“Never before have we counted less than 10,000 bats in wintertime,” Mr. Petrov said, adding that he hoped the rest had just been chased away to adjacent caves.
The environment ministry, which authorized the movie shoot, said last week in a statement that it had found no problem with the bat colonies.
But the experts insisted filming inside the cave never should have been allowed.
“It is home to 15 protected species of bats, or half of all bats found in Bulgaria,” Mr. Petrov said.
Researchers will perform a new count of the colonies next spring to assess the damage.
Filming in Bulgaria for “The Expendables 2,” starring Mr. Stallone, Arnold Schwarzenegger, Bruce Willis and Jean-Claude Van Damme, already was marred by an accident in which one stuntman died and another was injured during a lake scene involving an explosion.
The movie is due for release in August.
Christina Ricci’s stage debut last year apparently didn’t scare her off — she’s going back.
Producers said last week that the “Pan Am” star will join two-time Tony Award-winner Bebe Neuwirth in a Classic Stage Company production of William Shakespeare’s “A Midsummer Night’s Dream.”
Ms. Ricci made her Broadway debut last season in Donald Margulies’ “Time Stands Still,” replacing Alicia Silverstone and starring opposite Laura Linney, Brian d’Arcy James and Eric Bogosian.
LaBelle among performers slated for Super Bowl shows
Patti LaBelle, Bret Michaels and En Vogue are among the artists who will perform in free concerts during the week leading up to the Super Bowl in Indianapolis.
The Super Bowl Host Committee made the announcement Wednesday at a news conference at Lucas Oil Stadium, site of the Feb. 5 game, the Associated Press reports.