This time of year reminds us that Ohio has unpredictable weather. It can be 40 degrees and raining one day, and the next day we need to get out the snow shovel. While I love snow, I also like to plan ahead. One of my spring cleaning chores is to check our bird nesting boxes. Eastern bluebirds (Sialia sialis) begin nesting as early as March, and clean boxes in good condition are important to attracting these lovely insect-eating birds.

The eastern bluebird is a cavity nester, occupying holes in decaying trees and fence posts previously carved out by woodpeckers searching for insects. While Delaware County has only a small percentage of woodlands, and many farmers have removed fencerows for today’s larger agricultural equipment, bluebirds can be enticed to a nest box. Whether you build your own nest box or purchase a ready-made box, there are tips to ensuring success:

• Make sure the nest box is the appropriate size for the eastern bluebird.

• The entrance should face east toward open habitat and be at a height of four to six feet. For the do-it-yourselfer, plans can be found on the Division of Wildlife’s website (ohiodnr.gov) and at The Cornell Lab’s website (allaboutbirds.org).

• If you wish to have more than one box, boxes should be placed 300 feet apart. Alternatively, you can pair boxes 15 to 20 feet apart, with one set 300 feet from the next set. Oftentimes tree swallows (tachycineta bicolor), another beautiful insect-eating species, will locate next door to the bluebirds.

• Bluebirds like grassland (mowed lawns, golf courses, athletic fields, cemeteries and parks) where they flutter to the ground to catch insects. Keep the nest box away from trees, shrubs, and buildings because you will be fighting evil European house sparrows and European starlings.

• House sparrows and starlings, nonnative invasive species, are the bane of bluebirds. They are aggressive, destroying bluebirds eggs and killing the babies, and even the adult bluebirds. Diligently checking the boxes is the best way to deter these pests and it is legal to remove them and their eggs. Another option I plan to try this year is the installation of monofilament to the top and front of the box as shown at ohiobluebirdsociety.org.

• Once the bluebirds have left the nest, clean the box out so it is ready for the next round of egg laying. Bluebirds can raise one to three broods of two to seven eggs each year.

If you are unfamiliar with the eastern bluebird, the male is blue with a rusty throat and chest, while the female is more grayish-blue with an orangish-brown breast. They are in between a sparrow and a robin in size. Watch for them perched on wires or fence posts, or you may sight one flying low to the ground searching for caterpillars, beetles, crickets, grasshoppers and spiders. Bluebirds are not typical visitors to bird feeders except in the fall and winter when you may entice them with suet, peanut hearts, fruit and mealworms.

Eastern bluebird populations dropped in the early 20th century due to the introduction of the European starling and house sparrows. Fortunately, human intervention in the way of nest boxes has helped them recover. If you have the habitat, consider establishing a nest box and experiencing the charm of these little birds.

Check out the Delaware Soil and Water Conservation District’s website and our spring tree and shrub sale at soilandwater.co.delaware.oh.us.