After a few forgettable seasons, there are signs of life at NBC: Net’s not likely to escape fourth place this season, but it’s looking like it could challenge the leaders in some weeks this fall.

Of course, the net’s primetime Sunday NFL package is a seasonal anomaly that makes it especially competitive at this time of year, but it’s not just pigskin popping at the Peacock. One year after “Heroes” busted out at the top new show among young adults, NBC has another solid piece in “Bionic Woman.”

The new take on “Bionic” had the strongest bow of any new show this fall but slid about 30% in its second week, suggesting that some of the curious didn’t like what they saw. Still, if it stays at about this level, the Peacock will take it.

Add to this comedies “The Office” and “My Name Is Earl” and some decently performing new dramas like “Chuck” and “Journeyman,” and the net just may be starting to put the pieces of the puzzle together.

The nucleus of shows working at the Peacock these days are a reflection of its evolution from an older, more female-skewing net to one that, with football pointing the way, is now younger and more male.

NBC finished neck and neck with ABC for the lead among adults 18-49 during premiere week (with both nets claiming four of the top 10 shows) and narrowly topped the Alphabet among adults 18-34. Its median age of 45.2 was more than two years younger than last fall (47.6) and four years spryer than the fall of 2005 (49.6).

NBC also exhibited the best balance of any net, garnering a 3.9 rating in both men 18-49 and women 18-49 at the same time ABC’s aud was roughly two-thirds female.

The Peacock has gotten younger by jettisoning most of its crime skeins — “Law & Order” has been limited to one hour on the net’s sked for the first time in nine years — and sticking with some comedies that don’t do a whole lot of business among the 40-plus crowd. Also, newsmag “Dateline” has all but disappeared.

There are still some causes for concern — finding the show to replace “ER” on Thursday and a strategy to program Sundays after football chief among them — but there are no longer many timeslots where the net is not at least in the ratings hunt.

And becoming more competitive while getting younger is no easy feat.

Remote notes

Clearing out the notebook on some other early fall ratings observations:

  • Game over? They were good performers at the outset, but unscripted gamers and quizzers like NBC’s “Deal or No Deal” and “The Singing Bee” and Fox’s “Are You Smarter Than a 5th Grader” and “Don’t Forget the Lyrics” are having a tough time in the early going this season.

Of these, “Deal” is the oldest but it also seems to have the most left in its tank. Still, NBC is aware that it’s fading, already replacing one of the show’s two nights (Wednesday) in the November sweep with mentalist reality show “Phenomenon.”

  • Big Easier: New Orleans-set cop drama “K-Ville” hasn’t done much opposite brutal competish on Monday, but the net may be thinking of shifting it on Friday after skedding repeats on that night in place of the yanked reality show “Nashville.”

Its Monday average has declined steadily since its bow (3.3 to 2.3 to 2.0), but the net would like to give the well-intentioned show one more shot. At least on Friday it wouldn’t have to deal with the likes of “Heroes,” “Dancing With the Stars” and “Monday Night Football.”

  • Critical mass: It’s been a hit-and-miss start for the fall’s best-reviewed new shows.

While CW’s “Reaper” has done OK, the same net’s comedy “Aliens in America” opened meekly. Another well-reviewed skein, NBC’s “Chuck,” has looked solid but unspectacular in two airings.

But things looked better last week when ABC’s “Pushing Daisies” — which generated the best numbers of them all — opened to the best numbers for an 8 o’clock show in about year (12 share in adults 18-49 and about 13 million viewers overall).