They're doing that because a queen is inside that equipment.
Definitely call a beekeeper, we need all the bees we can get.
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I've had that happen before and they just moved on. The queen is in there, so she could be just resting. How long have they been there? By the picture it seems they are just passing through. Doesn't look like a good place to nest. They were clung like that on my tiller but were gone by same time next day.
They're doing that because a queen is inside that equipment.
Definitely call a beekeeper, we need all the bees we can get.
.