NBC is down also, and ABC only picked up some of those viewers, the rest have just quit watching.
Overall evening news viewership is down 1.9 million viewers, something like 8.3 percent.
Many people have become tired of the corporate media promoting stories beneficial to the corporations that own them, the corporations that provide their ad revenue, and politicians (on both sides of the aisle) that are owned by the corporations.
Citizens no longer have to passively receive "news" on their idiot boxes. They can now go online, they can follow stories they think are important from many sources, including international sources that may have a different perspective than the corporate trolls.
Those who like the corporate mush are still free to tune in, say "please, may I have some more?", and argue about who serves it up better.