80 FOOD HABITS OF THE GROSBEAKS. 



habits greatly. The once timorous birds leave off their shyness; the 

 isolated families assemble, and flocks, usually small, but sometimes 

 large, raid the grain fields. Oats and rice especially are injured by 

 them. Concerning the effect of the blue grosbeak upon rice in Louis- 

 iana, Mr. George Beyer a says : " In the Florida parishes * * * 

 it is generally called ' rice bird.' Flocks of thousands descend upon 

 the ripe rice during August and September." As noted above, oats 

 were found in 2 stomachs examined during the present investigation, 

 rice in none. 



Summary. — Only 11 of the 51 blue grosbeaks examined had eaten 

 grain, from which it is evident that this food is not specially sought, 

 even when accessible. Grain constitutes 14.25 per cent of the total 

 food, but only one bird ate grain exclusively. Considering only the 

 11 cereal feeders, we find they were satisfied with a fare of half 

 grain, and preferred to eat insects arid other food along with it. It 

 seems, therefore, that in summer this grosbeak does not evince a de- 

 cided taste for grain, and, being widely and sparingly distributed, 

 it is inconceivable that noticeable loss can be caused by it. 



That the reverse is true later in the year is well established, but 

 the injury then committed seems to be of no great importance, or it 

 would have attracted more attention. It is certain that the blue 

 grosbeak is not for an instant to be ranked with such well-known 

 grain pests as the bobolink and some of the blackbirds, and the cases 

 of serious injurj^ attributable to it are clearly of rare occurrence and 

 brief duration. 



Moreover, during by far the greater part of the bird's stay in the 

 United States its food habits are decidedly beneficial, and it con- 

 sumes almost five times as great a bulk of injurious insects as of 

 grain. Without doubt the farmer could afford to pay for the de- 

 struction of these insects with grain in the reverse ratio and yet 

 make a large profit by the bird's services. 



WEEDS, 



Weed seeds are consumed by the blue grosbeak during every month 

 of its stay in the United States. They constitute 18.05 per cent of 

 the total food, and thus are given preference over all other items of 

 the vegetable regimen. Not a great variety of seeds are devoured, 

 and more of foxtail (fig. 37) and bindweed (fig. 21) are taken than 

 any others. It is well known that these weeds are among the most 

 troublesome in America, striving constantly to overtop and crowd out 

 cutivated plants, while bindweed during its earlier stages harbors 

 the corn root-louse, one of the most injurious of grain pests. Prac- 

 tically all birds to any degree vegetarian feed upon the seeds of these 



"Avifauna Louisiana, New Orleans, 1900, p. 34. 



