From the Evening Standard in England:
Sly and Arnie ‘killing thousands of bats‘
24 Jan 2012
They say the bats may starve in their thousands because the lights and cameras disturbed their winter sleep, leaving them disorientated and confused.
Stallone, Schwarzenegger and their crew entered the Devetashka cave in Bulgaria to film The Expendables 2, due to be screened this summer.