Northern Prairie Wildlife Research Center
Geese will use a variety of nest compartment sizes, but 26 to 32 inches wide structures are most manageable. Structures should be 8 to 12 inches deep so they retain the nest material. Because goslings and ducklings have difficulty getting over a 4-inch vertical rise, a slot or hole must be cut near the bottom of the structure, or a 6-inch wide hardware cloth (1/4 to 1/2 inch mesh) ladder must be installed so goslings can exit the structure. Without an exit, the structure is a death trap. Drainage holes must be drilled in the bottom of any solid structure so the nest material remains dry.
Steel pipe makes the best over-water mounting post because it is durable, easy to install, and difficult for predators to climb. A good choice is heavy-duty pipe with a 1 1/2 inch inside diameter. For soft pond bottoms or areas subject to ice movement, heavy duty pipe with a 2 to 3 inch inside diameter is better. Suitable pipe can often be obtained at salvage yards. To prevent bending from ice movement, the pipe can be filled with concrete to the normal water level. To prevent the pipe from being pushed over in a soft bottom, 1/8 to 1/4-inch thick steel triangular fins, at least 3 inches wide and 6 inches long, can be welded to the lower end (Figure 3). Treated or cedar wood posts can also be used to mount structures over water but should be protected with a predator guard mounted such that the top of the guard is 3 feet above the high water line (see Figure 13).
Over-water nest structures should be installed in 18 to 36 inches of water so the structure's bottom is 3 to 4 feet above the normal high water level. Where conditions permit, structures should be placed about 30 to 50 feet from shore, outside dense cattails, and 150 to 300 feet apart. Because shifting ice is the major cause of structure damage and loss, structures should be placed in sheltered locations whenever possible (see Figure 1). Placing structures close to potential loafing sites, such as logs, rocks, islands and points, will also increase their use by geese. More structures can be added and placed closer together as use increases.
When geese are consistently nesting in structures, it may be desirable to place the structures on shore to simplify annual maintenance. However, structures placed on shore should be mounted 6 feet above the ground or a predator guard attached to reduce chances of predation (Figure 3 & Figure 13).
Over-water structures are easily installed through the ice. A hole is augered in the ice and the pipe driven into the bottom with a post driver. Care should be taken not to damage the top of the pipe in a manner that would prevent mounting the structure.
Please read "Nest Materials and Maintenance" section.