You might go online and look for floating nests for geese and expand on these. Barrels, tires, wood hinged nesting boxes have been used. The problem is in the type of material that might best suit your environment.

We do not sell our plans, they are found in our book. However, the nesting platform that we use is only for shallow captive settings. This is why we would suggest that you look online for nesting platforms used by wildlife specialists. Bob Knox, Knox Swans and Dogs uses a hinged nesting box, again for a captive settings, but you might be able to modify for your needs. In the case of Bob and other swan breeders, they sell their products because they build, transport and set-up the nesting boxes for their clients. This process involves many miles and hours of labor which is why the cost. If you can use the idea and make it applicable in a wild setting, that would be outstanding. But, one of the problems we find in the captive as well as the wild setting is that some swans refuse to use a floating nesting box. Some swans prefer the natural reeds/grasses of the wetland/marsh areas and will only nest on nests that they build themselves. We hope this information is of benefit. The Regal Swan