A warm home for our garden birds
A warm home for our garden birds: why this small alpaca heart is turning up in gardens across New Zealand
Right now, from Northland to Southland, garden birds are building nests. Most people put out seed, fat balls or a bird bath to help them. But in October and November something else decides how many chicks make it — and almost nobody thinks about it. Not what the birds eat. What their nest is made of.
The quiet danger a bird feeder can’t fix
A feeder helps birds eat. It does nothing in the weeks before the eggs are laid, when a pair of birds is searching for something soft to line the nest with. In a tidy New Zealand garden, that search often fails.
The soft, loose things birds used to build with are mostly gone. Lawns are mown, garden beds are mulched, hedges are trimmed. What birds find instead is orange baling twine, torn bale wrap, netting from the feijoa and citrus trees, and shade cloth that frays into thin plastic threads. Birds can’t tell the difference. They take what they find.
And that is the problem. Plastic thread doesn’t soften in a nest and it doesn’t rot away. A thin strand can wrap around a chick’s leg or neck and pull tighter instead of letting go. Bird rescuers call it fibre entanglement. It happens every season, and most people who feed birds have never heard of it.
“Every spring we get chicks brought in with plastic thread wound around a leg or a wing. Nearly always it came from nesting material the parents picked up in a garden nearby. Natural fibre like alpaca wool squashes down and breaks down safely. Plastic does neither. It really is that simple.”
Dr Fiona Marsden, PhD Avian Ecologist & Bird Rehabilitator · Kōwhai Gully Bird Rescue, MastertonWhat birds are actually looking for — and it was never string
Left to themselves, many small birds don’t line their nests with grass. They line them with animal hair and wool. Whatever they can pull off a fence, a hedge or the ground under a paddock. Wool holds warmth, dries quickly after rain and lies soft around a chick.
The riroriro, or grey warbler, is one of the most common native birds in New Zealand gardens. It builds a small hanging nest shaped like a pear, with a door on the side. Inside, it lines the nest with wool, hair or feathers. Anyone who grew up on a farm has seen the little tufts of wool on the barbed wire — and the birds that come to take them.
That wool has quietly gone missing from most gardens. Fewer paddocks nearby, tidier sections, everything swept up. The birds still go looking for it every spring. Most of them don’t find it.
Which is the whole reason a retired wool classer in the Wairarapa started hanging wool on a fence post.
Near Carterton, Wairarapa, October. The Tararua Ranges sit along the western sky. A nor’wester pushes over the tops and shakes the old kōwhai by the road. Heather Prebble stands at her kitchen window with a cup of tea, the way she has every morning since she left the shearing sheds.
For 31 years she sorted fleeces on the wool table. Fine from strong, long from short, clean from dirty. Thousands of fleeces every season. She can tell one wool from another with her eyes closed. But it was a bird, not a fleece, that taught her the most.
The morning a grey warbler stripped her fence bare
Heather came to alpacas late. In 2012 she bought four hectares near Carterton and, for the first time in her life, got animals she never had to sell: alpacas. There are nine of them now.
In September 2018, after the shearing, she noticed tufts of alpaca wool caught on the barbed wire where the animals rub. Then she noticed a grey warbler, hardly bigger than her thumb, tugging at one of them. It flew into the kōwhai with a cream-coloured tuft in its beak.
It came back. And again. For three weeks. By the end, ten metres of fence wire were picked clean.
“Thirty-one years I read wool for a living. It took a bird the size of my thumb to show me what it’s actually for.”
So Heather cut a heart out of the leftover wire netting from the hen run. She packed it with wool from her old sorting table and hung it on the post under the kōwhai with a piece of old chain. “A barbed wire fence is no place for a bird that small,” she says.
She sorted the wool the way she always had: four colours, never dyed. Dark brown, cream, caramel and charcoal. An old wool classer’s habit. She still packs every heart the same way.
The nest in the kōwhai was lined with her own paddock
Within two weeks the heart was almost empty.
Heather watched from the kitchen window. Trip after trip from the post to the kōwhai. Then one morning she saw it: a small hanging nest, shaped like a pear, swinging from a thin branch.
Moss and cobweb on the outside. And through the little side door, a lining of soft cream wool from her own alpacas.
That summer the grey warblers raised their chicks in it.
Heather spent six years quietly fixing a problem most New Zealand gardeners don’t know they have. Her hearts are still available — but only from the last shearing she sorted herself.
See Heather’s Nesting Heart →The one thing birds search for every spring — and almost never find
For a nesting bird, alpaca wool is different in every way that matters:
- It keeps eggs warm — alpaca fibre is hollow inside, so it holds heat well. A nest lined with it stays warm through a cold spring night in the Wairarapa, when the eggs and newly hatched chicks need it most.
- Nothing added — alpaca wool has no lanolin, the greasy coating on sheep’s wool. It is clean and soft against a chick from its first day.
- Safe in the nest — plastic thread stays stiff. Alpaca wool squashes down and breaks down on its own. It doesn’t form loops a chick can get caught in.
- Soft enough for the inside — birds build the outside of a nest from rougher material and line the inside with the softest thing they can find. Alpaca wool is at the top of that list. That’s why the grey warblers went for Heather’s fence.
- Stays dry — alpaca wool sheds water, so the lining stays dry through spring showers instead of turning into a cold, wet mat.
“Nobody has to explain any of this to the birds,” Heather says. “The first heart I hung out had a grey warbler on it the same morning.”
“The neighbours started asking. Then the garden club.”
After that first spring, Heather made more. One went on the post by the letterbox. One in the old plum tree. One on the corner of the hay shed.
By November there were more nests around the place than she had ever seen. Grey warblers, silvereyes, a pair of fantails that had never bothered with her garden before.
Then the neighbours noticed. Then they asked. Then the Carterton garden club asked.
“I gave them away for six years,” Heather laughs. “It never crossed my mind to sell them. I had nine alpacas and a roll of hen netting. It just seemed the obvious thing to do.”
It was her granddaughter Mia, a nurse in Palmerston North, who finally set up the shop. “She did it on her phone at my kitchen table,” Heather says. “I didn’t even know until she showed me the first order.”
“I’d rather the riroriro had it than the wool buyer.”
For 31 years Heather’s hands did the hardest kind of fine work there is in a shearing shed. Now they have rheumatoid arthritis. Her knuckles are swollen. Some mornings, she says, she can’t do up a button.
Each heart takes about forty minutes of pulling, sorting and packing the wool into the small wire holes. Her hands can’t do that any more. The alpacas are staying on the farm. But from now on their wool will be sold, not made into hearts.
The last shearing she sorted herself was in November 2025. There are 186 hearts left from it. When they are gone, there won’t be more.
“People ask if I’m sad about it,” Heather says. “I’m not, really. I had a good run. I just want the last ones to go to people who will hang them outside.”
This is what customers said about it.
🍃“Hung it on the back fence and within four days a grey warbler was coming every morning. I’ve had a feeder out there for years and never seen birds so busy. My grandson checks it before school.”
🍃“I’d never thought about nesting material at all. Once I read about the netting, I kept seeing bits of it all over my own garden. Put the heart in the lemon tree and by the end of the week the silvereyes were pulling at it. It looks lovely too.”
🍃“Bought two — one for me, one for Mum, who is the real bird lover. She went quiet when I told her about Heather. The wool is nothing like what you get at the garden centre. You can tell a real person made these.”
Heather’s Alpaca Nesting Heart
Hand-cut wire-mesh frame · Four undyed wool colours · Refillable · Hangs from a chain
From the last shearing Heather sorted herself · 186 left · Limited quantity
* This is a sponsored story. Product available while stocks last. All alpaca wool is from Heather Prebble’s herd near Carterton, Wairarapa.