Viewers of the CBS Evening News Tuesday night would not have learned that Katie Couric will be stepping down as anchor of the nightly newscast at the end of next month. They would have heard about it if they had watched the other two network newscasts. On his report on NBC Nightly News, Brian Williams referred to Couric as "our friend and NBC News alum," a reference to her longtime tenure as cohost of NBC's Today show. On ABC, which reportedly has offered Couric a daytime slot to host a talk show, Diane Sawyer called Couric her "colleague and friend." Couric did discuss her departure with PBS talk-show host Tavis Smiley in an interview set to air tonight. Seeming to apologize for sidestepping earlier questions about her future plans, Couric said that she didn't "mean to be coy. I just didn't want to jump the gun on any kind of announcement, and I wanted to be respectful of my successor at the Evening News. " She did not indicate who her successor will be, although numerous reports have mentioned 60 Minutes correspondent Scott Pelley. Couric made no mention of the low ratings of the CBS Evening News during her interview with Smiley, explaining that she was leaving so that she could do "something that's a little more in my wheelhouse. While it was such a privilege to sit in that chair that was once occupied by Walter Cronkite, you know it's a pretty confining venue, and I'm looking forward to doing what I think is what I do best, which is interacting with people, interviewing people, having sort of more extended conversations." She said that a daytime talk show "might be a really good venue for my particular skill set."