TV Ratings: 'American Idol' down but still on top, 'Bones' spin-off pilot makes solid debut

Fast National ratings for Thursday, April 21, 2011

A block of reruns on CBS helped FOX maintain dominance over  Thursday night in average viewers and adults 18-49 -- despite a slight audience drop for the "American Idol" results show.

Also worth noting: the special backdoor pilot episode of "Bones." The potential spin-off dipped slightly in its second half hour, but still managed to be the top performing scripted series of the night.

FOX averaged 15.4 million viewers and a 8.9 rating/15 share in households, with CBS in second (8.5 million viewers, 5.4/9). NBC (4.6 million, 2.8/5) topped ABC's evening of reruns (3.8 million, 2.4/4), with the networks placing in third and fourth, respectively. The CW was down a bit from the previous week, with 2.3 million people and a 1.5/2.

FOX also won the adults 18-49 demographic with a 4.4 rating, besting NBC (2.1), CBS (1.8), ABC 1.1) and the CW (0.9).

Thursday hour by hour:

8 p.m.

FOX: "American Idol" results (19.6 million viewers, 11.1/19 households)
CBS: "The Big Bang Theory" rerun (7.0 million, 4.5/8)/"Rules of Engagement" rerun (5.5 million, 3.6/6)
ABC: "Wipeout" rerun (4.7 million, 2.8/5)
NBC: "Community" (3.3 million, 2.2/4)/"The Paul Reiser Show" (2.5 million, 1.8/3)
The CW: "The Vampire Diaries" (2.65 million, 1.7/3)

18-49 leader: "American Idol" (5.6)

9 p.m.

FOX: "Bones" (11.1 million, 6.6/10)
CBS: "CSI" rerun (8.4 million, 5.3/9)
ABC: "Grey's Anatomy" rerun (3.9 million, 2.6/4)
NBC: "The Office" (6.8 million, 4.1/7)/"Parks and Recreation" (5.1 million, 3.0/5)
The CW: "Nikita" (1.9 million, 1.3/2)

18-49 leader: "Bones" (3.2)

10 p.m.

CBS: "The Mentalist" rerun (10.96 million, 6.8/11)
NBC: "30 Rock" (4.6 million, 2.8/5)
ABC: "Private Practice" rerun (2.7 million, 1.9/3)

18-49 leader: "30 Rock" (2.2)