Update to this story.

Via CBS News:

Pres. Obama’s summer vacation on Martha’s Vineyard began in earnest Sunday as he hit the links for a round of golf – his 300th since taking office.

“He shoots in the mid-80s to low 90s,” says an occasional golf partner of Mr. Obama’s, speaking on condition of anonymity.

He further describes the president as a competitive player and a serious scorekeeper on the golf course.

“Every shot counts,” says the occasional partner, based on over 20 rounds played with Mr. Obama. “He keeps score 100 percent,” and doesn’t take mulligans – do-over shots for which President Bill Clinton had a well-earned reputation on when playing golf.

In an interview last week with the Golf Channel’s David Feherty, Mr. Obama said of his golf handicap, “I’m an honest 13.”

By my count, this is Mr. Obama’s 38th time playing golf on Martha’s Vineyard during his seven visits split between three courses: Farm Neck in Oak Bluffs, Vineyard in Edgartown and Mink Meadows in Vineyard Haven.