THE PACK RAT AS AX ENEMY OF NATURAL REPRODUC- 

 TION ON THE ANGELES NATIONAL FOREST 

 P.v Edward N. AIunns 

 Forest Examiner, Forest Service 



In the late summer of 1915 the attention of the writer was drawn 

 to a number of dead Jeffrey pines (Piniis jeffreyi), the needles of 

 which were just beginning to brown. A close examination of these 

 showed the damage to have been caused by the girdling of the stem 

 by some animal which was supposed at the time to be a porcupine. 

 Later a more detailed examination of the area was made and a number 

 of fresh wounds were seen on both branches and stems of these 

 young pines. In order to ascertain definitdy the marauder a number 

 of steel traps were set at the base of some of the trees and the follow- 

 ing day a large pack rat (Neotoma fiiscipes mohajensis) was taken. 



Smaller traps of the guillotine type were then placed in the 

 branches of several trees which showed fres/h work. That night two 

 more rats were taken, showing fairly conclusively that the work was' 

 that of a rat and not a porcupine. A live rat was caught later and 

 by considerable manipulation several incisions in the tender bark of 

 a small branch were secured. The teeth marks on this branch and 

 those on the pine trees where the damage had been done were care- 

 fully compared under a hand lens and showed indubitable evidence 

 that they were caused by one and the same animal. S. E. Piper, of the 

 Biological Survey, was asked to compare the evidence and he declared 

 this the work of rats. 



To determine the action of the rats and the amount of damage 

 caused, a plot was laid out in this area of chaparral, taking in about 

 a fifth of an acre. All the trees were marked, measured, and examined 

 as to the nature of the injuries and their location. On this area there 

 were 109 trees ranging in height from 6 inches to 25 feet, the largest 

 one having a diameter of 6 inches at the ground, while there were 

 present 13 rat nests of which 4 were uninhabited. It has been found 

 lately by A. F. Taylor, of the Biological Survey, who has conducted 

 careful experiments to determine eft'ective methods for controlling 

 these animals, that but one rat normally inhabits a nest. From the 

 number of inhabited nests there were therefore 9 rats present on the 



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