How to Choose the Best Birdhouse
With all of the birdhouses available on the market, and with so many different woodworking plans for building a birdhouse, how do you choose the best birdhouse for the birds in your yard? Birds are very selective when it comes to choosing a place to nest and raise their families, and they will not take up residence in a birdhouse that does live up to their standards for space, safety, and comfort.
There are Two Basic Types of Birdhouses
- Decorative pieces for display
- Functional nest boxes that are built for birds
Decorative birdhouses are often designed purely for our own visual appeal, and many are not suitable for the nesting needs of the birds. In many birdhouses built primarily as garden art, the entrance hole is too small to allow the birds to enter.
A bird-friendly birdhouse can be functional and still look good in the garden. A nesting box designed to meet the needs of the birds will offer protection from the elements and from predators and provide adequate ventilation with enough room for a growing family. The nest box should open easily for monitoring the nest, and for cleaning after the brood has fledged. Most importantly, the entrance hole must be sized properly: the entrance should be just large enough for the adult birds to enter, but small enough to keep out larger and unwelcome competitors.
Five Key Factors for a Bird-Friendly Birdhouse
Here are several important characteristics to consider when looking for the right birdhouse for your yard:
- The right birds
- The right birdhouse size
- The right materials
- The right height
- A little whimsy
1. Attract the Right Birds
Not every type of bird will move into a birdhouse to build its nest and raise its young. Birdhouses attract certain species of birds, collectively referred to as cavity nesters. Birds that nest in cavities include bluebirds, chickadees, wrens, woodpeckers, and purple martins. Other birds such as robins and cardinals do not build their nests in cavities, and they are not interested in your birdhouses (though robins will occasionally build their nests on a specially designed nesting shelf).
Most cavity-nesting birds cannot carve out their own holes in the trees, and they rely on finding a natural hollow, crag, or an abandoned woodpecker hole that they can call home. In many areas, natural nesting sites have declined significantly due to development and habitat loss, making birdhouses an important resource for the local population of cavity nesters. Many birds will readily move into a man-made structure including bluebirds, titmouse, flycatchers, wrens, nuthatches and flickers, screech and whet owls, kestrels, and even flying squirrels.
2. Make Sure Your Birdhouse Is the Right Size
Birds will bypass a birdhouse that doesn't meet their basic needs, and birdhouses built to the wrong dimensions are one of the most common reasons for an uninhabited nest box. The diameter of the entrance hole, the floor space of the nest box, and the distance from the floor to the entrance hole are all critical considerations.
For most small cavity-nesting songbirds, the floor of the nest box should be at least 4" x 4"; bluebirds prefer a slightly larger 5" x 5" floor. A 1½" diameter entrance hole lets the native birds in, but prevents invasive house sparrows and European starlings from entering. The entrance hole should be positioned at least 5" above the nest box floor.
Bigger Birds Need a Bigger Birdhouse
Different birds have different requirements. While smaller songbirds and bluebirds will nest in a birdhouse built to the specifications listed above, larger birds such as owls, woodpeckers, and wood ducks need more room. Screech owls are common across much of North America, and they will readily move into a nest box with enough floor space and a properly sized entrance hole. The larger barn owl needs an even bigger nest box.
3. Use the Right Materials
A proper nesting box should be well constructed from weather-resistant materials. Pine, redwood, and cedar are common nest box materials that will last for several breeding seasons, and birdhouses made from recycled plastic are becoming increasingly popular. Metal houses can overheat in the sun, and they do not retain the warmth after sunset. Avoid any birdhouses made from treated wood, and do not paint the interior of the nest box.
Shelter From the Storms
A functional birdhouse should have an oversized roof that extends over the nest box and helps to shed rainwater away from the entranceway of the birdhouse. Even with an overhanging roof, some rain is bound to find its way into the birdhouse so the floor needs drainage holes to allow any infiltrating water to escape. Drainage holes in the bottom together with narrow gaps under the roofline increase air circulation through the nest box and help to keep the inhabitants comfortable during the warm weather.
Solid construction is needed to provide the birds with a safe haven from powerful predators such as raccoons. Adding a predator guide over the entrance hole of the birdhouse gives added protection, making it more difficult for hungry hunters to reach into the nest box.
Do not use outside perches; cavity-nesting birds don't need a perch and only the predators and competitors will benefit from a convenient 'handle' to hang on to.
4. Hang the Birdhouse at the Right Height
Hanging the birdhouse in the right spot and at the right height are also important considerations for a birdhouse to attract occupants for a successful nest box. A wood or metal pole with a predator guard is a good choice for mounting a birdhouse, and it should be at least five feet above the ground. Position the birdhouse several feet away from bushes and other places where hunters can hide.
The Right Environment
Attracting the birds into your yard and getting them to stay takes more than just putting out the right birdhouse. A bird-friendly yard should offer several food sources along with fresh drinking water and sheltered areas for security. Create an inviting environment for the birds by adding bird feeders and a birdbath. Native flowers and shrubs produce seeds and berries, and the plants attract a variety of insects to feed both the adult birds and their hungry young.
Whether your garden is large or small, putting up the best birdhouse for the birds might entice a pair to take up residence.
5. Add a Bit of Whimsy
A birdhouse does not need to be plain and boring to be an effective nest box. I built the birdhouses in the accompanying photo to the specifications preferred by eastern bluebirds and other similar-sized cavity-nesting birds including chickadees, titmice, downy woodpeckers, and wrens.
Starting with a basic nest box design made from scraps of pine, I stained the exterior to add some color. A few more scraps, shaped and stained, add a bit of whimsy. Pieces of rusty barbwire or an old horseshoe transform the basic nest box into an interesting piece of folk art. Best of all, these nest boxes will actually encourage birds to move in, build a nest and raise their family.