Folk, jazz etc: 'Birdie Song' Karen relishes her busy parliamentary schedule

Since her debut solo album, Faultlines, scooped the Best Album prize at the 2005 BBC Folk Awards, Polwart has consolidated her stature as a contemporary singer-songwriter and an interpreter of traditional material. She was asked to sing at the Parliament opening through her involvement in Burnsong, the national songwriting development organisation, and she'll be accompanied by two other singer-songwriters from the project, Kim Edgar and Kirsty Grace, who was a winner in this year's Burnsong open songwriting competition for under-25s.

The opening will also showcase young Scottish talent, ranging from emerging rock bands to youth choirs, orchestras and pipe bands.

Polwart describes herself "delighted and flattered" to have been asked, but the big question was what to sing. One Robert Burns song and one contemporary song were required, and the natural inclination to go for Burns's egalitarian anthem A Man's A Man was pre-empted by Sheena Wellington's performance at the first Parliament opening in 1999. "Because it was done by Sheena then and because she sang it so majestically, we started looking for another song," says Polwart.

In the event, it was agreed she would sing Burns's haunting Song Composed in Autumn - more popularly known as Now Westlin Winds, accompanied by Edgar on piano. "On its deepest level, in my opinion, it's a love song to place and environment and how people and creatures of every kind co-exist within it," she says. "But it's also a call to human responsibility, and stewardship, as I see it, in order to mitigate 'tyrannic man's dominion', as Burns puts it."

From Polwart's own compositions - some of which can be quite dark, Kirsty Grace will sing the more optimistic Follow the Heron Home, accompanied by Edgar and Polwart. Heron is probably Polwart's most widely sung number. "I'm amazed at some of the places it's cropped up," she says. On the day of our conversation, she'd been singing to a coach of American tourists in the Yarrow Valley, that serene home of sanguinary ballads (and, yes, she sang them The Dowie Dens o' Yarrow). "Some of them knew Heron from singing it in choirs or community groups. And I was up at the Fis in Ullapool last month and I found out it's sung so often up there it's referred to as 'The Birdie Song'," she laughs.

Polwart also recently found herself on BBC TV's Later … With Jools Holland as part of the Burns Unit, the eight-strong collective which emerged from the Burnsong project, which also includes Edgar and Polwart's Canadian husband, drummer Mattie Foulds.This led to a backstage discussion with former Led Zeppelin bassist John Paul Jones, who'd been playing with Seasick Steve on the show, and was intrigued by Polwart's shruti box - the Indian bellows-blown harmonium which she uses to provide a drone accompaniment.

Firmly back down to earth, as we spoke she was about to head off for Edinburgh's Broomhouse Primary School to sing Katy Perry's Firework to eight and nine year-olds as part of the BIG Sing-A-Long children's music project. Next morning, she was due into a studio to start filming her first DVD.

"Yet another morning to get up and do something entirely different from the morning before," she says, with something approaching indecent relish.

• For further information, see www.karinepolwart.com. The opening ceremony can be viewed live and subsequently on the Scottish Parliament website: www.scottish.parliament.uk