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Homemade Nest Boxes For Cavity-Nesting Ducks

Predator Guards

Nest boxes, especially those made of wood, whether on trees or on wood or metal support poles or over land or water, should always be protected from below by a metal shield to prevent raccoons, mink, squirrels and other animals from getting to the box. Raccoons are responsible for the destruction of many duck nests in both natural cavities and homemade nest boxes. Proper precautions must be taken to keep them away from the nest. Raccoons are found throughout North Dakota, so precautions must be taken to keep them away from nest boxes placed in any suitable habitat throughout the state.

Materials needed

Sheet metal: one 3-foot x 8-foot sheet of 26-gauge sheet metal (for three predator guards)
Wood mounting blocks: Three
Stove bolts or metal screws: Three
Nails: six (for nailing mounting blocks and predator guard in place)

Construction

The following plan (Figure 16) shows how to construct a cone-shaped, sheet-metal guard for protecting nest structures from predators. The diagram shows how to cut three predator guards from a 3-foot x 8-foot sheet of 26-gauge galvanized metal.

When installing the guard, overlap the cut edge to the dotted line. The sequence of numbers on the solid lines is provided to facilitate cutting. Make circular cuts in a counter clockwise direction. The initial cut on line A-B can be started by making a slot at A with a chisel. Then proceed with a tinsnips. Be sure to wear gloves.

These cone-shaped predator guards work best on trees or wooden poles with a trunk diameter of up to 6 inches. As is shown in the plan, the cone-shaped predator guard is secured to the pole or tree with wooden mounting blocks and galvanized nails. The lower edge of the cone should be at least 36 inches above the ground or water.

Trees with a diameter over 6 inches can be guarded with a 33-inch band of sheet metal about 3 feet high which completely encircles the trunk. This type of guard can be attached with a nail and flat washer at appropriate places on the overlap. The band should be loose enough to allow for growth of the tree. This "wrap-around" type of predator guard is an option that can be used on any size tree and wood or metal support poles (Figure 17).

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