Conundrum

I can't seem to figure this out out: on the side of my house, in my rose bed, I've planted nasturtiums, and twice now someone/something has very carefully pulled up the seedlings -- roots, seed & all -- and laid them on the soil. Everything is intact, and no part of the very delicate seedling is damaged. It would seem to be the work of a creature with a sensitive pincer grip, so I doubt it's a squirrel/bunny/jay/robin. I can't imagine an adult doing this, and there seems to be little evidence of any children visible ever on the street. Ideas?