Birds and Forest Vegetation 503 



fresh, recent work. This girdling was very thorough and it is 

 remarkable that the tree was not dead. No. 3 was dead with dry 

 leaves attached. It was 2.5 inches in diameter 4 feet above the 

 ground. The girdling began over 5 feet above the soil and extended 

 upwards about 3 feet, but was mainly concentrated. No. 4 was 

 dying, as its leaves had begun to turn slightly yellow. It was 

 2.2 inches in diameter 4 feet above the ground; girdling (old) 

 began at 4 feet 8 inches, the fresh work began at about 5 feet, 6 

 inches, and extended up the trunk about 20 inches, and above the 

 concentrated old injury there was an enlargement of the trunk. 

 This detailed character of the injury on each of the tree trunks 

 is shown in figure 153. The older injury was in general lower 

 down on the trunk than the newer. The birds working on these 

 trees were very tame (figure 154), and pounded away within 10 

 to 15 feet of me, so that the light-colored chips could easily be 

 seen falling as their work progressed. Occasionally they were 

 seen to act as if picking insects from the trunk, and one was 

 observed to leave the tree, and flycatcher-like, attempt catching 

 insects on wing. One very warm day the birds were observed to 

 hold their mouths open as if panting, as poultry sometimes do 

 when overheated. The amount of bark and wood removed at my 

 visit to the trees seemed slight, and it was only by watching the 

 work from day to day that the progressive extension of the injured 

 area became clearly evident. 



At the Camp a large-toothed aspen (Populus grandidentata) 

 overhung the lakeshore, on w r hich there were numerous sapsucker 

 holes in 1915. The general character of the injury is well shown 

 in figure 155, where a two-foot rule serves as a scale in the illus- 

 tration. This was the only example of this tree found showing 

 injury. In August, 1916, additional freshly bored scattered holes 

 were noted on this tree. 



Near the colony of aspens, which were injured so much (figure 

 148), were two excellent examples of sapsucker injury to large 

 trees of yellow birch {Betula luted). They stood near the lake- 

 shore in an open burned area. The general character of the injury 

 on one tree is well shown in figure 156, which reveals the scat- 

 tered holes near the base of the tree and up the trunk to near the 

 lower branches. The concentration of the injury here into vertical 

 rows is characteristic. On such large trees the bark is very thick 

 so that the cavities produced are about a third of an inch deep, 

 and were deeper when the tree was alive. The healthy look of the 

 tree shown in the figure indicates that it had not been injured 

 seriously. A near view of this injury is shown in figure 157. On 

 the other hand, another tree of the same kind near by had been 

 killed by the repeated attacks (figure 158). Some parts of the 

 trunk are weathered and darker stained than other parts, which 

 may be due to a difference in age or to the flow of rain-water down 

 the trunk. A careful examination of the trunk shows no evidence 

 of healing, a fact that suggests a concentrated attack and rather 

 early death. A more detailed view of the trunk is shown in fig- 

 ure 159. 



