Birdhouse Maintenance & Safety

Now that you have the correct dimensions for your bird house, take a look at how to make it safe: ventilation, drainage, susceptibility to predators, and ease of maintenance.

Ventilation
Without air vents, boxes can turn into bird ovens. There are two ways to provide ventilation: leave gaps between the roof and sides of the box, or drill 1/4" holes just below the roof.

Drainage
Water becomes a problem when it sits in the bottom of a bird house. A roof with sufficient slope and overhang offers some protection. Drilling the entrance hole on an upward slant may also help keep the water out.

Regardless of design, driving rain will get in through the entrance hole. You can assure proper drainage by cutting away the corners of the box floor and by drilling 1/4 inch holes in the box floor. Nest boxes will last longer if the floors are recessed about 1/4 inch.

Entrance Hole
Look for the entrance hole (and exit) hole on the front panel near the top. A rough surface both inside and out makes it easier for the adults to get into the box and, when it's time, for the nestlings to climb out.

If your box is made of finished wood, add a couple of grooves outside below the hole. Open the front panel and add grooves, cleats, or wire mesh to the inside.

Perches
Never put up a bird house with a perch below the entrance hole. Perches offer starlings, house sparrows, and other predators a convenient place to wait for lunch. Don't be tempted by those beautiful duplexes or houses that have more than one entrance hole. With the exception of purple martins, cavity-nesting birds prefer not to share a house. While these condos look great in your yard, starlings and house sparrows are the only birds inclined to use them.

Accessibility
Bird houses should be easily accessible so you can see how your birds are doing and, when the time comes, clean out the house.

Part of being a responsible bird house landlord is your willingness to watch out for your tenants. Monitor your bird houses every week and evict unwanted creatures: house sparrows, starlings, rodents, snakes, and insects.

Be careful when you inspect your bird boxes. You may find something other than a bird inside. Don't be surprised to see squirrels, a mouse, a snake, or insects. Look for fleas, flies, mites, larvae, and lice in the bottom of the box.

If you find insects and parasites, your first reaction may be grab the nearest can of insect spray. If you do, use only insecticides known to be safe around birds: 1% rotenone powder or pyrethrin spray. If wasps are a problem, coat the inside top of the box with bar soap.

This article was written by the DEPARTMENT OF THE INTERIOR U.S. FISH AND WILDLIFE SERVICE

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