Vol. XXXIl 

 1914 J 



Bryant, Birds as Grasshopper Destroyers. 



171 



by other investigators as well as some performed by the writer 

 show that insects such as grasshoppers are digested by birds in 

 from three to four hours. Consequently the number of grass- 

 hoppers destroyed each day must be at least three times the num- 

 ber found in a stomach. 



The following table gives the results of the stomach examinations. 

 In spite of the comparatively few stomachs of each species examined 

 the results should give a fairly accurate idea of the extent to which 

 birds in the infested areas were feeding on grasshoppers. 



Considering the capacity of the bird, the Burrowing Owl (Speo- 

 tyto cunicularia hypogoea) must be considered the most efficient 

 destroyer, twenty-eight grasshoppers having been found in the 

 one stomach examined. Blackbirds and Meadowlarks however, 

 exceeding in numbers of individuals, were probably doing the most 

 effective work. 



The comparative destruction of grasshoppers per day by single 

 individuals and by the total number of each species is crudely 



COMPARATIVE DAILY DESTRUCTION OF GRASSHOPPERS 



BY BIRDS. 



Species 

 Anthony's Green Heron {Butorides virescens 



anthonyi) 

 Killdeer {Oxyechus vociferus) 

 Burrowing Owl (Speotyto cunicularia hypogcea) 

 Arkansas Kingbird {Tyr annus verticalis) 

 Black Phoebe (Sayornis nigricans) 

 California Horned Lark {Otocoris alpestris 



aclia) 

 Bicolored Red-wing {Agelaius gubemaior cali- 



fornicus) 

 Western Meadowlark {Sturnella neglecta) 

 Bullock's Oriole {Icterus hullocki) 

 Brewer's Blackbird (Euphagus cyanocephalus) 

 English Sparrow (Passer domesticus) 

 Cliff Swallow (Petrochelidon lunifrons lunifrons) 

 California Shrike {Lanius ludovicianus gamheli) 

 Destruction per square mile by total bird 



population 



120,453 



