February ended with double milestones in television: the first-ever sweeps month victory among all viewers for FOX (search), and the first-ever fourth-place finish for once-mighty NBC.

Sweeps are held four months a year, when Nielsen Media Research (search) ratings are closely watched to set local advertising rates.

The rankings are set even though the current sweeps period runs through Wednesday. FOX will also win among the 18-to-49-year-old age demographic that advertisers pay a premium to reach.

FOX's first sweeps month win since the network began prime-time broadcasting in 1987 is slightly deceptive. Take the Super Bowl (search) out of the equation, and FOX would finish third behind CBS and ABC, Nielsen said.

Still, it shows the continued strength of "American Idol" and the development of a promising drama in "House."

It's a more alarming outcome for NBC, which has particularly struggled on Thursdays, a night it once dominated. NBC's viewership in February was down 15 percent compared to February 2004, Nielsen said.

Last week's ratings illustrated NBC's problems. It had only two programs ranked among Nielsen's top 15 most popular shows of the week — "ER" and "Law & Order" — and both of those dramas are more than a decade old.

NBC said the competition is closer than this month's ratings make it appear. Take away events like the Super Bowl, Grammys and Academy Awards from its competitors, and NBC would finish second among total viewers, the network said.

Fueled by the Oscars, ABC was a clear winner last week with an average of 14 million viewers (8.9 rating, 14 share). FOX was second with 12.1 million viewers (7.3, 11), followed by CBS at 11.8 million (7.6, 12), NBC at 10.1 million (6.7, 11), the WB at 3.5 million (2.4, 4), UPN at 3.3 million (2.1, 3) and Pax TV at 550,000 (0.4, 1).

ABC's Peter Jennings took some ribbing for his news special on UFOs — one newspaper ran a "picture" of Jennings with a space alien — but its strong showing of 11.6 million viewers eclipsed NBC's Thursday night comedies.

NBC's "Nightly News" won the evening news ratings race, averaging 10.6 million viewers (7.4 rating, 14 share). ABC's "World News Tonight" had 10.2 million viewers (7.1, 13) and the "CBS Evening News" 7.8 million (5.4, 10).

A ratings point represents 1,096,000 households, or 1 percent of the nation's estimated 109.6 million TV homes. The share is the percentage of in-use televisions tuned to a given show.

For the week of Feb. 21-27, the top 10 shows, their networks and viewerships: "Academy Awards," ABC, 42.1 million; "American Idol" (Tuesday), FOX, 28.3 million; "CSI: Crime Scene Investigation," CBS, 28.1 million; "Oscar Countdown," ABC, 27.7 million; "American Idol" (Wednesday), FOX, 26.7 million; "American Idol" special (Monday), FOX, 23.5 million; "Survivor: Palau," CBS, 21.6 million; "Without a Trace," CBS, 21.4 million; "Lost," ABC, 19.5 million; "CSI: Miami," CBS, 19.5 million.