Potentially, what is, or was in there, now that its cold or will be, (it don't take too long before they dwindle down) but get a nest at its peak, the link to the video shows it well.
They do leave a sentry out at all times, not sure about when it cools off in the fall, but when its warm, nest is full, peak etc., they are immediate if disturbed, yet if not, you can stand near their flight line not far from the nest and they just go around you if in the way. I encountered one in a bush I was mowing around, was that close, later on went for a look at this late summer full size nest, basketball size, was no bother to them at all, then tossed a stick on the nest from a safe distance, instant reaction, then calm and back to work, not long after you can stand near the nest again.
In this video, they mark the camera with pheromone and then assault it violently, they have a hard shell body, you can hear it. Apparently, thats what signals them, they go to it and attack, so if one gets you, its likely all the rest are too if you get that pheromone on you.
These things when disturbed, are by far the worst to deal with we have around here, always have to be on the look out when clearing brush. I stepped on a ground hornets nest not long ago, humbled by natures finest little yellow jackets, those white faced ones, given the same number of times I got nailed, that would have been some misery, these and those brown paper wasps pack a punch, I'd rather voluntarily stomp on a nest of those ground yellow jackets, then deal with either of the previous. Those maroon wasps down south, they do not look like much fun either, all best to avoid !!!
Hornets attack camera