54 WOODPECKEES IN RELATION TO TREES. 



species in the United States, of which 248 are known to be punctured 

 by sapsuckers. Thirty-eight introduced species are attacked, which 

 belong to 17 families, 3 of which have no native representatives. 

 Sixty-three of the total number of trees and shrubs are seriously 

 damaged by sapsuckers and 31 of them, besides 1 vine, are known to 

 be killed. There are 31 families of plants having native arborescent 

 species in this country, and 7 wholly introduced families, no member of 

 which is known to be attacked by sapsuckers. However, these fam- 

 ilies average less than 2 species each, while the native f amilies, includ- 

 ing the 258 species attacked, contain an average of 14 species each, 

 so that our negative results for the former group are probably due in 

 great part merely to the small amount of material examined rather 

 than to the sapsuckers' distaste for trees of these families. 



Indeed it seems probable that practically all trees accessible to 

 sapsuckers will sooner or later be attacked. The only widespread 

 and numerous trees not yet known to be punctured are the mul- 

 berries, Osage orange, and figs (family Moracese), and the palms and 

 yuccas belonging to the endogenous subclass of plants, in which the 

 circulation of sap is peculiar, which are presumably unsuited to 

 sapsuckers. 



The evidence shows that the three species of sapsuckers have prac- 

 tically the same habits and consequent injurious effects upon trees. 

 However, the Williamson sapsucker is not now known to harm trees 

 of great value. Leaving this species out of consideration and speak- 

 ing only of the red-breasted and yellow-bellied sapsuckers, the above 

 detailed testimony abundantly confirms the conclusion drawn from 

 the anatomical structure and stomach examination, namely, that 

 sapsuckers habitually feed upon bast, cambium, and sap. It further 

 shows that in securing their favorite food they often remove so much 

 of the growing layer of trees that the vigor of the latter is impaired, 

 sometimes to such a degree that death ensues. 



However strong seems the indictment against the sapsuckers, it 

 must not be imagined that every tree pecked by them is doomed. On 

 the contrary, they frequently work on a tree year after year without 

 noticeably diminisliing its vitality. Near Washington the writer has 

 noted large elms whose trunks have evidently been attacked by many 

 generations of sapsuckers ami are freely drilled every year, but which 

 to all appearances are now in perfect health. W. A. Taylor, of the 

 Division of Pomology in the Department of Agriculture, states that 

 at lus home in southwestern Michigan there are several apple trees, 

 now over 70 years old, which are known to have been yearly drilled 

 by sapsuckers without diminisliing their vigor or productiveness. The 

 western half of the Department of Agriculture grounds at Washington 

 contains 232 trees, of which 56 have been attacked by sapsuckers. 



