2019-02-08 / On Second Thought

S.C. Bluebird Society provides guidance for luring sky-colored avians

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Compiled by Warren Hughes

How can I learn more about attracting bluebirds?

As naturalist writer Henry David Thoreau once said, the bluebird carries the sky on his back and anybody who spots one in the garden is made happy by the sight. For those who want to learn more about these precious winged creatures, fly right over to the website of the South Carolina Bluebird Society at southcarolinabluebirds.org. For details about membership, contact President Mike DeBruhl at cmdebruhl@southcarolinabluebirds.org.

The state society is dedicated to the recovery and conservation of the Eastern Bluebird and other cavity-nesting birds native to South Carolina and elsewhere. Established in Aiken in 2010, the SCBS is the first North American Bluebird Society affiliate in the state. Because the society website is such a splendid resource, we are quoting excerpts directly below (go to website for complete information):

As early as the end of February and as late as June, the male bluebird locates a nesting site, establishes territory around it of two to five acres, and sings to attract a female and warn other male bluebirds to stay away. Once a female accepts the site, she builds a neat cup shaped nest of dry grasses and pine needles. Nest building may take five days to three weeks.

The female lays one blue, or rarely white, egg each morning until three to six eggs are produced. The female begins incubating the eggs after the final egg is laid. Thirteen to fourteen days later, all eggs will hatch with hours of each other.

The adults begin feeding the young immediately after hatching, starting with soft insects and graduating to courser food as the nestlings grow. … The nestlings grow very rapidly, with theirs eyes opening on about the eighth day. By the time the nestlings fledge (leave) the nest box 16-20 days after hatching, they will be nearly the size of an adult bluebird.

Usually the entire brood of fledglings leaves the box within two hours. The fledglings can fly fifty to one hundred feet on their first flight and try to land in a bush, shrub or low branch to avoid predators.

The adults continue to care for the young and teach them to forage for food. The male bluebird will continue this job while the female begins her second or third nest. On occasion, the young from a first nesting will help feed the nestlings from their parents' second or third nesting.

After nesting season is over, bluebirds give up their territories and flock together. South Carolina bluebirds do not migrate. They are joined by migrant northern bluebirds and roam the area looking for berries. In winter, bluebirds will roost in pine tree stands and nest boxes to avoid cold weather.

Loss of habitat and growth in competition

Between the 1920s and the 1970s, the bluebird population declined by an estimated 90%. There are a number of reasons for this, but the main ones are loss of habitat and competition from other species.

The main source of competition for bluebirds is a bird that is not native to North America - the House or English Sparrow. The House Sparrow was introduced to this country in the mid-1800s. It was thought that this bird would help control insect pests; however, those that brought them here seriously underestimated this bird's fiercely competitive nature. The House Sparrow population exploded, while that of the bluebird declined alarmingly. … Another source of competition for the bluebird is the Eastern Starling, a bird that is equally aggressive and will also kill both bluebird adults and young.

Suitable location

Bluebirds prefer to nest in an area that includes open space, scattered trees, and low ground cover such as lawns, golf courses, pastureland, parks, school, and industrial campuses. They do not nest in heavily forested areas. They also do not like land that is completely open (no trees or shrubs), but one that still provides perches for hunting (such as fences, telephone lines, posts, shepherd's hooks, etc.) and trees nearby for both shade and to offer the baby birds a safe destination for fledging. Care should be taken not to place the nest box so close to trees and fences, which predators are afforded easy access to the box from above. Keep boxes at least 200 yards from barnyards and feed lots where House Sparrows are abundant. Avoid areas with heavy pesticide use. Bluebirds are territorial, so multiple boxes should be placed at least 100 feet apart as a rough guide. Vegetation and topography might make closer location possible. There should be no direct line of sight between multiple boxes.

Proper Nest Box

Purchase or build a nest box designed specifically for bluebirds. Preferably, these are made of unpainted cedar, redwood, cyprus or pine. If you must paint your nest box, it should be painted ONLY on the outside, in a very light color, to avoid overheating. The box should have an overhanging slanted roof, NO perch, and a round entrance hole 1- 1/2” in diameter. It should have ventilation and drainage holes, be deep enough so predators can't reach in to get to the eggs and have a door that opens for ease of monitoring and cleaning. In areas of intense heat, additional measures should be taken to avoid overheating, such as the use of 3/4” lumber, and overhanging roof on all sides, and placement in a location that receives shade from the afternoon sun.

Mounting

Nest boxes may be mounted at any time, but to attract bluebirds for their first nesting of the season, they should be in place by mid-March, depending on your geographic location. You may see nest boxes mounted on trees, wooden fence posts or metal poles. SCBS highly recommends mounting nest boxes on a metal or plastic pole with a predator baffle to deter critters such as snakes and raccoons:”

Metal poles may be difficult for predators such as snakes and raccoons to climb. A metal mounting post need not be elaborate or expensive. Smooth, round 1" electrical conduit is inexpensive and works well; although any smooth scrap round pipe will work. The next box should be mounted on the post so that the entrance hole is five feet off the ground.

Monitoring

Nest boxes should be monitored at least once a week to be sure that undesirable competitors are not sing them. They should also be monitored for blowflies, ants, and other parasites, and predator problems. Bluebirds readily tolerate humans monitoring their nest boxes. They will not abandon their young because humans have looked at or touched them. Bluebirds do not have a good sense of smell, so your scent on their nest will not disturb them. Care should always be taken when opening a nest box, especially once the hatchlings are 12 days old, as this could cause them to fledge too early. The nest box should be cleaned out after each brood of babies has fledged. Bluebirds will not reuse a nest. They will typically produce three broods of three to six young by from March to August in South Carolina.

Feeding

It is not normally necessary to feed bluebirds; however, many people find they enjoy offering treats to their birds, both to help them through times of difficulty, and to have the opportunity to interact more closely with these gentle, trusting creatures. They eat insects and insect larvae and berries. Some common native berry bushes that bluebirds enjoy are: Flowering Dogwood, Holly, Juniper, Sumac, Mountain-ash, Mistletoe, Hackberry, and Firethorn. Another food commonly offered to bluebirds is mealworms. They can be purchased in bulk from several mail-order houses, or obtained locally at bait shops, and wild bird supply stores. During winter months, bluebirds will come to suet feeders and seed feeders containing sunflower meats. One caution is if you like to feed other species of birds - do not place your bluebird nest boxes too close to your wild bird feeding area. Feeding seed “blends” containing corn, milo, and millet, or feeding stale bread, rolls, or donuts will attract house sparrows to your yard and endanger your bluebirds. Bluebirds also enjoy shallow birdbaths, especially those with a drip/misting feature.

The Columbia Star wants to add to the community’s storehouse of knowledge, whether it is a neighborhood matter, a larger issue or a simple curiosity. We’ll do the footwork for you. Submit your questions to: wmchughes27@gmail.com.

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