I put up a wood duck box about 4 weeks ago and I am still waiting for some to move in.I do have a pair of hooded mergansers that are hanging around.The articles that I read said that hooded mergansers will also use wood duck houses.
I added my boxes last year and notice a wood duck couple eyeing the box but did not take to it last year. This year I never saw them in or around the boxes and then here they are.
Tracy