Installed two wood duck homes near the inlet area of my pond which is submerged natural forest. Used 10 foot of 4" pvc pipe for the poles. I intend to camo paint these, then coat with Tanglefoot. Although the posts are currently on shore, the water should be about 4 foot deep at full pool.
These precautions protect the nest from predators. The main are coons and chicken snakes, with snakes being the biggy.
I can see both boxes from my future home site, but they are not within line-of-sight of each other. It'll be a few months before the ducks hit the local real estate market, so we'll have to wait to see if I have marketed these condos correctly.