I put out one of those ant baits, that they take back and poison the colony. It seemed to be working, in that the ants marched out. I decided I didn't really want a dead colony of ants in the camera though so killed them as they emerged, so they never carried the poison back. What intrigues me is why they would want to be in there in the first place. I can;t believe that there are no better places to nest.