Very nice pictures there FF, thanks for sharing.
From the little I know about honey bees, that's called bearding, and I only know a few basics because my wife is a bee keeper. I've seen it before on the outside of her hives, when they stack up like shown in the pictures.
One thing you need to know is if you're in the close proximity of a hive, make sure you're not wearing a black shirt. Bees mistake you for a bear, and will attack to save the hive. We have a mostly black cat, and a mostly black dog, that have been attacked when they get too close to the hives, plus early on I made the mistake of wearing a black shirt when mowing grass near the hives.
I'm learning here, and there, just from my exposure to them. My wife says raising bees is relaxing to her, so if it relaxes her, I'm supporting her in it.
One other thing I learned last fall, was that yellow jackets can desimate a hive of honey bees in a matter of hours. They kill off the bees, and steal the honey. She lost 2 very good hives in a couple of days to yellow jackets. She did manage to get some of the comb out, before the yellow jackets emptied the hive. A whole season of bees, and hive, and a lot of labor, gone.
Next year we make sure that we keep all yellow jackets, and their nests, away from her hives.