Yes, just put a flat board like a 2x4 or a piece of old floor trim, ect and not too steep, so they can get out. They most likely fell into it. I had some old metal watering cans I decorated w a one day heard a noise in one, it was a lizard and some had already died in it.
I never thought about it, but they would get in it and it was too slick for them to get back up out of and they died in there. So I filled it up w rocks, and now they look great and the critters can escape and they do not hold water, (tiny holes in the bottom) so no skeeters either... It is not just window wells, even flower pots that you have a pot in a pot, they get between them and can't escape.