Singer Rokia Traore may have opened her show at the Birchmere on Monday night strumming an acoustic guitar and accompanied only by a backing vocalist, but she's no laid-back folkie: The barefoot, shaven-headed warbler put down the guitar for the more upbeat second song and was quickly joined by the rest of her band in a night that included more complex rhythmic sounds.

A Malian diplomat's daughter who has lived in the Middle East and elsewhere, Traore trills moral tales up and down the scales over both tradition-rooted strumming and -- as she proved in much of the set -- polyrhythmic dance music.

No matter the tempo, Traore's compositions followed a repeating modal style more than a poplike verse-chorus-verse format and featured a variety of instruments -- two ngonis (skin-covered lute), balafon (xylophone with slats on gourds), electric bass and others.

But Traore, who now lives in France, adds a contemporary tinge to that historically African method of songwriting. Although she lacks the lung power Malian star Oumou Sangare uses to keep such an approach ear-grabbing, Traore and her band had enough skillful tricks of their own to keep the small crowd enthused.

Emphasizing her latest CD, "Bowmboi," Traore loosened the arrangements, and her own limbs. "Kanou" became trancelike thanks to Traore's mystical harmonizing and slow-motion dance movements, as well as the band's Asian-feeling percussion. Mixing and matching several different Malian ethnic styles on "Sara" and the two funky encores, Traore sang sweetly and shimmied as the ngoni players frenetically plucked out high-toned notes and the percussionists happily banged, pinged and tapped away.

-- Steve Kiviat