BOSTON (AP) — Massachusetts' political center of gravity is shifting to South Boston in anticipation of the annual St. Patrick's Day Breakfast.

The Sunday gathering is traditionally an excuse for the state's top politicians to trade bad jokes and test their vocal skills with Irish songs.

This year one focus of the breakfast will no doubt be the state's special U.S. Senate election sparked by the resignation of former Sen. John Kerry to become secretary of state.

South Boston native Stephen Lynch and Edward Markey are vying for the Democratic nomination while Gabriel Gomez, Michael Sullivan and Daniel Winslow are competing on the Republican side.

Another big target of jokes will likely be Gov. Deval Patrick and his push for a hike in the state income tax to fund transportation and education improvements. Patrick will address the event by video.