It's hard to describe the exact sound made by four giant swans playing rubber powered trumpets.
But feed a herd of flatulent ducks a barrel load of sprouts and shove them in a tin room together and you can start to get the gist.
For the past few weeks, four large trumpet playing swans and their slightly eccentric conductor have been mysteriously waddling up to places across Glasgow, serenading the local public with loud blorts and blurps from their specially constructed brass instruments.
After a tip off from the public about their most recent performance outside Cessnock subway station, we eventually managed to track down the group of avian musicians, who jokingly describe themselves as the "Banksy" of the music world because no-one knows where they'll pop-up next.
Nesting in dressing room four of the Southside venue are the now unmasked Janine Fearne, 31, Nadia Rossi, 29, sisters Greer and Ruby Pester, 25 and 27, and their conductor/leader Sarah Kenchington, 48.
Janine is relaxing with one large black webbed foot dangling in the air, while Nadia takes time to adjust her 'feathers' - layers of rubber surgical gloves packed with stuffing.
At the girls' feet rests the powerhouses of the whole operation - large black rubber rings full of air which is then pumped into the trumpets through a bellows system, like the Michelin tyre equivalent of a bagpipe.
"I came into this as an instrument maker," explains the system designer Sarah Kenchington.
"I've got a giant, pedal-powered instrument which I play on my own, but I also build instruments for other people to play. Last year I did a huge pipe organ for the Edinburgh Festival and then I was asked to do something for the Commonwealth Games which was a bit more portable."
As a Glasgow-based musician and composer, Sarah was drawn into the commonwealth fold from her history as an artist who builds her mechanical instruments from discarded materials.
From bicycle spokes to typewriters, she combines everything she can find to create unique musical machines that happily squeak, chirrup and chime their way into people's hearts.
"The Trumpet Swans started off just as trumpets with bellows as shoes," Sarah said.
"In a way the costume was an afterthought, but it all came together. Initially we were going to be trumpet playing Highland Cows, but I thought the swans would be a bit easier to manoeuvre."
"We've worked together before on performance projects with various crazy guises," Janine added.
"We've been giant salt and pepper sets, roast dinners, clams. We were headless chickens once too I think ... ."
Sarah's latest venture is a crossover between experimental music and people who dress as animals which the group of artists describe as a performance which has left adults baffled but children in awe.
"It's been a largely mixed reaction," Janine said.
"We've found our target audience, which is probably about three and below. They seem to appreciate it and go into a sort of jazz trance while we play our four hits.
Sarah said: "We had an enormous crowd at Glasgow Green while we were setting up."
"We started playing and everybody got up and walked away. We were just left with all the children sitting avidly thinking it was brilliant."
The women break into peels of laughter.
"We're calling it abstract avian jazz," said a chuckling Janine.
"I think adults find it surreal and aren't really sure what to make of it," agreed Sarah.
"I think you definitely have to think about what kind of sound a swan playing a trumpet would make when you listen to it, rather than see it as a brass band.
"I think people expect us to do some kind of Paul McCartney thing and that's just not going to happen," Sarah added laughing.
For now, the group of Trumpet Swans are set for Glasgow once again on August 17th at Queens Park for a performance from 7pm.
Before that though, they'll migrate eastward towards Edinburgh for the Fringe where they have an event on August 9 at Garage, an artist-run space that hosts exhibitions and mini-residencies out of - you guessed it - garages in Edinburgh.
"Who knows, maybe a Christmas special ... on ice," Sarah adds laughing.