April 5, 2008
Bluebird boxes can bring enjoyment to bird lovers
Nesting activities begin early for the beautiful and beneficial bluebird, a voracious insect eater that can bring a splash of color and a lyrical song to many homesteads.
If you haven't done it already, now is the time to clean, repair or put up new homes for bluebirds, one of our most beloved wildlife species, said Laurel Barnhill, wildlife biologist and statewide bird conservation coordinator with the S.C. Department of Natural Resources (DNR).
"Each pair of bluebirds can produce up to two or three broods per year," Barnhill said. "Adults start looking for a nesting cavity in February or early March, so there's no time to waste in getting nest boxes built and in place, or in cleaning out existing boxes." Bluebirds cannot construct their own nesting cavities, as is the practice of woodpeckers. If cleaning boxes now (early April) and nesting material looks "fresh," new feathers, materials, even eggs, do not remove materials as this indicates that this box is in use.
For more information on bluebirds or for nest box plans, write Bluebirds, DNR Wildlife Section, PO Box 167, Columbia, SC 29202 or call (803) 734-3886 in Columbia.
In the mid-1960s, people discovered that a simple bird box of proper dimensions in the right habitat could aid in reversing the bluebird's population decline, which was likely caused by pesticides, the widespread development of rural land after World War II, and competition from house (English) sparrows and starlings.
Bluebird numbers in the state and nation have been climbing in recent years. "During the past 20 years, thousands of bluebird boxes have been put up across the country, and this simple, inexpensive and rewarding hobby has probably been responsible for much of the turnaround in bluebird numbers," Barnhill said.
Grasslands and large open areas near forest edges are ideal for bluebird habitat. Since bluebirds do not nest in woods or deep shade, place boxes in open areas with scattered trees, away from buildings. Pastures, large lawns, cemeteries and golf courses are good locations. Bluebirds prefer close-cropped grasslands with limbs, wires or other perches from which to spot insects.
"Because bluebirds are territorial, bluebird boxes should be placed at least 100 yards apart," Barnhill said. "Boxes can be placed closer together if you want to attract chickadees, wrens or titmice, because bluebirds won't defend their territory against other species of birds." The round entrance hole of the bluebird box should be no larger than 1.5 inches in diameter to prevent starlings from entering.
When mounting bluebird boxes, a smooth metal post such as a galvanized pipe, rather than a wooden post, offers better protection from predators such as cats, raccoons and snakes. A galvanized pipe threaded at one end can be obtained from a hardware store and attached to the bottom of the box with a pipe flange.
Coating the post with soft grease while bluebirds are nesting may help to deter predators, but attaching a predator guard below the box is best. A 15- to 18-inch-wide strip of aluminum flashing wrapped around the post may also work. Set boxes about 4 feet above the ground or at eye level, and about 25 to 100 feet away from a tree, shrub or fence to help young birds survive their first flight by providing a safe landing place.
One of the most rewarding aspects of maintaining bluebird houses is periodically inspecting them during the nesting season, according to Barnhill. At least once a week, check each box for nest building, eggs or young. Tap on the side to allow the bluebird on the nest to exit before opening the box. By taking notes on the eggs and young, bluebird enthusiasts will learn how long it takes for the nest to be built, for eggs to hatch and for young to grow large enough to leave the nest.
After the young bluebirds have left their nest for good, clear out the old nest to increase the chances for second and third broods being raised in the same box. To discourage parasites that live in nest material, spread on the bottom of the box a layer of diatomaceous earth, a natural material that is abrasive to insect exoskeletons.
DNR protects and manages South Carolina's natural resources by making wise and balanced decisions for the benefit of the state's natural resources and its people.