Issued April 4, 1911. 



United States Department of Agriculture, 



BUREAU OF BIOLOGICAL SURVEY — Circular No. 78. 

 H. W. HENSHAW, Chief of Bureau. 



SEED-EATING MAMMALS IN RELATION TO REFOR- 

 ESTATION. 



By Ned Deakhokn, Expert Biologist. 



The demand for lumber in the United States constantly increases, 

 while the forested area, under the ax of the lumberman, the en- 

 croachments of agriculture, and the devastation by fire, steadily 

 diminishes. Hence the importance of reforesting such parts of the 

 National domain as have been denuded of their forest growth. 



SEED EATERS. 



One of the most serious problems connected with the reforestation 

 of treeless areas within the National Forests is the protection of 

 newly planted seeds from the attacks of mice, chipmunks, ground 

 squirrels, and other rodents (fig. 1), whose depredations collectively 

 continue the year through. The extent of this damage may be under- 

 stood by the results of a reforesting experiment in the Black Hills 

 by the Forest Service, in which from 30 to 70 per cent of the seed 

 was destroyed by chipmunks and mice within six days after planting. 

 In order to get an idea of the abundance of these rodents, exhaus- 

 tive trapping on a half acre containing 2,000 seed spots was under- 

 taken. We secured 3 chipmunks and 11 white-footed mice, which in 

 three days had pilfered 70 per cent of the seed. One of the chip- 

 munks was seen to visit 38 seed spots in four minutes. It will be 

 readily perceived that the destruction of seed on such a scale threatens 

 the practicability of reforestation. 



Accordingly, the cooperation of the Biological Survey was re- 

 quested by the Forest Service for the purpose of devising methods of 

 protecting seeds from destructive rodents. The results of the in- 

 vestigations to date, so far as they relate to seed protection, appear in 

 the present circular. As they were obtained in the Rocky Mountain 

 region, it should be understood that the methods here recommended 



81596°— Cir. 78—11 



