Attract more nesting birds with these five basics.
By George Harrison, Contributing Editor
There are few bird-watching experiences more rewarding than setting up a birdhouse and having a pair of birds select it as their home to raise young.
Not all backyard birds use houses, including many popular species like cardinals, orioles and goldfinches. But enough common birds do nest in birdhouses to make it worthwhile to set up a few to see what happens.
About 30 bird species in each region of the country are so-called cavity nesters, which means that most of them will also use a birdhouse. Bluebirds, purple martins, house wrens, chickadees, tree swallows and house sparrows are the most common occupants. You might also be able to entice nesters like wood ducks, screech-owls, woodpeckers, titmice and nuthatches.
But setting up a successful birdhouse isn't as simple as "build it and they will come." There are several key factors to consider that will give you the best chance to attract nesting birds.
Select a Suitable Location. Each bird species has different habitat requirements, and this includes the environment they'll choose for nesting.
For example, the best location for a bluebird house is an area facing or surrounded by open fields, where the insects they eat and feed to their young are plentiful. Chickadees are just the opposite. They prefer houses in a thicket or a stand of small trees and shrubs. House wrens like their house to hang from a small tree in a more open yard.
Purple martins select apartment houses placed on a tall pole in the middle of a lawn or open field. And tree swallows want to be close to water where they can find aquatic insects to eat and feed to their young.
Pick the Proper House Design. In addition to specific habitats, different bird species also require varied types of birdhouses.
Purple martins like to live in communities of many birds of their species. Therefore, an apartment-style house or multiple nesting gourds work best. House wrens live in single, small houses, and prefer not to have other wrens close by. Bluebirds require single-room dwellings, typically 50 to 75 yards apart.
Use a Birdhouse That Fits. Generally, small birds need small houses; large birds require large houses. House wrens are happy with an 8-inch-tall house with a 4- by 6-inch base, while a chickadee might select an 8-inch-tall house with a 5- by 5-inch base.
Bluebirds need more room, so a box that's 5-1/2 by 5-1/2 inches and 10 inches tall is perfect. Wood ducks and screech-owls need big houses, 10 by 10 inches and 24 inches high.
Focus on the Front Door. A very important aspect of selecting the right house for the birds you want to attract is the size of the entrance hole. House wrens require the smallest entrance, only 1-1/8 inches. This will also keep out competing nesters, since almost no other birds can fit through such a small opening.
Wood ducks and screech-owls like an elliptical doorway that is 4 by 3 inches and about 20 inches above the floor of the house. The oval-shaped entrance helps prevent predators like raccoons from entering. Chickadees, tufted titmice and nuthatches are comfortable with a 1-1/4-inch hole, while bluebirds need about 1-1/2 inches to get inside.
Get the Height Right. The final factor to consider is that birds prefer their houses at different heights.
Purple martin houses need to be about 15 to 20 feet above the ground. Wood ducks and screech-owls also need lofty homes, 12 to 40 feet high. For bluebirds, like the house at right (photo by Peggy Bruce), hang it 5 to 8 feet above the ground. House wrens prefer them 6 to 10 feet above the ground and hanging from a tree. Chickadees are most likely to nest in houses that are 4 to 8 feet above the floor of a thicket.
No matter what type of birdhouse you use, wood is the best material. The houses also should have ventilation around the top and drainage holes in the floor, and be painted or stained an earth tone. The exception is martin houses, which often are made of aluminum (or dried gourds) and painted white to reflect heat.
Even if you follow these five requirements, not every birdhouse will attract birds. The best way to increase your odds is to offer multiple houses of several types. Then, chances are good you'll have some winged tenants to admire come nesting season.