Fox made it three for three in Thursday demo victories for the May sweep, as ”American Idol” once again dominated its slot and ”Bones” edged ahead of ABC’s ”Grey’s Anatomy” for the first time.

Thanks to the move of ”Idol” to the night in January, Fox has now won 17 consecutive Thursdays in adults 18-49, tying the record set by NBC at the start of the 1999-2000 season.

According to preliminary nationals from Nielsen, ”American Idol” averaged a 6.2 rating/19 share in adults 18-49 and 21.6 million viewers overall in the 8 o’clock hour , on par with last week and again beating the combined demo delivery in the timeslot of ABC, CBS and NBC. It was followed by ”Bones” (3.3/9 in 18-49, 11.0 million viewers overall), which was up a tick week to week and won its hour in 18-49.

CBS, second to Fox on the night, opened well as usual with ”The Big Bang Theory” (3.2/11 in 18-49, 10.5 million viewers overall) before losing 4 share points at 8:30 p.m. with ”Rules of Engagement” (2.3/7 in 18-49, 8.0 million viewers overall); look for CBS to try to improve the timeslot with a new comedy in the fall. The laffers were followed by the season finale of ”CSI” (2.6/7 in 18-49, 11.5 million viewers overall), which was up week to week and won in total viewers but still placed fourth in 18-49. And at 10, ”The Mentalist” led the broadcast pack in most key categories with a 2.6/7 in 18-49 and 13.8 million viewers overall , standing as the evening’s most-watched scripted program.

ABC started modestly with ”Wipeout” (1.7/5 in 18-49, 5.5 million viewers overall) but then jumped at 9 p.m. with ”Grey’s Anatomy” (3.1/8 in 18-49, 9.4 million viewers overall), which was down week to week, appeared to hit a firstrun series low, and slipped behind Fox’s ”Bones” for the hour’s 18-49 lead; finding a compatible, scripted lead-in for ”Grey’s Anatomy” figures to be a priority for ABC as it preps its fall sked. Closing out the night was ”Private Practice” (2.3/6 in 18-49, 7.2 million viewers overall), which was flat week to week and ran second among the broadcasters in most categories.

NBC started sluggishly with the season finale of ”Community” (1.4/5 in 18-49, 3.2 million viewers overall), which will be back next season but isn’t expected to continue anchoring the night. Following a repeat of ”The Office” at 8:30 p.m. (1.2/4 in 18-49, 2.6 million viewers overall), an original episode averaged a 3.2/9 in 18-49 and 6.2 million viewers overall, down a bit week to week. It was followed by original episodes of ”Parks and Recreation” at 9:30 (2.4/6 in 18-49, 4.5 million viewers overall) and 10 p.m. (2.0/5 in 18-49, 3.6 million viewers overall) and the season finale of ”Outsourced” at 10:30 p.m. (1.5/4 in 18-49, 3.0 million viewers overall).

At CW, ”The Vampire Diaries” (1.3/4 in 18-49, 2.8 million viewers overall) remained solid but saw no gain for its season finale. And rookie ”Nikita” (0.7/2 in 18-49, 1.9 million viewers overall) was off a tick week to week with its final episode of the season.

Preliminary 18-49 averages for the night: Fox, 4.8/14; CBS, 2.7/7; ABC, 2.4/7; NBC, 1.9/5; Univision, 1.5/4; CW, 1.0/3.

In total viewers: Fox, 16.3 million; CBS, 11.5 million; ABC, 7.4 million; NBC, 3.9 million; Univision, 3.7 million; CW, 2.4 million.