I see some suspicious teeth marks on one of those little pots. Looks familiar; sometimes I have wild nocturnal animals knock over my seedling pots, maybe because the soil smells of kitchen compost or something, but they seem to think the prize is at the bottom of the container. I guess I'll call it instinct, but it's also possible that the culprits are just being little assholes, as they've destroyed a lot of my work in the garden.