79 



them off their feet, to be killed by other blows. If one escaped 

 into the henpens, boy or dog killed it. This operation was re- 

 peated later from time to time. Four successive battues several 

 weeks apart yielded 152 rats from under and about this hen- 

 house, and no doubt many young rats were drowned in their 

 nests. Where no high-pressure water main is available burrows 

 on the banks of pond, river or ocean might be cleared in this 

 way by means of a powerful sewer pump and hose. 



RAT ENEMIES. 

 Haw'ks, Owls, etc. 

 One cause of the increase of rats is the destruction of their 

 natural enemies by man. In a country where game preserving 

 becomes general, and hawks, owls, weasels and other so-called 

 vermin are killed off, rats often become so numerous and 

 destructive as to be more troublesome than all the other preda- 

 tory creatures. Minks and weasels are far more effective as 

 rat killers than the domestic cat, as these bloodthirsty animals 

 are so thin and snakelike that they can follow the rodents to 

 their nests, where the cat cannot go. Some of the larger 

 hawks ki'll many rats in summer when rodents get out in the 

 fields before dark, and the owls are the most useful of all 

 ratters. The targe owls take full-grown rats, but the smaller 

 species can master only young rats and mice, of which each 

 owl probably destroys many more annually than many cats. 

 Dr. A. K. Fisher of the Biological Survey found about the nest 

 of a pair of barn owls the skulls of 172 brown rats, 452 house 

 mice and 128 field mice. The ground about a barn owl's nest 

 in the Bahama Islands was covered with pellets containing 

 rats' bones and fur. O. E. Niles states that he counted 113 

 dead rats at one time under the nest of a great horned owl.^ 

 Skunks are excellent ratters. A pair which burrowed under- 

 neath a large camp cook house soon cleared it of all rats and 

 mice. If poultry is properly housed, skunks rarely do any 

 damage, and they are very useful about a farm. A family of 

 skunks remained in and about my henyards one season and 



' Treas. Dept., Public Health and Marine Hospital Serv. of U. S., The Rat and its Relation 

 to the Public Health, by various authors, 1910, p. 165. 



