94 GROUND AND WATER ENEMIES 



any alarm. The gamekeeper quickly would destroy his 

 cat and replace it with another if it exhibited any 

 disposition to eat birds. Good cats I regard as ex- 

 ceptional. All the cats I have ever owned destroyed 

 birds daily. 



Rats undoubtedly are among the worst enemies of 

 ducks. Captain Oates says they are the worst.^ He 

 took sixteen wild duck eggs from one rat hole. Fryer 

 disposes of rats in five words, "Rats must be cleared 

 out."2. 



The common brown rat was introduced in America 

 about the year 1775, and despite the incessant warfare of 

 man, it has extended its range and steadily increased in 

 numbers. Its dominance is due to its great fecundity 

 and its ability to adapt itself to all sorts of conditions. 

 A compilation of all the methods of destroying rats prac- 

 ticed in historic times would fill a volume. One of the 

 most effective poisons for rats is barium carbonate, or 

 bayrites.8 



Mr. Lantz, who prepared the bulletin cited, says the 

 improved traps with a wire fall released by a baited trig- 

 ger and driven by a coiled spring (sometimes called guil- 

 lotine traps) have a marked advantage over the old 

 forms, and many of them may be used at the same time. 

 The traps should be baited with small pieces of Vienna 

 sausage (wienerwurst) or bacon. 



Mr. Lantz, in a second bulletin prepared for the Bio- 

 logical Survey, United States Department of Agricul- 



1 "Wild Ducks." 2 "Country Life Lib. Sport, Vol. I., Shooting, p. 135. 

 3 "Methods of Destroying Eats." Farmers' Bulletin 297, tJ. S. Dept. 

 Agr. This bulletin can be had upon application to the tJ. S. Agricul- 

 tural Department, Washington, D. C. 



