These critters look like bumblebees, but they’re squash bees, native to the Americas, working over a squash blossom just inside the garden gate. Much smaller than carpenter bees that drill holes in nearby garden posts, a bit smaller than bumblebees, and good to have around when you’re raising squash!
I noticed the third bee only after looking closely at the picture.
This is a handheld tight macro with the Canon SX230HS using the flash. Surprisingly, the autofocus target picked out the bees and tracked them quite well. A tripod would help, but not all that much.