I would love to see some pictures of the boxes and where you placed them. I have built a couple but I haven't put them out yet. Are they mounted on trees or poles?
I used some ideas from a PB article. I used 4 inch PVC instead of poles. They are in the water (put them in during low tide). Put them where they can't see both boxes. Otherwise you have egg dumping.
If you cut the holes the right size, you may also get black bellied whistling ducks. They are fantastic parents. They stay with the babes for four months! Also not very skittish.
