Buzz, buzz, buzz.

That’s the sound that bees and movie fans make in the spring. And for the same reason – they’re both anticipating the summer.

Only you might have to listen extra hard this year.

The mainstream media, normally a bee-loud glade by March, have been unusually slow to promote the big summer blockbusters, observers say.

“I think they’ve been very low-key about the summer releases,” says Drew McWeeny, West Coast editor for Ain’t It Cool News, a 10-year-old Web site devoted to Hollywood buzz.

Quick, how many 2006 summer films can you name right now? “Over the Hedge” (May 19)? “Nacho Libre” (June 2)? “Cars” (June 9)? “Click” (June 23)? “Lady in the Water” (July 21)? “The Ant Bully” (Aug. 4)? “Apocalypto” (Aug. 4)?

Even the Super Bowl, normally ground zero for launching summer release campaigns (remember “Independence Day”? “The Matrix Reloaded”?), was surprisingly light on Hollywood hype this year, McWeeny says.

“Normally with the Super Bowl, you see this lineup of all the movie ads,” he says. “It’s always been a great place to jump-start the movie summer. Didn’t happen this year. The only one was ‘Mission: Impossible III’ (May 5). No ‘X-Men.’ No ‘Superman.’ Come on – it’s the Super Bowl and there’s no Superman spot? It seems so obvious.”

Jack Black plays Nacho, a benevolent wrestler, in Nacho

So far, there are only “teaser trailers” – those extra-short coming-attractions reels with brief glimpses of action – for two of the summer’s most anticipated films, “Superman Returns” (June 30) and “Miami Vice” (July 28).

Other sure-fire films, like “X Men: The Last Stand” (May 26) and “Pirates of the Caribbean: Dead Man’s Chest” (July 7), may be slower to get into the ad game for a practical reason: The F/X, such a big part of these movies, may not be finished yet.

“When you have so many summer films coming at once, the visual effects companies literally don’t have enough people delivering the work,” says Harry Knowles, founder of Ain’t It Cool News. “Work is being delivered very slowly, at the last minute.”

At a time when movie attendance is down (7 percent in 2005), along with general interest in Hollywood (Oscar ratings were 10 points lower this year), some people believe that nervous studios simply aren’t promoting like they used to.

Especially in the aftermath of a supposedly “disappointing” 2005 summer, when super hits (“Star Wars: Revenge of the Sith,” $380.3 million; “War of the Worlds,” $234.3 million) seemed to get less ink than duds like “Stealth” ($32.1 million) and “The Island” ($35.8 million).

“I think the pervasive attitude in Hollywood is very careful, very calculated, all about the money,” says Mark Ehrenkranz, producer of the New York Film Critics series.

Others, like Knowles, believe that the 2006 summer campaign is not so different from other years. It just intensifies several trends that have been apparent for a while.

For one thing, studios are putting their big promotional bucks into their next-in-line releases rather than advertising six months ahead of time. Which is why “Mission: Impossible III” (May 5), “Poseidon” (May 12) and “The Da Vinci Code” (May 19) – the first horses out of the gate – are getting all the exposure right now.

“The big, massive campaigns are going to be unloaded in the three weeks prior to release,” Knowles says.