38 BULLETIN 621, U. S. DEPARTMENT OF AGRICULTURE. 



were obliged to string the top of our poultry range with binder twine (strands 

 2 feet apart), the strands being stretched from division fence to division fence. 

 In no other way were we able to stop the crows killing chickens. (1912.) 



As the majority of reports give evidence that the poultry-stealing 

 habit is one of individuals, it appears that combative and protective 

 measures may be employed with success. The shooting of the. par- 

 ticular marauders has in most cases put a stop to the trouble. Where 

 losses to young poultry and eggs were at all severe, the use of wire 

 netting to cover yards containing chicks and the provision of proper 

 houses for nests have been effective, and the investment has soon 

 paid for itself by the absolute protection afforded. The destruction 

 of a near-by nest frequently prevents further loss to poultry, and 

 crows may be retained throughout the general area to render good 

 service to the farmer. 



For additional control measures see pages 73-80. 



SMALL MAMMALS. 



In the destruction of injurious mammals the crow does work seldom 

 recognized by the average farmer. While individually it may not be 

 so aggressive in its pursuit of a victim as some of the birds of prey, 

 the crow makes up such deficiencies by its greater numbers. The 

 persistence of a squad of the black fellows mobbing a frightened 

 cottontail rabbit or patiently searching grass hummocks for nests of 

 mice early in spring is distinctly corvine. Stomach analysis gives 

 ample proof of this trait, and, while specific identifications can not be 

 made in most cases, the fact that mammals have been eaten is 

 readily proved. Difficulties arise, however, in the distinction be- 

 tween mammal remains eaten as carrion and those secured alive. 

 In identifying carrion among the remains of small mammals the 

 writer relied entirely on the character of the associated insect remains. 

 Necrophagous insects, as Silphidse among beetles and the larvae and 

 puparia of blow flies, most frequently supplied this evidence. 



Mammals comprised 1.64 per cent of the yearly food of the adult 

 crows examined and were eaten in every month. The greatest con- 

 sumption was in April, when such food totaled 4.10 per cent of the 

 diet. In May 3.24 per cent was recorded; in March, 2.77; and in 

 Juty, 2.60. In all other months the percentage was less than 2, being 

 practically nothing (0.05 percent) in September. Mammals occurred 

 in 134 of the 1,340 stomachs, an average of 1 in every 10. Of these 

 remains, injurious rodents formed the major portion. These pests 

 were identified in 82 of the 134 stomachs in which mammals were 

 present and doubtless occurred in many others where accurate de- 

 termination could not be made. In bulk they formed approximately 

 three-fourths of the mammal food, a yearly percentage of 1.22 being 



