Northern Prairie Wildlife Research Center
Providing nesting areas for wildlife is a popular and growing hobby for many North Dakotans. Building houses according to the proper specifications, placing them in the right habitat, and maintaining them can benefit both bird and mammal populations. If they are not monitored for detrimental species such as the house sparrow, they may actually do more harm than good.
It is important to realize that not all birds and mammals nest in cavities. Many birds, like the American robin or meadowlark, either build cupshaped nests in trees or nest on the ground. The nest box plans that are found in this publication are specific to wildlife that utilize a cavity, either within a dead or dying tree or a man-made structure such as a nest box.
Cavity nesting birds will accept any kind of nest box that they can enter. Before deciding on what kind of nest box to build, there are considerations which should be taken--the size of the entrance hole, interior dimensions, proper ventilation, and the capability to open the nest box for monitoring and cleaning. Do not construct a box for "birds" in general as most species require different sized houses and entrance holes. The following guidance and construction plans will provide specific plans for most North Dakota species.
For all practical purposes, wood is the only appropriate building material to use. Wood is a natural material with good insulating properties. Plastic and metal often overheat. Green "pressure-treated" lumber is impregnated with copper arsenate as a preservative. If the chemical is not applied perfectly, the wood is toxic to birds and humans. Exterior grade plywood contains dangerously high levels of formaldehyde and therefore is also not the best choice. The best woods to use are rough cut cedar or redwood. They naturally resist deterioration when exposed to sun and rain and the weathered look is inconspicuous and attractive.
Never paint or stain the inside of a nest box. If you want to paint the exterior, close up the box and paint only what you can see. Use an exterior grade latex paint and give the top a second coat. Choose a light shade which reflects most heat or a natural color such as green, tan, or gray. A heavy grade of linseed oil stain works well also. Houses that blend in with their surroundings are more appealing than brightly painted boxes and less likely to draw the attention of human vandals.
Nest boxes can be mounted in several ways. They may be attached to existing wood or metal fence posts, power or telephone poles, existing trees, or on wood or metal posts or pieces of pipe used specifically for this purpose. Utility poles are often suitable for mounting nest boxes; however, permission should be obtained from the utility companies before this is done. Discretion should also be used before mounting to trees. Do not place bird boxes designed for bluebirds on trees because this invites competition from too many other species.
Predator-proofing should, be considered for all bird nest boxes that are not mounted on steel fence posts or pipe. A piece of sheet metal, tin, or used aluminum plates from newspaper offices serve well to prevent predators from climbing wooden posts. Sheets should be stapled or screwed on around the outside of the wood post be at least 12 inches high. The bottom of the guard should be at least two feet above ground level.
Do not put perches on any bird houses. Only the unwanted house sparrows and starlings prefer perches. If house sparrows or starlings begin nesting in a bird house tear out the nest material as these species are not protected by state or federal law. Nests may need to be removed numerous times before these birds abandon their efforts.