Social satirist Michael Moore’s anti-gun documentary Bowling for Columbine and David Hare’s dead-serious adaptation of the Pulitzer Prize-winning novel The Hours took top honours on Saturday at the Writers Guild of America Awards.Moore’s win for best original screenplay marked the first time a documentary feature has been so honoured by the Writers Guild, and Hare’s award for best adapted screenplay gives The Hours a major leg up on the competition for that prize in the Oscars this month.Many members of the Writers’ Guild Awards, which represents US film and television writers, also cast ballots for the best-screenplay Oscars as members of the writers’ branch of the Academy of Motion Picture Arts and Sciences.Last year, both of the WGA’s top winners, Julian Fellowes’ Gosford Park for original screenplay and A Beautiful Mind by Akiva Goldman for adapted screenplay, went on to win the Oscars in those categories.Bowling for Columbine, which also was the first documentary feature ever nominated by the Writers Guild, earned an Oscar nomination as best documentary.The Hours, which stars Australian star Nicole Kidman as British novelist Virginia Woolf in a story of three women’s lives intertwined around Woolf’s novel Mrs Dalloway, also is in the Oscar running for best picture. Kidman was nominated for lead performance and Julianne Moore picked up a nomination as best supporting actress.Moore’s film edged out My Big Fat Greek Wedding, Far From Heaven, Gangs of New York, and Antwone Fisher among other films.‘‘Our members’ appreciation of Michael Moore’s clever, humourous and personal storytelling is a tribute to his vision and the power of his subject matter,’’ Victoria Riskin, president of the Writers Guild of America, West said in a statement.‘‘In such an outstanding year for writing it was especially difficult for our members to choose just one,’’ said Herb Sargent, who is the president of the Writers Guild of America, East.