BREWER'S BLACKBIRD 317 



including 51 adult and 9 nymphal grasshoppers in 30 stomachs; the 

 other ten stomachs held 16 field crickets." Bryant (1912) lists the 

 Brewer's blackbird as a feeder on grasshoppers during an outbreak 

 of these insects in California, but says that it does not rank among 

 the most important predators, judged either by the number of insects 

 per day each bird eats or by the number of birds eating the grass- 

 hoppers. He concludes that the value of birds in controlling such 

 insects is greater during the periods of normal insect numbers than 

 at times of extraordinary abundance. Bryant (1911) found the 

 Brewer's blackbird to be an efficient destroyer of the butterfly Eugonia 

 calif ornica during an outbreak in northern California in 1911. 



Several authors have reported caterpillars in the diet of this species. 

 Munro (1929) observed them feeding on "forest tent caterpillars" at 

 Rollins Lake, British Columbia. McAtee (1922) reports the taking 

 of canker-worms by this blackbird at three places in California where 

 the worms were threatening prune crops. 



The corn earworm (Heliothis obsoleta) has been accused of being 

 "the most destructive insect enemy of corn in the United States" 

 and one of the most important of the 17 species of bird to feed on 

 this pest is the Brewer's blackbird, according to Phillips and King 

 (1923). 



This species was seen by Murie and Bruce (1935) associating with 

 western sandpipers (Ereunetes mauri) which were feeding on the brine 

 fly Ephydra millbrae along a road traversing the mud flats on San 

 Francisco Bay. The blackbirds also were "almost certainly feeding 

 on the flies." Bond (MS.) found Ephydra hians as an item in the 

 diet of this bird at Moss Landing, Monterey County, Calif., in 1931 

 and Ephydra sp. at Owens Lake, Calif., in 1938. 



The Brewer's blackbird is considered by Kalmbach (1914) to be an 

 effective enemy of the alfalfa weevil. Howell (1906) says: "Four 

 species of blackbirds are known to consume boll weevils [in Texas}, 

 the most important of which seems to be the Brewer's blackbird." 



Emlen (1937) says: "Blackbirds have frequently been accused of 

 stealing almonds; but although three species, Brewer (Euphagus cyano- 

 cephalus), Bicolored (Agelaius phoeniceus), and Tricolored (Agelaius 

 tricolor) were all common in the orchards, there is no definite evidence 

 that they were feeding on almonds during the preharvest months." 

 Beal (1948) writes: 



During the cherry season in California the birds [Brewer's blackbird] are much 

 in the orchards. In one case they were observed feeding on cherries, but when a 

 neighboring fruit grower began to plow his orchard almost every blackbird in the 

 vicinity was upon the newly opened ground close after the plowman's heels in its 

 eagerness to secure the insects turned up. 



The laboratory investigation of this bird's food covered 312 stomachs, collected 

 in every month and representing especially^thejruit^andjjrain sections ofsouthern 



