FIELD MICE AS FARM AND ORCHARD PESTS. 



9 



Cultivation destroys weeds and all the annual growths that serve as 

 shelter for the animals. This applies equally well to orchards and 

 nurseries. Clean tillage and the removal from adjoining areas of the 

 weeds and grass that provide hiding places for mice will always secure 

 immunity to trees from attacks of the animals. 



PROTECTING NATURAL ENEMIES OF MICE. 



Field mice are the prey of many species of mammals, birds, and 

 reptiles. Unfortunately, the relation that exists between the numbers 

 of rodents and the numbers of their enemies is not generally appre- 

 ciated; otherwise the public would exercise more discrimination in its 

 warfare against carnivorous animals. It is the persistent destruction 

 of these, the beneficial and harmful alike, that has brought about the 

 present condition of growing scarcity of predacious mammals and 

 birds and corresponding increase of rodent pests of the farm, espe- 

 cially rats and mice. The relation between effect and cause is obvious. 



Among the mammalian enemies of meadow and pine mice are 

 coyotes, wildcats, foxes, badgers, raccoons, opossums, skunks, weasels, 

 shrews, and the domestic cat and dog. Among birds, their enemies 

 include nearly all the hawks and owls, storks, ibises, herons, cranes, 

 gulls, shrikes, cuckoos, and crows. Among their reptilian foes are 

 black snakes and bull snakes. Not all these destroyers of mice are 

 more beneficial than harmful, but the majority are, and warfare 

 against them should be limited to the minority that are more noxious 

 than useful. 



OWLS AND FIELD MICE. 



Owls as destroyers of mice are deserving of special mention. Not 

 one of our American owls, unless it be the great horned owl, is to be 

 classed as noxious. Especially beneficial are the short-eared, long- 

 eared, screech, and barn owls. All these prey largely upon field mice, 

 and seldom harm birds. Unfortunately, the short-eared and barn 

 owls, which are the more useful species, are not plentiful in the sections 

 most seriously infested by field mice. 



The short-eared owl, while widely distributed, is not abundant, 

 except locally, within the United States, but wherever field mice be- 

 come excessively numerous these owls usually assemble in consid- 

 erable numbers to prey upon them. Examinations of stomachs of 

 these owls show that fully three-fourths of their food consists of short- 

 tailed field mice. 



The barn owl is rather common in the southern half of the United 

 States and breeds as far north as the forty-first parallel of latitude. 

 That mice form the chief diet of this bird has been demonstrated by 

 Dr. A. K. Fisher, of the Biological Survey, through examination of 

 stomachs of many barn owls and also of large numbers of pellets 

 (castings from their stomachs) found under their roosts. In 1,247 



