Eighty per cent of Britain’s butterflies have declined since the 1970s. In one summer, 9,000 garden counts found not a single one.

For most of Britain’s butterflies, the countryside stopped being home a long time ago. The meadows went under the plough, the hedgerows came out, the verges get cut in June. What is left is the back garden — the lawn, the fence, the buddleia by the shed. Not a nature reserve. A back garden.

Peacock. Small Tortoiseshell. Red Admiral. Comma. Brimstone. Names that everyone over sixty learned as a child, because they were simply there — on the Michaelmas daisies in September, on the kitchen windowsill in March, drifting over the washing on a warm afternoon. The Small Tortoiseshell, once the most ordinary butterfly in Britain, has fallen by 86 per cent since 1976.

The summer of 2024 was the one nobody could explain away. The national Big Butterfly Count recorded an average of seven butterflies per fifteen-minute count — the lowest in its history. Butterfly Conservation declared a Butterfly Emergency.

These are not impressions. These are counts.

Why the back garden became the last line of defence

Butterfly Conservation’s State of the UK’s Butterflies report found that 80 per cent of British species have decreased since the 1970s. Half of the species still left are now on the Red List — threatened or close to it. The pressures behind those numbers — lost meadows, grubbed-up hedges, tidy verges, pesticides, wetter winters — are the same pressures that have reshaped every village and every estate in the country.

Butterflies are not decoration. Where they go, the blue tits that feed their chicks on caterpillars go with them. The wildflowers that rely on them stop setting seed. The decline is not a loss of something pretty — it is a warning light. And it has been on for years.

Here is the part most people never hear: four of Britain’s best-loved butterflies do not die in autumn. The Peacock, the Small Tortoiseshell, the Comma and the Brimstone sleep through the winter as adults. From October they go looking for somewhere narrow, dark, dry and out of the wind — a hollow tree, a woodpile, the back of an old shed.

Most modern gardens have none of those left. A Peacock that finds nowhere to sleep in October does not wake up in March. That is the mechanism behind every one of those numbers.

A properly built butterfly house is the one realistic thing still left to do in an ordinary British garden — a narrow, dark, dry shelter that keeps birds out, holds its temperature and does not let the damp in.

But only if the house is actually right.

Twenty-nine summers in a Purbeck stone workshop — and what they taught her

The workshop at the bottom of Wendy Scammell’s garden was built for a stonemason, a hundred and something years ago. Purbeck stone walls, a slate roof, barely twenty square metres. A wood burner ticks in the corner. Through the one window you can see the fields running down towards the cliffs above Dancing Ledge. On the bench, a row of teardrop-shaped timber houses — some raw, some finished, narrow slots cut into the front and a little sand-filled dish at the base.

Wendy is 76. Langton Matravers, on the Isle of Purbeck, two miles inland from Swanage — the sort of village where the post office knows your handwriting. Her late husband Derek built wooden boats in Poole for forty years. The teardrop shape is his: the line of a hull, drawn upside down. “A boat sits quiet on the water because of that line,” Wendy says. “Derek said a house would sit quiet in the wind for the same reason. He was right, as it happens.”

Derek made her jigs in 1996, out of the moulds he used for planking. She has built more than 2,400 houses on them since. Every one with the same slot. Every one with the dish at the base.

She runs her thumb along a freshly sanded edge without looking up. “I’ve walked the same lane every Sunday since 1994,” she says. “April to September. Half a mile, gate to church.” She keeps the counts in school exercise books — thirty-two of them, on the shelf above the bench. In the nineties, on one August afternoon, she counted more than forty Small Tortoiseshells on the buddleia by her gate. “Last summer I didn’t see one. Not one, all year.” She puts the house down. “You notice a thing like that.”

What does not help, she knows just as well.

“People buy a butterfly house, hang it up — and nothing ever comes. It’s nearly always the house.” The slot width, for a start: too wide and it becomes a roost for sparrows and blue tits, which is the last place a sleeping butterfly wants to be; too narrow and nothing goes in at all. Or the missing dish — butterflies draw salts and minerals from damp sand, and that is not a nice extra, that is biology. Then the painted ones, smelling of varnish. “I see those bright ones in the garden centre,” Wendy says. “Lovely to look at. Empty by Christmas. Empty the year after.”

Why Wendy’s houses get used when the rest stay empty

Not principles, not philosophy — measurements, materials and mechanisms. The difference between a house that gets used and one that stays empty, worked out over twenty-nine summers. Every feature is something Wendy learned the hard way.

• “The Hull Line” Derek’s teardrop, taken from the shape of a boat. It spreads the wind evenly, so the house does not spin, does not knock against the post and puts no strain on the hanger. Wendy’s oldest house has hung from the same apple tree since 1999. Same hook, never touched.
• “The 18-Millimetre Slot” Entry slots cut a shade under twenty millimetres: wide enough for a Peacock or a Comma to crawl in with its wings folded, too narrow for a sparrow or a blue tit looking for a roost. “A millimetre out,” Wendy says, “and it’s either empty or it’s a larder.”
• “The Puddling Dish” A sand-filled dish at the base. Butterflies take minerals from damp, sandy ground — entomologists call it puddling, and for many species it is not optional. Missing from almost every butterfly house sold in Britain.
• “The Bare Timber Rule” Untreated natural timber. No stain, no varnish, no paint. A chemical smell reads as danger to a butterfly; a painted house gets passed over even when everything else about it is right.
• “The Spring-Clean Panel” The back opens without tools. Brush it out once a year in April, after the sleepers have left, top up the sand, done. Most butterfly houses cannot be opened at all — after one British winter it is mould, cobwebs and damp. This one lasts for decades.

Fifty-seven houses. Then she locks the workshop.

It started with a jar of marmalade. Two winters ago Wendy could not get the lid off, and she laughed about it. Then the saw began to wander on the last millimetre of a slot. The hand surgeon at Poole Hospital was kind and very clear: arthritis at the base of both thumbs, and it only goes one way. “The saw still goes where I tell it,” Wendy says. “The last millimetre doesn’t. And the last millimetre is the whole job.”

Derek died two years ago. Their son Martin has finished the annexe at his house in Shrewsbury, and Wendy moves in November. Her granddaughter Ellie is nine and already counts butterflies with her over the phone on Sunday evenings.

What she is leaving cannot be packed. The smell of fresh-cut timber on a cold Purbeck morning with the sea mist still lying in the fields. The hour in the workshop before breakfast, the wood burner just catching. Derek’s jigs, worn smooth where his hands held them. She never thought of those mornings as precious. Not until she started counting the ones she had left.

Fifty-seven houses are left on the bench. None will be made again. Nobody else knows the slot calibration. Nobody else has Derek’s jigs — and they are not going to Shrewsbury. When the last box goes out, the workshop is finished. Not retired. Finished.

Whoever takes one now takes the last thing to come out of that workshop. That is not a sales line. It is simply what is true.

Why she is letting the last of them go — and what she hopes for

Once it was clear the workshop was closing, the question was simple: what happens to the fifty-seven houses still on the bench? Martin’s annexe has no room for them. Giving them away one by one at the church fete was never going to get them where they were needed.

Martin put her in touch with Backroad Goods — a small shop that carries handmade nature pieces and deals with the posting and packing. The price was Wendy’s decision. Not a collector’s price, not a premium for being the last. A price for somebody with an actual garden who is actually going to hang one up.

“I made them so butterflies would sleep in them,” she says. “Not so they’d sit on a shelf in somebody’s hallway.”

Money was never why she built them. It is not why she is selling them now. What she wants is smaller than that and harder: a Brimstone on somebody’s primroses next March. A Small Tortoiseshell on somebody’s buddleia next August. No grand plan. Just the hope that the work goes on in other people’s gardens once her hands have stopped.

What Wendy’s customers are saying

Before they are gone — what you need to know

Autumn is the window. The butterflies that sleep through a British winter are choosing where to sleep right now.
What is still on Wendy’s bench is all there is.

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