The yellow-bellied sapsucker (Sphyrapicus varius), a member of the woodpecker family, is a migratory bird whose summer breeding range includes Texas. The identifying field markings of adult birds are a black crescent on the breast, pale yellow belly, white wing stripe, and a crimson crown. The male also has a crimson chin and throat, distinguishing him from the female whose chin and throat are white.
Although insects make up part of its diet, the sapsucker is better known for its boring of numerous holes in the bark of live trees to obtain sap, the activity from which it derives its name.
The yellow-bellied sapsucker is the only member of the woodpecker family to cause this type of injury. More than 250 species of woody plants are known to be attacked. In Texas they love our oak species and seem to be particularly fond of red oak and burr oak but they love many species of trees and even shrubs.
The sapsucker bores neat rows of 1/4-inch holes spaced closely together through the bark of trees along and around portions of the limbs or trunk. As these holes fill with sap the sapsucker uses its brush-like tongue to draw it out. These holes are periodically enlarged and portions of the cambium and inner bark, together with the fresh sap, are eaten. Puncture wounds and resulting sap flow on branches and trunks of trees are the most obvious symptoms of injury inflicted by the sapsucker.
After repeated attacks on the same area of a tree, large patches of bark may be removed but I seldom see this happen. If this area is girdled, the portion of tree above this point will die. Many small limbs are killed and sometimes the trunk is girdled and the whole tree is killed but not often. Sapsucker feeding on shade and ornamental trees leaves unsightly bleeding wounds that attract bees, hornets, and other insects to the sweet, oozing sap.
Early in the spring the sapsucker tests many trees around its selected nesting site by making sample drillings before selecting ones it prefers. These trees, because of quantity or sugar content of the sap, are visited several times a day for the rest of the season and sometimes are used as a food source for several years.
Feeding wounds serve as entry courts for a wide variety of wood decay or stain fungi and bacteria. On high quality hardwoods, sapsucker wounds cause a grade defect called "bird peck" that lowers the value of the trees. Many forest trees are attacked high in the crowns, making light feeding wounds or sample drillings less evident. A condition known as black bark may develop which results from certain fungi colonizing the sap flow and discoloring the bark, and is good evidence that injury exists.
To discourage sapsuckers from feeding on a favorite shade tree, wrap hardware cloth or burlap around the area being tapped or smear a sticky repellent material, such as bird tanglefoot, on the bark. On large acreage or orchards, leave favorite feeding trees of the sapsucker untreated. Birds will concentrate their feeding activities on these favorite trees, which often protects nearby trees from serious injury.
The Migratory Bird Treaty Act and Federal regulations promulgated under its authority prohibit shooting or trapping of sapsuckers. Shooting of this species would be an ineffective control anyway because transient birds tend to replace occasional losses to local sapsucker populations.
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