From a Google search for 'Swiss 1311' -
January 10, 2010 - Swiss A319 at St. Petersburg on Jan 10th 2010, bird strike - A Swiss Airlines Airbus A319-100, registration HB-IPT performing flight LX-1311 from St. Peterburg (Russia) to Zurich (Switzerland) with 123 passengers and 5 crew, was climbing out of Saint Peterburg's Pulkovo Airport, when the crew reported engine (CFM56) vibrations prompting them to return to Pulkovo Airport. The airplane landed safely 40 minutes after departure. Russia's Transport Prosecution Office reported, that maintenance found evidence of a bird strike in the engine.