Northern Prairie Wildlife Research Center
The homemade nest structures described in this circular generally meet these requirements.
The North Dakota nesting structure (Figure 1) is very sturdy and should last 15 or more years when properly installed. This structure requires little servicing except for annual visits to replace nesting material.
|Fig. 1. The smooth support pipe and fiberglass tub of the North Dakota nesting structures make it virtually inaccessible to mammalian predators. (G. Enyeart)|
The structure's smooth support pipe makes the nest inaccessible to raccoons and other mammalian predators. This structure is relatively easy to install if the support pipe is driven through the ice during the winter. When properly installed, moderate fluctuations in water level can be tolerated. Although the North Dakota structures are generally considered to be sturdy, they cannot withstand the type of ice action normally encountered on large, open bodies of water.
|Fiberglass Tub||One 32- to 36-inch diameter, with 8-inch side wall and 2-inch drop bottom from side wall with 8° sidewall for stacking purposes and 5 x 7-inch escape opening. In earth tone tint and made of 1/8-inch fiberglass laminated of 70% polyester resin with U.V. stabilizer and 30% glass content.|
|Steel disc||One 20- to 24-inch steel farm implement disc or suitable substitute|
|Wood||One 20- to 24-inch circle of 3/4-inch exterior grade plywood.|
|Pipe||One 1-foot length of 3 1/2-inch I.D. pipe (4-inch O.D.)|
|Pipe||One 9-foot length of 3-inch I.D. (3 1/2-inch O.D.) pipe|
|Bolts||One 4 1/2-inch or 5-inch long 3/16-inch bolt with nuts and flat washers and four 3/16-inch eyebolts of appropriate length with flat washers and nuts.|
|Bale||One-half bale of flax straw|
Structure support pipe can be purchased either new or used from local scrap dealers. Nesting tubs can be purchased from either Pleasure Products Manufacturing Co., 2461 16th Ave. South, Moorhead, MN 56560, Raven Industries, Inc. Plastics Division, Box 1107, Sioux Falls, SD 57101, or Hanson Manufacturing, Inc., Turtle Lake, ND 58575. Similar tubs may also be available from other manufacturers.
Four holes are burned through the steel disc with an acetylene torch and four matching holes are drilled through the bottom of the fiberglass tub and the plywood circle. The 1-foot length of 3 1/2-inch inside diameter pipe is welded to the disc. These components are then assembled and bolted together with four 3/16-inch eyebolts, using washers as necessary (Figure 2).
|Fig. 2. Construction of the North Dakota structure and pipe driver is relatively simple although welding equipment is required.|
Matching holes are drilled in the 1-foot length of pipe and at the top of the 9-foot support pipe. A 1/2-inch diameter drain hole must be burned in the support pipe. This hole should be about 18 inches down from the matching hole. This drain hole will prevent water from remaining in the support pipe over winter. Past experience has shown that water confined within undrained support pipes may expand enough, upon freezing, to break the weld between the disc and the 1-foot length of pipe.
The 9-foot length of 3-inch inside diameter support pipe is driven into the marsh bottom at a selected location. The tub assembly with nesting material installed can then be set in place on the support pipe. A 3/16-inch bolt is inserted in the previously drilled holes in the two pipes and the nut is tightened.