A primer on maintaining a box for nesting bluebirds

Welcome to February, the prelude to spring.

February is “bluebird month” in Georgia because it’s when the beloved, brilliantly colored creatures start pairing up and checking out nest boxes. Bluebird nesting may commence as early as mid-February and be in full swing by March. In anticipation of that time —- and anticipating the slew of Eastern bluebird-related questions we usually get then —- here is a bluebird primer:

Q: When should I have my bluebird nest box up?

A: Ideally, in Georgia, it should be up by early February, but you can still install one throughout the month of March and even as late as early April. A box is best placed on a post —- not a tree trunk —- 4 to 6 feet off the ground in direct sunlight. Preferred locations are open backyards, meadows, pastures, near fencerows or agricultural fields, and around cemeteries or athletic fields. For more information on erecting and building a bluebird box, visit the Georgia Wildlife Resources Division’s Web site at http: //georgiawildlife.dnr.state.ga.us. Type “bluebirds” in the search box.

Q: What about cleaning out a bluebird box that has been up all year?

A: Clean it out now, before nesting season begins. Once the season commences, wait until the baby birds fledge before cleaning it out again. Bluebirds in Georgia raise as many as three broods a year. After each brood fledges, the parents usually take about a three-week break before starting a new clutch. If a nesting effort fails, however, the birds may try nesting again within a few days.

Q: What about disinfecting a nest box?

A: That’s somewhat controversial, but many experts say it’s acceptable to scrub a box with a 10 percent bleach/water solution. After cleaning, leave the nest box open for a day or so to air and dry out.

Q: If I open the box and find eggs or babies still in it —- or if I touch the eggs or babies —- will that cause the parents to abandon the nest?

A: Unnecessarily disturbing or touching the eggs or babies should be avoided, but if it does happen, the parents will return to the nest. Bluebirds seem to be quite tolerant of human monitoring.

Q: I found several broken eggs around the bluebird nest box and in the box itself. What would cause such a thing?

A: Most likely the culprits are house wrens and house sparrows, both of which are aggressive and will destroy bluebird eggs and take over the nest boxes for themselves. They will enter a nest box, poke holes in the eggs and sometimes eject some or all of the eggs out onto the ground. Remove all the pecked eggs from the box, pick up all eggs and shells from the ground and dispose of them. If any intact eggs remain in the box, leave them for a few days —- the female bluebird may return and resume incubating them. If not, remove the nesting material.

Q: What if I find dead bluebird babies and adults in or around the nest box?

A: Again, the most likely attackers are house sparrows and house wrens. The sparrows will peck nestling bluebirds to death, then build their nests over the corpses. The wrens have been known to remove nestlings and drop them to the ground. (By the way, house sparrows are non-native and therefore not protected by state and federal laws; house wrens are native and therefore under legal protection.)

Q: How do I protect my bluebird boxes from sparrows and wrens?

A: You can remove non-native house sparrow nests from the bluebird box as soon as they are detected. This may have to be done several times, but sooner or later the sparrows will get the message and nest elsewhere. Another option is to move the bluebird boxes away from buildings and bird feeders, which attract sparrows.

Removing active house wren nests can present a problem —- the bird is a native species and therefore it is illegal to destroy an active nest. One suggestion is to mount a separate wren box with a 1-inch diameter hole near shrubbery —- or move the bluebird box farther from shrubbery, which attracts house wrens.

Q: Should I take down my bluebird box after nesting season is over in the fall?

A: No. The boxes make ideal roosts for bluebirds on cold winter nights, such as those we’ve experienced in Georgia this winter.

In the sky

The moon will be first quarter Monday —- in the south at sunset and setting around midnight, says David Dundee, astronomer with Tellus Northwest Georgia Science Museum.

Mercury and Mars are low in the east just before sunrise. Venus shines brightly in the west just after sunset and sets in the west about three hours later.

Jupiter sets in the west just after dark. Saturn rises out of the east about 9 p.m.

seabrk@comcast.net