environmental science at La Trobe in Bendigo, and in February she asked whether she could use her grandfather’s records for a unit assignment. He handed her the lot in a wine box.
“She had them in a spreadsheet in an afternoon. Then she turned the laptop round.”
One line. 1987 on the left, 2026 on the right, going down the whole way.
“I’d been living inside it one night at a time. Forty times I wrote a number in a book, and every time it was just that night’s number. Bad weather, wrong moon. You always have a reason.” He is quiet for a second. “You don’t see a slope from inside it.”
Then the second thing, the one that actually put him in the shed. He thought about the bats, and he went out that night and stood at the sheet and waited for the snap.
“Nothing came. Thirty-one species on the sheet, and nothing came for them.”
He is careful about what a box can and cannot do, and this is the sentence the whole thing turns on.
“A box doesn’t bring the moths back. I’ve got forty notebooks that say nothing does, not quickly.” He sets it down on the bench. “But there’s no sense in the insects coming back to a district with nowhere to sleep. One of those takes a hundred and fifty years. The other takes me two days and a length of ironbark.”
Why these sixty-one are the last
Emergence, just after sunset. The tolerance, the mass, the forty-degree margin — all of it is for this one minute.
Nev has essential tremor in his right hand. It has been getting slowly worse since about 2016.
It took the pinning first. Setting a moth is work at a quarter of a millimetre — the pin goes through the thorax square, the wings come forward on the board, the antennae are laid.
“I pinned my last one in 2019. Big hairy thing, off the sheet. The pin went through off-centre.” He says it the way you would read out a measurement. “I looked at it under the glass, put the setting board in the drawer, and that was that. You don’t argue with it.”
The boxes lasted longer, because a box is bigger work than a pin. But the entry slot is not bigger work.
“The boring is the same problem. You’ve got to hold it dead level through fifty millimetres of ironbark. A quarter of an inch out and you haven’t made a roost, you’ve made a trap.” He flattens the hand on the bench and it does not stay flat. “It goes at the end of the cut now. And I can feel it go.”
There is nobody behind him. His daughter Robyn is a radiographer in Wodonga. “I’m the last one in this shed.”
What is left is stacked along the wall under the cabinet: sixty-one finished boxes. When they are gone, there are no more.
“I want them on sheds, not in a catalogue”
Sixty-one left against the shed wall. He priced them low on purpose.
“Two days and a length of fallen ironbark. Somebody in Melbourne would put two hundred and twenty on that and they’d be right to.” He shrugs. “But that box sits in a catalogue. A cheap one goes on the back of somebody’s shed. I want them on sheds.”
The low price is not a clearance. It is the whole point of the exercise, and it has a date attached to it.
Australian microbats carry pups from about November. A box that goes up in spring gets found and settled before it matters. One that goes up in January is an ornament until next year.
And what he actually wants is smaller and more exact than saving anything.
“One female. One pup. In a wall thick enough that the February heat never gets to her. That’s the whole ambition.”
He adds, almost as an afterthought, that whoever puts it up gets a thousand mosquito-sized insects a night out of the deal. But that is not why he is doing it.
He is quiet for a moment, and then says the only sentence in three hours that gives anything away.
“I’ve got a very good record of it going down. I’d like to be some small part of the record of it going back up, and I’m aware I’ve left it a bit late.”
What people are saying about Nev’s boxes
Before you decide
Nev will not build another stack of these. The females shut out of the old trees are looking right now, in spring, for somewhere dry and cool to raise what comes next. Not in January. Now.