Tracy,
Soon after we built our 1 acre pond back in 2009, I noticed several wood ducks hanging around, so I built two boxes and put them out in early spring, 2010. I put them on 1 inch conduit in about two feet of water and added a predator guard made from galvanized stove pipe. Woodies have raised two or more batches in each box every year since then, and so far, video monitoring has not found any instances of predators getting into the boxes.
Unfortunately, in my experience, the female always takes her brood away from my pond immediately after they hatch. I have woods with many sweet gums, oaks, and other trees, and have planted button bush and other attractants, but nothing has worked to keep them around.
One disadvantage of placing the boxes in the water is the danger to the ducklings when they leave the box.
https://www.youtube.com/watch?v=LWFF0ijnWx0. I guess that's one of the trade-offs in deciding to have both bass and ducks. Maybe the bass are one reason they leave after hatching. One more thing: A predator guard is no guarantee of protection. I did experience a rat snake getting past a similar commercial predator guard on my purple martin pole and wiping out a whole family of martins.
