In a rare foray into staged opera, the Library of Congress gave the world premiere, on Friday and Saturday, of Libby Larsen's "Barnum's Bird (a Choral Opera)," an engaging piece centered on the P.T. Barnum-masterminded tour of the United States by Swedish soprano Jenny Lind in 1850.

Virgil Thomson's quirky, ensemble-narrated operas cast obvious shadows over "Barnum's Bird," but Larsen's melodic invention is more generous, her skipping polyrhythms less high-strung than Thomson's. Larsen dots her accessible score with references to American circus, barbershop and minstrel show traditions -- she even tosses Bellini's "Casta Diva" into the pot -- and her chamber orchestration erupts in all manner of wry commentary from siren whistles to birdcalls to kazoos.

Larsen's own libretto (written with Bridget Carpenter) is essentially a set of witty, dialectical vignettes, pitting art-for-art's-sake yearning against good old-fashioned hucksterism. Happily, she sets her words with a conversational deftness.

Tenor Gary Briggle's brightly sung, likably vulgar Barnum proved an apt counterpoint to Esther Heideman's wistful Jenny Lind, sung in a warm-centered, bell-like soprano. Mezzo Jill Ponasik was a puckish, adorable Tom Thumb. Baritone Bradley Greenwald phrased gracefully and showed amusing pique as Lind's smug singing partner, Giovanni Belletti.

Philip Brunelle (of Minnesota's co-commissioning Plymouth Music Series) conducted with obvious affection. Under Jon Cranney's spare, tongue-in-cheek stage direction, the cast acted with the breezy charm of musical-theater performers.

-- Joe Banno

Libby Larsen, composer of "Barnum's Bird (a Choral Opera)," which was given a loving premiere at the Library of Congress.