For the Birds: Basics of Building a Nestbox

For the Birds: Basics of Building a Nestbox

Birdwatching has become a popular pastime and with good reason. Birds are not demanding and don't expect anything in return for letting you observe them. Birds are fascinating to observe and can also be very entertaining. Wild birds are not boring and come in a variety of species, all with differing characteristics. Best of all, they can be found almost anywhere you happen to live -- in a plush condo in the city, in a log cabin down a dusty country lane, or right in the middle of suburbia!

To enhance your birdwatching pleasure, why not build one or two suitable nestboxes for birds that frequent your backyard?

Some Birds That Will Use Nestboxes

Research shows there are more than two dozen species of North American birds that use nestboxes (or birdhouses). Some of those species include bluebirds, robins, titmice, chickadees, nuthatches, wrens, tree and barn swallows, purple martins, owls, flycatchers, and woodpeckers.

Some Birds That Don't Use Nestboxes

There are many wild birds that don't use nestboxes, such as doves, cardinals, orioles, hummingbirds, just to name a few. However, this doesn't mean those birds won't nest in either trees or shrubs they might find in your backyard. It can be great fun to watch them build their nests using twigs, feathers, dried grasses and weeds, string or yarn, and various other bits and pieces of fiber.

Important Basics of Building Nestboxes

Before you decide to build a nestbox, first do a bit of homework about the birds you want to attract. Otherwise, you may find yourself with an impractical nestbox no bird will ever enter.

Wild birds are quite persnickety about manmade nestboxes, and will usually only nest in those they feel are suitable for them and their nestlings. They aren't apt to settle for a one-size-fits-all style. Amazingly, their God-given instincts tell them which sizes are right or wrong for them and their little families.

After you have defined the birds in your area and their nesting needs, you're ready to assemble your materials, select the proper design, and begin your nestbox building project.

A Word About Choosing Building Materials

Attracting Birds, Butterflies and Other Backyard Wildlife

This National Wildlife Federation book provides over a dozen step-by-step projects for families to do together, making getting back to nature easy, educational, and fun.



Nestboxes can be made from many kinds of material including plastic, pottery, metal, concrete, and gourds. However, nothing is quite as appealing to birds as those made from wood. Wood is an excellent choice of material as it breathes, provides good insulation, and is very durable. Some good woods to use for making nestboxes include fir, cypress, white pine, cedar, exterior grade plywood, and marine plywood. AVOID using pressure treated plywood, as it is usually treated with chromated copper arsenate. If birds should happen to peck on this type of treated wood, it can prove very harmful to them. Great rustic style nestboxes can also be made from natural logs.

When using wood, it can be treated with a nontoxic wood preservative to prevent the wood from rotting. Never treat the insides of nestboxes with stains or preservatives, as these substances contain toxic chemicals that can adversely affect birds. Birds are not fussy about the exterior color of their nestboxes. However, if you do decide to paint your nestboxes, use colors such as gray, beige, or green to help defray predators. DON'T PAINT the insides of nestboxes or their entrance holes.

When constructing nestboxes, use weather resistant glue on all joints before nailing them. To avoid rust use galvanized or brass shank nails, and either brass or coated screws and hinges. Avoid using metal roofs as they may attract predators.

Nestbox Designs and Dimensions

No matter how plain or fancy you want make your nestbox, it MUST meet the two critical needs of nesting birds: (1) their safety and, (2) appropriate dimensions.

Different wild birds insist on different nestbox dimensions. These include the nestbox height, size of the floor, diameter of the entrance hole, and height of the entrance above the floor. Wild birds are also particular about the placement height of their nestboxes.

There are almost as many specifications to follow when building appropriate nestboxes as there are species of birds that will use them. It isn't practical to list all of those specifications here; however, specifications for a few popular nesting birds are outlined below.

Species Floor of Box Depth of Box Hole Size Hole Above Floor
Chickadee 4" x 4" 9" 1 1/8" 7"
Bluebird 4" x 4" 8-12" 1 1/2" 6-10"
Titmouse 4" x 4" 9" 1 1/4" 7"
Nuthatch 4" x 4" 9" 1 3/8" 7"
Flickers 7" x 7" 15-16" 2 1/2" 14-16"
House Wren 4" x 4" 6-8" 1 to 1 1/4" 4-6"
Carolina Wren 4" x 4" 6-8" 1 1/2" 4-6"

For additional information, you may want to contact your local Wildlife Service or the National Audubon Society. They will be happy to provide this information for you.

Ventilation, Drainage, and Clean-Out

Every nestbox needs proper ventilation. Vents can be made under the roof's eaves by drilling a series of 1/4" to 1/2" holes under the eaves on each side. OR, if the side pieces don't quite meet the roof, drilling vent holes won't be necessary. For proper drainage, just drill a 1/8" hole near each corner on the floor of the nestbox.

All nestboxes also need an easy way to be cleaned and sanitized after each feathered family has taken flight, most especially before another family takes up residency. Nestboxes can get quite messy before those little nestlings get mature enough to take flight! Nestboxes having removable floors, sides, or roofs can be easily cleaned. Keeping your nestbox design simple and functional will make it easier for you to decide which clean- out approach you want to use. Just make sure you decide this before you begin construction.

Wood Needed for Making One "House Wren" Nestbox

  • One piece of 4-foot x 6-inch x 3/4" tight-knot cedar wood

Tools and Accessories

  • Fasteners, latches, hinges (as needed or desired)
  • Use only galvanized steel, brass, or stainless steel nails
  • Brass flathead screws are superb
  • Exposed latches or hinges should be either stainless or brass
  • Galvanized brads are great if using an air or electric hammer

Adhesives

  • Hot-melt glue gun
  • High quality weatherproof glue

The best method for gluing joints is to use a hot-melt glue gun with white (not amber) glue cartridges. This type of glue is waterproof, does a great job of filling joints, and sets up in 20-30 seconds.

If you don't have a glue gun, purchase premium weatherproof glue such as Titebond II. There are a variety of other good brands of weatherproof glue on the market.

Exterior Finishes (Use only if desired)

  • Lead-free exterior flat paint
  • Lead-free water-based or oil-based stain
  • Water-based or mineral-based preservatives (Use with caution!)
  • Acrylic paint (lead-free)

Tools

  • Hammer
  • Hand saw or table saw
  • Screwdriver
  • Drill with appropriate bit sizes

Instructions for Building a "House Wren" Nestbox

Dimensions for cutting roof, side, front, back, and bottom pieced, following the specifications for house wrens.

Floor of Box Depth of Box Hole Size Hole Above Floor
4" x 4" 8" 1 1/4" 4-6"

Cut One (1) Roof Piece 5-1/2 inches X 7 inches
Cut One (1) Roof Piece 4-1/2 inches X 7 inches
Cut Two (2) Side Pieces 4 inches X 5 inches
Cut One (1) Front Piece 8 inches X 5-1/2 inches
Cut One (1) Back Piece 8 inches X 5-1/2 inches

Note: Cut tops of back and front pieces at 45 degree angles for roof pitch.

Cut One (1) Bottom Piece 5-1/2 inches X 5-1/2 inches

Drill a 1-1/4" entrance hole in center of front piece about 5" from bottom.

Note: It is not necessary to place perches on nestboxes. If you do want a perch on your nestbox, use a piece of doweling 3/8" x 1-3/4" and drill a 3/8" hole about 1/4" deep under entrance hole, then glue doweling into hole.

Putting it Together!

Now comes the fun part -- putting together your "House Wren" nestbox!

(1) Attach front and back pieces to the two side pieces with both glue and nails, making sure all joints are smooth and even.

(2) Nail and glue the two roof pieces together as shown in photo. Next, center the pitched roof on the two end sections. After roof is properly centered, nail and glue roof to back and front pieces.

(3) Attach the bottom piece to the nestbox. Using four (4) 1-1/2" brass flathead screws, place one screw in each corner of bottom piece. It's helpful to first pre-drill a small hole in the wood where you want to countersink the brass screws.

When completed, you can decide whether or not you want to leave the exterior of the wood unfinished, or use one of the suggested finishes mentioned above. After all, your birdhouse should please YOU as well as your fine feathered friends! Remember -- NEVER paint or finish the interior or entrance hole of the nestbox.

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