When it gets hot, as it has been here lately, the bees hang out on the sides of the hive. They like the shadier places - under the tops, on the sides, in the handles, and at the edge of the bottoms. They hang in clusters that look like beards, which is why it's called 'bearding'.
They do this to free up space on the inside of the hive for more efficient cooling. Bees at both entrances fan air in or out and bees on the interior walls fan the air in one direction to circulate air efficiently. This is how they can control the inside temps so well so that the brood temps stay stable.
The number of bees on the outsides of the hives can give a clue to the strength of the hive. These are all first season colonies. You can see that the tallest hive has quite a few bees. It was started from a nuc. The long hive on the left has even more bees, but the design of the long hive gives a lot more interior space for them to be, so instead of bearding, they hang out in the far left end of the hive, where there is some extra space.
The beeyard smells like honey right now. The catalpas have been blooming and we have some just close enough that the bees are busy busy busy.