Most cavity-nesting birds eat the insects and other critters that wreak havoc in our gardens. We love it when we see a house wren with a wriggling cabbage looper in its beak: lunch for its babies and no more holes in our cabbage! These pest-eating birds, such as swallows, wrens, chickadees, titmice, and bluebirds, should be a welcome addition to your garden. And, since cavity-nesting birds like to nest in the holes of trees and other natural cavities, a nest box that mimics the type of cavity they prefer will probably attract them. Hang a few houses close to/inside your garden and soon you’ll have lots of natural pest control.
Step 1: Overview
We’ve built and installed a lot of nest boxes over the years. We followed one basic design, used cedar when we had it and only varied the design/size a bit. The box is easy to construct and installs with a screw on the inside back and one into the bottom of the back. We latch the front with a bent nail or other metal device so we can clean out the box in winter.
We have these boxes all around the garden and on posts throughout the pasture in western Oregon. We even have a line of barbed wire strung between two poles with boxes hanging from the wire. All of our 40+ nest boxes have been occupied at one time or another, by tree swallows, violet-green swallows, chickadees, house wrens, and bluebirds.
Step 2: Best Wood for the Job
Rough-sawn cedar or redwood is recommended for a nesting box because it will last a long time. If not available, use another type of untreated wood (preferably not plywood) that is 3/4" thick. Paint, wood preservatives and stains can harm wildlife so it is best not to use these products. While the house may not last forever, it is easily replaced using this simple design.
Step 3: Cut List
Use these dimensions or something close for bluebirds, swallows, chickadees, wrens, small woodpeckers and other cavity-dwelling birds of a similar size.
You need a total of about 6 linear feet (1.8 meters) of wood
One piece of 1 X 8” (2.5 X 21cm) cedar, 14" long (36cm) for the back, width unchanged (you can slant cut the top if you like, to match the angle of the walls)
One piece of 1 X 8” (2.5 X 21cm) cedar, 9" long (23cm) for the front, cut to 6" width
One piece of 1 X 8” (2.5 X 21cm) cedar cut to 6" (15cm) width, 6-1/2" (16.5cm) for the bottom (cut last for correct fit)
Two pieces of slant-cut 1 X 8" (2.5 X 25cm) cedar, 11-1/2" (29cm) at the longest and 9-1/2" (24cm) at the shortest. Cut two slots side by side at the top of each side, about 3/16" (2 cuts) wide and about 1/2" deep
One piece of 1 X 10” (2.5 X 21cm) cedar, 9-1/2" (24cm) for the roof (you can use 1x8 if you don’t care about overhanging the sides. It really won’t matter as long as the roof is flush to the sides - we've built them both ways)
2" (5cm) wood screws and nails if you're using them (we've also used staples)
One small 2" (5cm) nail (or copper wire, which will last longer) for a latch
Saw, screwdriver, drill, pliers, hammer
Step 4: Drill and Assemble the Box: Sides, Back, Front
1. Drill or cut a 1-1/2" (4cm) hole about 2-1/2" (6cm) from the top of the front for an entry hole.
2. Pre-drill a small hole in the center line about 2/3 height up the back.
3. Screw/nail the sides to the back, using three to four fasteners for each side. Pre-drill if necessary.
4. Line up the front so that it is even with the bottoms of the side pieces. This leaves 1/2" at the top of the front for ventilation.
5. Screw the front to the sides, one screw on each side, exactly 2" (5cm) from the top. These screws will act as hinges for opening the box so they need to be aligned across from each other and not super-tight.
Step 5: Roof and Bottom
6. Screw/nail the roof to the sides, front, and back, allowing a 1/2" (1.5cm) overhang on the back (if you used 1x10) with the rest hanging over the front.
7. Stuff the floor piece in about 1/4" (.63cm) from the bottom edges of the back, front, and sides, then fasten it into place from the sides.
Step 6: Latch It
8. Bend the nail or copper wire into an L shape with the pliers.
9. Drill a hole through one side, and into the front, then insert the latch.
Step 7: Ventilation Yes, Peg No.
This design has good ventilation, which is very important (and we've noticed a lot of designs don’t include it). A non-ventilated house on a hot day can potentially result in baby bird mortality.
The design also does not have a peg beneath the entry hole. This is not necessary for cavity-dwelling birds - they use their claws to cling to the outside of the hole when necessary. A peg only allows predators such as crows to reach inside the box.
As for which direction to face your nest box, generally southeast is recommended where we are, though I've read people find due east to be best, with north, south and west in order of preference after east. Your best bet may be to communicate with local birders to find out what works in your region.
Step 8: Enjoy the Natural Pest Control!
We’ve enjoyed watching birds nesting on our farm and gobbling down our garden pests since 1993. We hope this idea inspires you to invite bug-eating birds to your garden!
All the photos were taken by us on our property. Wildcat Man is responsible for the illustration. Thanks for asking permission before sharing any images.
Step 9: P.S.
Some birds will appreciate a larger house. Medium sized birds such as kestrels, screech owls and flickers will use a house that is about 15" (38cm) deep and about 6" (15cm) square. The entry hole should be about 2" (5cm). Larger birds such as wood ducks and mergansers appreciate a box that is about 18" (46cm) deep and 10" (26cm) square with about a 3" (7.5cm) entry hole. Add a layer of cedar wood shavings about 6" (15cm) deep. These birds do not bring in nesting materials other than their own feathers.
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