142 The Pocket Gopher. 



gopher is not so likely to be pushing a load of dirt when he en- 

 .counters the steel trap in the dark. As between covering the 

 trap itself or leaving it uncovered, I should recommend the 

 latter plan. In a series of 100 tests we carefully covered one 

 trap in each case with tissue paper and fine earth and left the 

 other exposed. The per cent, of catch was so nearly the same 

 that the slight difference in favor of the covered trap would not 

 warrant the expense of extra time required to set the traps in 

 this way. In fact, later experiments, performed when the 

 .ground was wet from recent rains, gave the poorer results for 

 the covered trap, on account of the jaws clogging. As the 

 gopher in his underground tunnels must be guided entirely by 

 the sense of smell and of feeling, there could be no particular 

 advantage in concealing the trap with a thin covering of earth. 

 This practice has no doubt arisen from similar methods em- 

 ployed in trapping animals that live above ground. 



It seems to me, therefore, that the most practical and effi- 

 cient method of using the steel trap is to simply open the bur- 

 row at some point, introduce the trap and completely cover the 

 opening you make with sods, a bunch of hay, or perhaps a 

 board anything that is convenient and will exclude all light. 

 Vary the method of setting the trap if the animal keeps filling 

 it with earth. Placing the trap vertically in the runway, with 

 jaws down, will sometimes give good results. We have never 

 tried baited traps of any sort. I believe, however, from the 

 evidence of a few experiments, that one may increase the per 

 cent, of catch by covering the opening above the trap with 

 freshly cut alfalfa. 



Traps designed especially for the pocket gopher have the 

 advantage, over the steel trap, of being more easily and quickly 

 set and of killing the animals at once instead of holding them 

 by the leg for hours. Some of them also have given us a higher 

 per cent, of catch than the steel trap. Of the five different pat- 

 terns we have tested, all are built on pretty much the same 

 lines. They are intended to be set at the end of a lateral, and 

 are so constructed as to throw when the gopher pushes a load 

 of earth against the trigger. A choker or a pair of sharp 

 prongs does the rest. In setting any of these traps a ray of 

 light must be admitted to the burrow through a small opening, 

 so as to attract the attention of the gopher and cause him to 

 come with a load of earth to stop up the hole. The trigger in 



