A: Sapsuckers, a close relative of woodpeckers, cause damage to trees that is often attributed to wood-boring insects. They visit a tree many times, feeding on sap accumulated in the holes they have drilled. Sapsucker damage appears as rows of holes circling or running vertically on a tree's trunk or larger limbs. This contrasts with emergence holes of borers that occur in a random pattern.
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Contrary to popular belief, these birds rarely, if ever, dig through bark to capture wood-boring insects but rather feed on cambium and sap in the phloem. The tree species most commonly attacked by sapsuckers are pines, sugar maples, birches, willows, magnolias, apples and pecans.
In Oklahoma, the yellow-bellied sapsucker is the most common species that damages trees. They winter in the South and spend summers in the northern part of the United States. Thus, they often cause damage during their migrations in spring through early summer, and again in fall in Oklahoma.
Woodpeckers are classified as migratory, nongame birds and are protected by the Federal Migratory Bird Treaty Act, so killing them is usually out of the question. To protect trees from sapsuckers, wrap barriers of ¼-inch hardware cloth, plastic mesh or burlap around injured areas to discourage further damage.
This method might be practical for protecting high-value ornamental or shade trees. In orchards and forested areas, it may be best to let the sapsuckers work on one or more of their favorite trees. Discouraging them from selected trees may encourage the birds to disperse to others, causing damage to a greater number of trees.
Here are methods that might help deter woodpeckers.
Frightening devices
Visual: Stationary model hawks or owls, fake and simulated snakes, and owl and cat silhouettes are generally considered ineffective as repellents. Toy plastic twirlers or windmills fastened to the eaves, and aluminum foil or brightly colored plastic strips, bright tin lids and pie pans hung from above, all of which repel by movement and/or reflection, have been used with some success, as have suspended falcon silhouettes.
The twirlers and plastic strips rely on a breeze for motion. Large rubber balloons with owl-like eyes painted on them are included in the recent array of frightening devices used to scare woodpeckers. Round magnifying-type shaving mirrors installed near damaged areas to frighten woodpeckers with their larger-than-life reflections have shown promise.
Auditory: Loud noises such as hand-clapping, a toy cap pistol and banging on a garbage can lid have been used to frighten woodpeckers. Such harassment, if repeated when the bird returns, might cause it to leave for good. Propane exploders (gas cannons) or other commercial noise-producing, frightening devices may have some merit for scaring woodpeckers from commercial orchards, at least for short periods.
Because of the noise they produce, they are rarely acceptable near inhabited areas. Around homes, portable radios have been played with little success. Expensive high-frequency sound-producing devices are marketed for controlling various pest birds but rarely provide advertised results. High-frequency sound is above the normal audible hearing range of people and, unfortunately, above the hearing range of most birds, too.
Woodpeckers can be persistent and are not easily driven from their territories or selected pecking sites. For this reason, visual or auditory frightening devices for protecting buildings -- if they are to be effective at all -- should be employed before territories are well-established. Visual and auditory devices often fail to give desired results, so netting might have to be installed.
Repellents
Taste. Many chemicals that have objectionable tastes and odors have been tested for treating utility poles and fenceposts to discourage woodpeckers. Most have proved ineffective or not cost-effective.
Odor. Odors such as from naphthalene (mothballs) and wood treatments such as creosote and pentachlorophenol are of doubtful merit and do not resolve the woodpecker problem.
Tactile methods. Sticky or tacky bird repellents such as Tanglefoot, 4-The-Birds and Roost-No-More, smeared or placed in wavy bands with a caulking gun on limbs or trunks where sapsuckers are working, will often discourage the birds from orchard, ornamental and shade trees. These same repellents can be effective in discouraging birds if applied to wood siding and other areas of structures that are prone to damage.
Some of the sticky bird repellents will discolor painted, stained or natural wood siding. Others might run in warm weather, leaving unsightly streaks. It is best to try the material in a small, out-of-sight area before applying it extensively. Tacky repellents can be applied to a thin piece of pressed board, ridged clear plastic sheets or other suitable material, then fastened to the area where damage is occurring.
Trapping Live traps have been tried to capture woodpeckers for relocation rather than killing the birds. None of those explored were very successful. More research is needed to develop an effective woodpecker live trap. Bill Geer is director of the Oklahoma County Extension Service. His column addresses frequently asked horticulture questions. For more information, call 713-1125.
