New Amsterdam Singers, Led by Clara Longstreth Clara Longstreth, the music director of the estimable New Amsterdam Singers, has a knack for putting together engaging programs with a thematic hook. But as she notes on the chorus's Web site, a "theme is only good if every piece is a winner, not included just because it serves a theme." Ms. Longstreth, who has been conducting the New Amsterdam Singers for 44 years, put this reasonable thinking to good practice on Thursday night, when she led her 60-plus-member chorus in its final concert of the season, "Songs of Birds and Angels," a varied and beautifully performed a cappella program, at St. Ignatius of Antioch Episcopal Church on the Upper West Side. The initial idea for the program was to focus on poetry about the lark. The evening began with Copland's 1938 choral work "Lark," a harmonically pungent and syncopated setting of an ecstatic if sentimental poem by Genevieve Taggard. It ended with the New York premiere of Steven Stucky's "Skylarks," written in 2001, his feisty settings of six varied poems, including a haiku, Emily Dickinson's elusive "Split the Lark" and some Edward Lear drivel. But in choosing a program, good music should trump clever concept. Rather than pushing the lark idea to the limit Ms. Longstreth included visits to the cuckoo, falcon, owl, bat and a generic bird. She even included a symbolic figure with wings, the angel. I suspect the main reason an angel made it into the program is that Ms. Longstreth thought her singers and the audience would enjoy the Finnish composer Einojuhani Rautavaara's 1993 "Erste Elegie" ("First Elegy"), a long, mystical, agitated setting of a dark, visionary Rilke poem about a wondrous and terrifying angel. Max Blum, the chorus's assistant conductor, led an urgent account of Kirke Mechem's restless, harmonically slinky "Caged Bird," in which the poet Paul Laurence Dunbar (a son of former slaves) identifies with the misery of a bird in captivity. The chamber chorus, a subgroup of 28 singers, sang the New York premiere of three lively, engaging and lighthearted "Shakespeare Songs" by the composer Matthew Harris. The words come from lyrics in the Shakespeare plays that would have been performed with tunes of the day. The chamber chorus also gave a lovely performance of three pieces from Brahms's "Lieder und Romanzen." It was especially touching to hear "Fahr wohl!" This wistfully joyful farewell to a little bird was performed at Brahms's funeral.