We are the very lucky owners of a bumblebee nest. The bumblebees are in the lower portion of the planter, and are probably everyday white-tailed bumblebees. They are very active and you can see them flying in at all points of the day.
Please be careful when you are near this area, as although bees are not aggressive, if the nest is threatened they will protect it.
Please visit BumbleBee Class Page for a short video of them: