Ratings Chart Attack!

“American Idol” continues a slipping trend, putting up its lowest Wednesday night rating since April 2006 and its lowest season-to-date rating so far, excluding specials.

However, Fox’s “Idol” was still Wednesday’s highest-rated show in the 18-49 demographic, with a 9.6 rating/24 share, according to preliminary Nielsen numbers. “Idol’s” lead-in, “Moment of Truth” (4.1), was on pace with last week’s time-period premiere.

Fox placed first (6.8) for the night.

A special “Survivor” (3.6) helped CBS take second (2.6), but the Wednesday night airing drew the show’s second-lowest rating ever.

“Big Brother” (2.4) received a shot in the arm from the “Survivor” lead-in, pushing it to its highest Wednesday numbers this season.

Third-place ABC (2.1) aired new episodes of “Wife Swap” (2.1), “Supernanny” (2.6) and “Men in Trees” (1.6). “Trees” was essentially flat week-to-week, while “Swap” was down 13% and “Supernanny” was up 13%.

“Law & Order” episodes dominated the lineup for fourth-place NBC (2.0), with two episodes of “Law & Order: CI” (1.4, 1.7) followed by “Law & Order” (3.0), down 9% from its previous average.

The CW (1.3, 1.6 in the 18-34 demo) aired “America’s Next Top Model” (1.8), which was slightly down from last week, and a repeat of Monday’s “Pussycat Dolls Present: Girlicious” (0.8).

“Model” and “Girlicious” were just about on average within their key 18-34 demo.