Later I went out to remove the food and water bowls from near the shed, and I looked in and saw no sign of the kittens. There are a couple of places in there they could have been hiding, but I didn't inspect too closely. Just in case they were still there, I didn't want to chance giving them yet another fright. But I'm pretty sure they're gone. Maybe now that the food and water have been removed the mom cat will bring them back, but probably not. This place probably doesn't feel safe to her anymore.
But the lawn has been mowed.
I don't like what I have to fix for dinner. I'd better get it over with.