Do cactus wrens eat popcorn?

I threw some leftover popped popcorn in the back yard to see if any birds would eat it, and there are over a dozen wrens (and two woodpeckers) out there now. The wrens pick up the kernels and fly under the shade of the orange tree with them and peck at them, but I can't tell if they're actually eating them. Are they? And is it good or bad for them? I've never seen so many wrens.