March 30, 2020
By Keith Sutton
The little screech owl often nests in boxes provided by backyard birders. (Keith Sutton photo)
Many North American birds use nest boxes, everything from tiny chickadees to big barred owls. Our feathered friends benefit when we add boxes to our home landscape because natural nesting cavities often are in short supply. It’s important, however, to be sure we properly design each box so it will attract the birds and protect their eggs and young.
Experts at the National Wildlife Federation say each box should have these basic features:
- Built using natural untreated wood (pine, cedar or fir)
- Lumber for walls that is at least three quarters of an inch thick to provide insulation
- An entrance that is the correct distance from the floor to accommodate the nest
- An extended and sloped roof to keep the rain out
- A recessed floor and drainage holes to keep the interior dry
- Rough or grooved interior walls to help fledglings exit
- Ventilation holes to allow the interior to remain cool
- A side or top panel that opens to allow easy access for monitoring and cleaning
- No outside perches, which aid predators and other harassing birds
It is also important to make sure your box incorporates features preferred by the particular bird species you hope to attract. These features include the proper entrance hole size, the box’s height above the ground when mounted and the type of habitat surrounding the box. For example, if you want to attract nesting screech owls, you need a box with an entrance hole size of three inches placed 10 to 30 feet above the ground in forest habitat.
You can find all this information and more through the NestWatch program of the Cornell Lab of Ornithology. Go to https://nestwatch.org/learn/all-about-birdhouses/ and click on “Right Bird, Right House.” Select your region and the type of habitat around your home (forest, lake, town, etc.). Then you’ll see a list of birds that will use nest boxes in your area. Click again on “see this plan” for the species you’d like to attract, and you’ll find helpful tips and be able to download simple plans you can use to build a nest box at home.