sound:

One of the most puzzling things about Thea Musgrave's music is that we only tend to hear substantial examples of it when a special birthday comes along.

This year, the grand old lady, who is Scotland's only truly noted female composer of her generation, celebrated her 80th birthday, and lo and behold, her music has been featured in this year's BBC Proms, the BBC Scottish Symphony performs Aurora in Glasgow next week, and a brand new work is about to be premiered by the Scottish Flute Trio (SFT) at the north-east of Scotland's very own contemporary music festival, sound.

As if to press the point home, the other work of Musgrave's which the SFT is performing as part of sound – as an integral part of tonight's choreographic collaboration with the Curve Foundation Dance Company – is one the group previously commissioned from Musgrave in the run up to her 70th birthday, Voices from the Ancient World.

It would be all too convenient to suggest that the cause of such sporadic outbursts is the simple fact that Musgrave initially emerged as a composer in Scotland at a time when it was an unfashionable craft for a woman.

But that would be to ignore the considerable success she enjoyed earlier on in her career, especially in the 1970s, when she herself conducted performances of her opera Mary Queen of Scots with Scottish Opera, and, at the 1971 Musica Nova Festival, the premiere of her Horn Concerto, which revealed a composer unafraid to experiment with spatial orchestral effects.

It is more likely the fact that Musgrave followed these successes with a move to the United States, where she has lived and worked ever since, that has obscured her from our immediate awareness. Nonetheless, it is specifically because of her gender that her music finds a place among the more extended Scottish Women project that the Scottish Flute Trio is unveiling during its Sound appearances.

According to the group's principal flautist, Ruth Morley, Musgrave's 80th birthday was the key inspiration for a collective set of five works by female composers who either hail from, or work in, Scotland. The others are Sally Beamish, Pippa Murphy, Kirsty Blackwood and Audrey McPherson. experiment with spatial orchestral effects.

That's a fascinating spread of age and talent which promises a genuine representation of Scottish female talent. Musgrave's contribution – called Taking Turns – clearly positions her as the elder stateswoman. "It's a work that is typical of Thea," Morley explains. "It is not so programmatic as the previous piece she wrote for us, which was about Greek gods and goddesses, but it is very lyrical, very characterful."

At the other end of the age spectrum, Kirsty Blackwood has just graduated from the Royal Scottish Academy of Music and Drama, now a thriving generator of new compositional talent. Morley describes Blackwood's piece, Elastic Cast, as "more about rhythmic motor". Where its real interest lies is the way its "cast" can change slightly every time it is played, she explains, adding: "No two performances will be the same."

Even at this late stage, Morley and her colleagues have an incomplete picture of what all the Scottish Women commissions will ultimately sound like. "It's early days, and we're just getting the scores in," she says, pointing out that the works are all scored for an extended ensemble that adds percussionist Rhian Macleod and cellist Robert Irvine (Sally Beamish's husband) to the core line-up of three flutes. One of the works whose ink is barely dry is Changing Paths by the Edinburgh-based Pippa Murphy, although Morley has seen enough to describe it as "pastorale, taking a bit of influence from Thea's music".

For Beamish, the influence for Aquarium has been her daughter's fascination for tropical fish. "Sally's become obsessed by them," says Morley. "You can hear that clearly in the flashing movements of the music."

The one remaining piece in the set is Wanderlust by Audrey McPherson (wife of composer Gordon McPherson), who has recently turned her attention back to composition after a period spent in teaching. It's tempting to ponder whether there is anything intrinsic in these works that brands them as products of the female muse. If anyone could define such a trait it would be Morley or either of her colleagues in the SFT. During the ensemble's 14-year existence it has commissioned an astonishing 23 new pieces, a good number of them from female composers.

"I can't imagine that you can tell simply by listening [what the gender of the composer is], though we've never done an all-female composer programme before. Maybe we should do a survey on that question, though I'm more inclined to think that the difference between composers is more to do with individual character, not sex," she says.

And that's true of Thea Musgrave whose music is more important because it is interesting, intelligent and distinctive. Even at 80.