An industrious pair of Organ Pipe Mud Dauber Wasps assembled their nest last August:
Their offspring began emerging in early July, with our first picture on 3 July. I’ll leave the image file dates in place so you can reach your own conclusions:
We think a titmouse (a known predator) pecked some holes, including the upper hole on the middle tube, as they seemed to expose solid (and presumably inedible) chitin from the outside:
More holes appeared in a few days:
The irregular spacing along each tube suggests they don’t emerge in the reverse order of installation:
Three days later:
Two weeks after the first holes appeared:
No more holes have appeared since then, so it seems one young wasp emerges every few days.
This nest produced about a dozen wasps, with perhaps as many launch failures. We’ll (try to) remove it and examine the contents in a few months.
We expect they’ll start building nests all over the house in another month …
Update: Fortunately for us, no nests appeared before the first freeze, so the wasps are holed up elsewhere for the winter.
The Smell of Molten Projects in the Morning 
Mud daubers were always fascinating to me. Fortunately they are also the least likely of bees to sting as well. Red wasps on the other hand …