This plan modified from kestrel nest box plan featured in Woodworking for Wildlife: Homes for Birds and Mammals (Published by Minnesota DNR; Carrol Henderson, author)

Design

There is no standard design for a nest box.  Birds do not insist on their nest sites being mathematically precise.  What they do require is a nest box that is secure and weatherproof, as safe as possible from predators, and of satisfactory dimensions (box height, depth and floor, diameter of the entrance hole, and height of the hole above the box floor).

Although there are prescribed standards, different bird species favor different types and locations of nesting sites, so boxes must be constructed accordingly to meet these different needs. 

Kestrel nest boxes are easy to make or may be purchased at various home and garden centers and bird enthusiast stores.  While many different types of nest boxes have been tried, conservation groups in Iowa have had success with the kestrel nest box design provided on this Web site.  It also provides enough board above and below the box for wrapping the banding material to secure the box to the signpost.

   Painted pine             Natural wood                    

Materials

If you look through any book or catalog you’ll see bird houses of all sizes and shapes, made of materials you might not have thought of:  recycled paper, gourds, rubber, pottery, metal, and concrete.

Of all the available building materials, wood is the best material to use.  It’s durable, has good insulating qualities, and it breathes.  It makes no difference whether the wood is new or old, rough or planed, or softwood or hardwood. Manufactured board (plywood and chipboard) are not suitable for outdoor use.

The Iowa DOT suggests using strong, weatherproof and untreated materials, such as cedar, cypress or fir, to build your nest box.  After construction, apply a wood preservative (wood stain) to the outside of the box to increase its durability and help repel water.  Do not apply preservative to the entrance or inside of the box since the fumes from the chemicals could harm the birds. 

If you use white pine for box construction (as recommended in the plans), paint the box with water-based exterior latex paint to increase its useful life. Using earth-tone paint (avocado, tan, or gray) works best for the cavity nesting species.  The dull, light colors reflect the heat and are less conspicuous to predators, blending in with the environment.  Do not paint the entrance or inside of the box.

Regardless of which wood you select, gluing all the joints before you nail them will extend the life of your bird box.  Galvanized or brass shank nails, hinges, and screws resist rusting and hold boxes together more tightly as they age.

Resist the temptation to put a metal roof on your nest box.  Reflective metal is more likely to attract predators.

Kestrels do not carry in any nesting material, but rely on the natural materials commonly found in a tree cavity.  To simulate a natural cavity, place medium-sized wood shavings (not sawdust) in a layer about 2 inches thick in the bottom of the box.  The shavings will be used as bedding and by the female in forming a nest depression.

Place nest boxes so they face south or east for warmth, and away from the usual direction of wind and rain. 

Building procedures

Note:  While the dimensions shown are considered optimum, they can vary from 8 x 8 inches to 10 x 10 inches inside dimensions.  The hole can be from 9 to 12 inches above the floor.

Since these instructions involve the use of power tools, the DOT recommends parental/adult supervision of youth involved in box construction.

Step 1:      Cut the board into six pieces

·         One - 26” back piece

·         One  - 13” top piece

·         Two - 17” side pieces         

          (note special diagonal cut)

·         One - 7 ¾” floor piece

·         One - 15” front piece

Step 2:      Drill two ¼-inch holes near the top of each of the side piece for ventilation.  Without air vents, boxes can turn into bird ovens. 

Step 3:      Put a 3-inch entrance hole in the front piece about 3 inches from the top of the box.  A rough surface both inside and out makes it easier for the adults to get into the box and, when it’s time, for the nestlings to climb out.  If your box is made of finished wood, add a couple of grooves outside and inside below the hole.

Step 4:      Drill four ¼-inch holes into the floor for water drainage.  Water becomes a problem when it sits in the bottom of a nest box.  A roof with sufficient slope and overhang offers some protection.  Regardless of design, driving rain will get in through the entrance hole. 

Step 5:      Nail the sides to the back.

Step 6:      Nail the bottom to the back and sides.

Step 7:      Using the hinges, screw them onto the

                top and back.

Step 8:      Put wood chips or dried grass 

                clippings in the box for nesting.

Step 9:      If using pine, paint the box to prolong

                its useful life.  

Now that you've built your nest box, we're sure you're anxious to get in placed and mounted. Click on the "Place, protect and mount" button for information on the next step.