The wrens have fledged for the second time, and I cleaned out the boxes. They must have left on Friday, Aug. 19th, when we were away for lunch. You would have laughed! The boxes sit on a bracket, you can see it in the screen images below. It was the only way I could think of mounting them.

Goodbye little wrens! Fly safely!
August 20th
I put the ladder up. Grabbing the cordless drill, I actually tested it. Dead battery. I switched them out and I climbed up. I couldn't get access to the screws underneath, as the top ladder wrung was blocking it. Back down the ladder, lower it one step, and back UP the ladder. I managed to remove two of the three screws, but the third was stubborn. Back down the ladder for a screwdriver. Back up the ladder and I removed the third screw, and climbed down with the drill, and nesting box in either hand.
It is impressive, isn't it? They are teeny birds, and really stuff it in order to prevent other birds from entering. The only way of cleaning the boxes is to remove the bottom.
It's rather cool that they butted the nest up against the back wall. It was so delightful to hear them chittering for food. If they heard me, they shut right up.
I washed the inside of the box, and left it to dry. I know I'd seen them taking sticks into the red and white box, so after the green box dried, and I rehung it, I worked on that one. Washed the box off, debris removed, back up the ladder with the box in one hand, the drill in my other. This time there was a ledge beside my ladder. Despite that, I dropped a screw. I set the nest box on the top rung of the ladder to better hold the drill, and it fell off hitting me in the face and collar bone. Just to add injury to insult!

Ta da! Ready for next year! That said, I'm still peeking out of the kitchen window looking for them.