Adding his trademark whimsical storytelling, instrumental virtuosity and ever-present sense of humor to Symphony Center’s America 250 tribute, Grammy Award-winning mandolinist Chris Thile returns for his second appearance of the season — this time with the Chicago Symphony Orchestra. A founding member of Nickel Creek and Punch Brothers, the singer and composer performs ATTENTION! A narrative song cycle for extroverted mandolinist and orchestra — alongside vivid works by Barber, Copland and Caroline Shaw.