As use of our forests intensifies, we foresters are paying more and more attention to the agents that damage trees. Much attention has been paid to fire, insects, and diseases. Now we are becoming more concerned about the damage done by animals and birds.
One bird that draws our attention is the yellow-bellied sapsucker. This sapsucker (Sphyrapicus varius varius L.) is a member of the American woodpecker family. It attacks trees to feed on the sap and bark tissues. Its attacks can kill the tree or seriously degrade the wood.
To learn more about this bird, the damage it does, its habitat, and its ecology, the Northeastern Forest Experiment Station has made a 5-year series of observational studies of this sapsucker and its behavior and feeding habits in our New England forests.
Ornithologists whose concern has been mainly with the bird itself reported more than 100 years ago that the sapsucker attacks orchards, shade trees, and forest trees. A few studies, beginning about 60 years ago, have directed attention to the damage done to forest trees.
Our best information dates back to 1911, when McAtee (4) described different kinds of sapsucker damage and summarized what was then known about the sapsucker in the United States. Much of his information was based on studies south of the bird's nesting range. He estimated that sapsuckers damaged at least 10 percent of the trees within their range, and in some areas more than 90 percent of the trees. He reported damage to the wood of 174 tree species.
We can only guess how widespread sapsucker damage is today. But we are beginning to acquire up-to-date information. For example, in 1968 the U.S. Forest Service included evaluations of sapsucker damage among the data to be collected in its forest survey of Maine the first state-wide survey of sapsucker damage.
Sapsuckers not only injure the tree; they also damage the wood. One common kind of damage attributed to sapsucker attack is known as bird peck. Another is the discoloration associated with sapsucker wounds. The literature cited refers to other kinds of damage.
Of the four subspecies of yellow-bellied sapsucker, only one Sphyrapicus varius varius L. occurs in eastern North America (2).
This sapsucker is a migratory bird. It spends the summers on its northern nesting range in the United States and Canada. This range extends from the East Coast nearly to the West Coast, generally between 40 and 50°N. latitude in the East and 52 to 63°N. in the Pacific Northwest. The range also extends southward along the Appalachian Mountains to about 35°N. (2).
This sapsucker's winter range is generally south of 40°N. and as far south as the West Indies and Central America.
Because of this wide migratory range, the sapsucker may attack trees throughout most of North America. At some time of the year this sapsucker or the three western subspecies can be found in all the timber-producing regions of North America.
In New England, sapsuckers can be found on their nesting range from about mid-April till late September or early October. Throughout that period their major foods are tree sap and bark, and insects.
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