STUDIES IN A KANSAS ORCHARD. 29 



already had begun to eat the bark on the trunks of some of the trees 

 and on the low limbs, and to cut the tips of branches and sprouts 

 within their reach. Later, when cold weather set in and snow cov- 

 ered the ground, they also seriously damaged the trees. 



White- footed mice (Peromyscus michiganensis) were especially 

 numerous, but stomach examinations of individuals captured revealed 

 no evidence that they had eaten bark of trees. Skunks, short-eared 

 owls, and marsh hawks were common, no doubt attracted to the 

 vicinity by the abundance of mice. From the large number of partly 

 devoured dead mice found in the burrows during poisoning opera- 

 tions, I had reason to think that shrews {Blarina brevicauda) also 

 were abundant. Of course living voles helped to devour the dead. 



Previous to my visit a force of men and boys had been employed in 

 painting the trunks of the trees with a wash composed of soap, crude 

 carbolic acid, and water. The efficacy of this wash as a preventive 

 of attacks of mice or rabbits did not extend beyond a period of 

 forty-eight hours. 



On the evening, of my arrival I placed wheat poisoned with strych- 

 nine at the base of about 50 apple trees. On the next morning a 

 large number of dead voles and white- footed mice were found. So 

 favorably were the owners of the orchard impressed by the result 

 that a force of men was employed to distribute poisoned grain 

 throughout the orchard. 



The poisoning operations in this orchard occupied several weeks, 

 and by January, 1904, the mice apparently had been exterminated. 

 Rabbits, however, continued to give trouble, and the campaign 

 against them was continued for some time longer, with final success. 



As a treatment for the trees injured by mice, I recommended the 

 immediate covering of the wounds by mounds of soil heaped up 

 around the trunks. The plan was adopted with highly satisfactory 

 results. New bark grew wherever the cambium layer was not eaten 

 completely through, and a great majority of the trees recovered. 

 (PL VI, fig. 2.) Had their trunks been left exposed to the sun and 

 winds of spring and summer most of them would have died. The 

 number of trees actually killed by mice was not very great, although 

 the growth of many was seriously checked. 



Although at first the damages from mice seemed far more exten- 

 sive than those from rabbits, the ultimate losses from them prob- 

 ably were less. The wounds from rabbits were too high up to be 

 successfully covered with soil, and no remedy other than wrapping 

 with paper was tried. The difference in the character of the injuries 

 by these animals is well illustrated by Plate VII, which shows two 

 dead trees — one killed by mice and the other by rabbits. Plate VIII 

 and Plate VI, figure 2, illustrate injured trees in the same orchard 

 which have fully recovered. 



