Teresa Burton, from the Horticulture department of the Minneapolis Park and Rec. Board, is in charge of the installation and monitoring of wood duck houses at Diamond Lake. Here are her comments about the status of the houses this year with a picture of the material taken from one of the nest boxes:
“We put up two pole mounted houses with predator guards in the vicinity of the church on the south side of Diamond Lake last fall to be used (hopefully) this spring. In the spring we fill the houses with fresh woodchips and then return in the fall to check on the status of the houses, record data, empty, and clean. We record a variety of different things on each house. The presence of down, shells, whole eggs, presence of squirrels, wasps, owls, etc. This year both houses had a number of whole eggs (19 and 11) and no down or shells present. It would lead us to believe that the boxes this year may have been dump nests. It is also possible that something happened to the hen but as no down was present the dump nest seems more likely. Sometimes dump nests happen when there are too few or too many nesting sites in the area. Conflicting? I know. Sometimes things are a mystery. There are many different theories on whether dump nests are good or not so good. We consider a house used is a house successful.”
The following link gives a more detailed description of Wood Duck activity: http://www.woodducksociety.com/qanda.htm#A_Wood_Duck_Hen_and_her_Eggs: