DESTROYING RATS. y41 



DESTROYING RATS. 



The Biological Survey has made both laboratory and field experi- 

 ments with various agencies for destroying rats. The results obtained 

 form the chief basis for the recommendations set forth in the following 

 pages. • 



TRAPS. 



Owing to their cunning it is not easy to clear premises of rats by 

 trapping. A few adults refuse to enter the most innocent-looking 

 trap. And yet trapping, if persistently followed, is one of the most 

 effective ways of destroying the animals. For general use the 

 improved modern traps with a wire fall released by a baited trigger 

 and driven by a coiled spring have marked advantages over the old 

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

 traps, sometimes called guillotine traps, are of many designs, but the 

 more simply constructed are to be preferred. Probably those made 

 entirely of metal are the best, as they are more durable and are less 

 likely to absorb and retain odors. 



In illustration of the effectiveness of traps it may be related that 

 about three years ago a large department store in Washington expe- 

 rienced heavy losses of gloves, lace curtains, and other merchandise 

 from rat depredations. After they had made many unsuccessful 

 attempts to abate the nuisance, the managers were advised to try the 

 improved traps. As a result 136 rats were killed during the first 

 20 nights, when the losses practically ceased, and trapping has been 

 continued in the store ever since with satisfactory results. 



Guillotine traps should be baited with small pieces of Vienna 

 sausage (Wienerwurst) or fried bacon. A small section of an ear of 

 corn is an excellent bait if. other grain is not present. The trigger 

 wire should be bent inward to bring the bait into proper position to 

 permit the fall to strike the rat in the neck, as shown in the illustra- 

 tion (fig. 2). 



Other excellent baits for rats are oatmeal, toasted cheese, toasted 

 bread (buttered), fish, fish offal, fresh liver, raw meat, pine nuts, apples, 

 carrots, corn, and sunflower, squash, or .pumpkin seeds. Broken 

 fresh eggs are good bait at all seasons, and ripe tomatoes, green cucum- 

 bers, and other fresh vegetables are very tempting to the animals in 

 winter. When seed, grain, or meal is used with a guillotine trap, it 

 is placed on the trigger plate, or the trigger wire may be bent outward 

 and the bait sprinkled under it. 



When rats are numerous, the large French wire cage traps can be 

 used to advantage. They should be made of stiff, heavy wire, well 

 reenforced. Many of those sold in hardware stores are useless, 

 because a full-grown rat can bend the light wires apart and escape. 



