Katie Couric’s (photo) successor as “CBS Evening News” anchor faces an extraordinarily difficult job in lifting the network out of the ratings cellar. Couric will leave her post after nearly five years, with her contract expiring on June 4, according to a network executive who spoke to The Associated Press on condition of anonymity because Couric has not officially announced her plans. The 54-year-old anchor is expected to launch a syndicated talk show in 2012. She took over a broadcast that had spent many years in third place behind NBC and ABC in the ratings, and leaves it in third place. New CBS News Chairman Jeff Fager will choose Couric’s successor, and will look both inside and outside the company. Many people at CBS News believe that Scott Pelley of “60 Minutes” is the lead contender. … The young women of country ruled the Academy of Country Music Awards on Sunday night with Taylor Swift winning the prestigious entertainer of the year award and the night’s top nominee, Miranda Lambert, taking home four trophies. Swift covered her mouth with her hands, did a little dance and hugged Brad Paisley and Lambert on the way to the stage after winning the fan-voted award, the only major ACM award determined by popular vote; peers and industry insiders determine the other awards. “This is the first time that I’ve ever won this, and I’m just losing my mind,” said the 21-year-old, whose album “Speak Now” sold 1 million copies in its first week when it was released last fall. Lambert, 27, was also up for entertainer of the year. While she lost that award, she was the night’s big winner. Lady Antebellum continued its scorching run behind its breakthrough album “Need You Now,” finishing the night with three trophies. The trio of Hillary Scott, Charles Kelley and Dave Haywood, who won five Grammys earlier this year, won album of the year as artist and producer, and also won top vocal group for the second straight year.