Our study was designed to find when and how sapsuckers damage trees in this region, and whether they prefer some tree species to others.

Observations for this study were made during five summers, 1964 to 1968. Most of the work was done on our 4,000-acre Penobscot Experimental Forest near Orono, Maine. Some observations were made in other parts of eastern Maine, in northern Pennsylvania, in the Adirondack Mountains of New York, and in New Brunswick and Nova Scotia, Canada.

Ninety-two percent of the observations that were made within sapsucker territories and along a 5-mile sapsucker survey route were made by the observer traveling on foot. Travel on this route totaled 137 miles. The other 8 percent of the observations were made after approaching known feeding trees in an automobile.

Most observations were made at a distance of less than 100 feet. Binoculars were used (7 x 50 or 8.5 x 44).

A bird was considered to be feeding only if its drilling on the tree was intensive enough to produce substantial amounts of sap or bark. Casual pecking around old sapsucker holes was not counted as feeding.

Identifying the sapsucker territory is extremely important in the study of this bird and the damage it does. Sapsuckers establish strong nesting and feeding territories in woodlands during the spring, and stay there until fall. In the spring only one pair will occupy a territory. Later in the summer and fall a family of about six birds (including offspring) will occupy the same territory. They do not move haphazardly about the forest. This permitted intensive study of the birds.

Twenty-seven sapsucker territories were delineated on the Penobscot Experimental Forest. These provided 96 percent of the observations (table 1).

The other 4 percent of the observations were obtained in 49 additional territories: 2 percent were made on other parts of the Experimental Forest; 1 percent were made elsewhere in eastern Maine; 1 percent were made in northern Pennsylvania, the Adirondack Mountains of New York, and in New Brunswick and Nova Scotia, Canada.

Sapsuckers used 47 percent of the Experimental Forest. This was determined by a 12-percent survey of the 4,000 acres in 1966. The 27 territories averaged 7.6 acres. These same territories were occupied for at least three summers (1966-68), and probably for many years before that.

The 27 territories were found by using a new sapsucker calling and surveying technique (F. M. Rushmore, publication pending). It was from 5 to 11 times more efficient than birding techniques commonly used (7).

An important element of this technique is the distinctive drumming used by sapsuckers. It can be used to identify sapsuckers without seeing them. Most drumming occurs in spring. No other woodpecker in this region drums the same way. And as far as I know, no other woodpecker in any region does it the same way, except other sapsuckers (2). The first part of the sapsucker's drumming is a fairly rapid beat (it is generally similar to the complete drumming of other kinds of woodpeckers). Only the sapsucker has the special ending of several more slow, measured taps. A whole sequence might go about like this:

When sapsuckers were observed feeding, these data were recorded: tree species and d.b.h. of trees; area location; bird age and sex; date and time; and other related data. To be included in this report a sapsucker must have been seen actually drilling or feeding on a tree. The only exceptions (1 percent of the 899 observations) were when birds were not present, but daily inspection of trees definitely identified new sapsucker holes.

To obtain the 899 observations (table 1), 535 trees were counted no more than once per day, regardless of the number of times birds were observed feeding. Feeding was observed on 205 days, on 26 tree species and 2 shrub species. Sapsuckers were under observation 650 hours. An estimated 714 sapsuckers occupied the areas when observations were made.

From 1964 to 1968, in consecutive order, the earliest spring observations of sapsuckers on the Experimental Forest were made on 17, 30, 20, 25, and 19 April; the last fall observations were made on 30 September, 7 October, 29 September, 13 October, and 5 October. These dates do not necessarily mean first arrival or last departure.