Bird Houses

Bird houses, also known as "nesting boxes," are a common backyard feature. Some people may have purchased a house from a big-box store only to find that no birds come to it. Many houses that are designed for decoration lack the specifications that birds seek for nesting. 

When you buy a bird house, take these factors into account:

Size. Decide what species you'd like to see nest in your yard and then find a house to accommodate them. Consider these three sizes:

1. The diameter of the entrance hole is important. A 1½-inch opening is common and it may keep out larger aggressive birds like starlings. Smaller birds, like chickadees, will use a house with a smaller opening.
2. Floor space. Birds need a certain amount of floor space so the hatchlings have room to grow. For smaller birds like chickadees, titmice, wrens and nuthatches, a 4-by-4-inch space is sufficient. Larger birds need larger space.
3. Elevation. The entrance height measured from the floor of the box to the bottom of the hole is important for keeping eggs and the hatchlings out of reach from predators.

Heating and Cooling. A bird house needs proper ventilation for heat to escape in the summer. The house should have a slit at the top of a side. Wood should be three-quarters of an inch thick.

Proper Drainage. Make sure there are drain holes in the bottom to let water out. This is important to prevent the buildup of mold and bacteria. The roof should have an inch or two overhang to keep rain from getting in. It is also helpful to face the house in any direction except northwest, which is where most of our storms come from.

Safety. Houses that have a perch look cute but also provide a perch for predators. Natural cavities in trees do not have perches, and birds that use a house don't need a perch either. A metal predator protector around the hole prevents squirrels from enlarging the hole.

Mounting and Access. Your bird house also must reflect your lifestyle. It should be easy to mount and easy to clean out. Houses should have the ability to open for cleaning.

Some houses are mounted against a tree, some are mounted one a pole. Some houses can be hung for wrens or chickadees. Most houses are mounted between 5 and 10 feet above the ground. Bluebirds prefer their houses 4½ to 5 feet high. Some birds prefer houses higher. Purple Martin houses are placed 15 to 25 feet high; woodpeckers up to 20 high; some owls up to 30 feet high.

Placement of the pole is important too. When hatchlings fledge, they are not great fliers, as they have been in the house building their flight muscles but not practicing actual flight. When baby birds leave the bird house, they may fall to the ground to hide under a bush while the parents continue to feed them, or they may flutter to a nearby tree to be fed there while they learn to fly. If you mount the house on a pole, it should be close to a nearby tree or shrub.

Again, determine which birds you want to attract and find the house right for them. Not all birds use these houses, however. For example, goldfinches, cardinals and Mourning Doves build nests in trees, not houses.