This May, Orcas Choral Society sings Bach’s joyful Mass in F and Vivaldi’s beloved Gloria, with soloists and a full orchestra of island and Seattle talents, including soprano Sharon Abreu and the members of the Skyros Quartet. Johann Sebastian Bach’s Mass in F, BWV 233, is one of four short “Lutheran” masses the composer wrote in the 1730s while music director of St. Thomas Church in Leipzig in what is now Germany. The piece recalls themes from several earlier cantatas. It begins with a graceful, lyrical Kyrie and dances through a lively Gloria and spirited Cum Sancto Spiritum. New to Orcas audiences, it will be a rare treat. Venetian composer Antonio Vivaldi, the “Red Priest,” wrote his famous Gloria in 1715, while serving as music director of the Ospedale Della Pieta orphanage in His home city. Like Bach’s Mass in F, the work recalls themes from earlier compositions. It’s great fun to sing and to hear, and is well known and much loved on Orcas.