When I was a kid, we called the wasps that make these nests Dirt Daubers. Or rather, Dirt Dobbers. Outside the south they are apparently known as Mud Daubers. (1, 2)
It took me a minute to realize what seemed so strange about finding one of their nests in the woods. I think it's the first time I'd ever seen one that was not attached to something manmade. We normally see them on buildings, under eaves or elsewhere out of reach of the rain.
Apparently, the Daubers aren't aggressive and don't sting often. Plus, they lay eggs on Black Widow spiders that they stuff into those pipes as food for their offspring. So, Daubers = on my good side.
Paper Wasps = on my bad side. The previous "just shoo them out the door" policy is history. The last one that got that treatment repaid me with a sting on the proximal interphalangeal joint of my index finger.
I looked up the medical name so that I could be specific about how painful it was.
According to Dr. Justin O. Schmidt and his insect Pain Index, the sensation is rated at
3.0: Caustic & burning. Like spilling a beaker of Hydrochloric acid on a paper cut.Schmidt is an stinging-insect expert -- if you run across an article on African giant stink ants, it's likely to have his name on it somewhere.
But his index is limited to bites and stings from insects. Nobody has done the important cross-indexing with spiders, snakes, platypus, jellyfish, and so on. Because you might just think pepsis wasps or bullet ants were bad, until you came across the Australian jellyfish that can cause Irukandji syndrome.