191-] Brijaiit: Relation of Biids to a Grasshopper Outhrcalc 11 



busily engaged in catching grasshoppers. At times these flocks 

 were seen at a considerable distance from their usual habitat. 

 They appeared to feed almost wholly in the infested districts, 

 and more often in alfalfa fields than in pasture land. 



Brewer blackbirds were occasionally seen about ranch houses. 

 Their numbers were few compared with the red-wings. The 

 insectivorous Jial)it of this bird cannot be judged from the one 

 stomach available. That this species fed on grasshoppers to a 

 larger extent than did the red-wing can be safely concluded 

 from the results of other investigations. In an investigation of 

 a butterflj' outbreak in northern California (Bryant, 1911). it 

 was found that Brewer blackbirds fed on the butterflies to a 

 far greater degree tlian did the red-wing, which, under the 

 circumstances, appeared to be largely a vegetarian. 



One of the most important things which came out in the 

 investigation was the evidence that at least one of the herons 

 and one of the shore-birds had turned their attention to the 

 insect most abundant. An Anthony green heron, collected along 

 a canal, contained fourteen grasshoppers. One hundred per cent 

 of the food of a killdeer was made up of grasshojipers, eleven 

 having been eaten. The killdeer, being a common liird in the 

 locality, and having a greater capacity than smaller birds, must 

 be considered an effective destroyer. 



The stomach of a great blue heron found dead beneath an 

 electric power line, contained no grasshoppers, but did contain 

 two gophers [Thomomys angularis), still undigested. It is 

 evident, therefore, that this bird must require at least the equiva- 

 lent of two gophers a day, for the time of digestion cannot be 

 more than six hours. The testimony of the ranchers of the 

 State also indicates that the great blue heron is one of the best 

 known gopher destroyers. 



The California shrike, or butcherbird, seems to have some- 

 thing of a preference for crickets {Gryllus), for although this 

 insect was comparatively uncommon, yet the two stomachs ex- 

 amined contained a total of six of these insects, as well as parts 

 of eight grasshoppers. 



Stomach examination of two English sparrows collected in a 

 wheat field showed plainly their food preference for grain. Al- 



