18 BULLETIN" 107, U. S. DEPARTMENT OP AGRICULTURE. 



bird. The largest number taken by any of this species was 190 

 larvae and 2 adults. Another record was 160 larvae and 2 adults. 

 Three adults and 117 larvae were eaten by one bird, while five others 

 had taken more than 170 individuals apiece. 



Of the other animal food Lepidoptera, in the form of caterpillars, 

 is most important, amounting to nearly 31 per cent. These insects 

 occurred in 15 of the 21 stomachs and in one constituted the entire 

 food. Ground beetles (8.56 per cent), Hemiptera (4.95), weevils 

 other than Phytonomus (4.24), and dragonflies (2.48) made up the 

 bulk of the remainder. The vegetable food (1.2 per cent) was of no 

 economic importance. 



Seven birds collected in July show a decrease in the amount of 

 weevils eaten and a corresponding increase in other food items, as 

 grasshoppers, flies, and grain. Only two had eaten the insect, one 

 having taken but a single adult, while the other had made away with 

 48. Grain amounted to nearly half (44.57 per cent) of the food, 

 verifying the complaint against these birds at this time of the year. 



Summary. — With the exception of the work of adult birds during 

 the month of June, the yellow-headed blackbird can not be considered 

 as among the more effective bird enemies of the weevil, but its uni- 

 formly good work on caterpillars during the entire season argues in 

 its favor. Its strong liking for dragonflies is against it, and also 

 there is little doubt that it lays heavy toll on ripening and shocked 

 grain. 



THICK-BILLED REDWING. 



(Agelaius phwniceus fortis.) 



The thick-billed redwing is a common breeder throughout the Salt 

 Lake Valley wherever is found a clump of cat-tails, a favorite nesting 

 site. As small marshes flank the Jordan River and the shores of Salt 

 Lake, and are about other places where imperfect drainage has left 

 a pool, the bird is fairly well scattered throughout the valley, and 

 of the blackbirds ranks next in abundance to Brewer's. 



Those birds which do not winter in the Salt Lake Valley arrive 

 early enough to render valuable service in the destruction of weevils 

 emerging from hibernation. In the spring of 1912 the writer found 

 them fairly common, and the examination of one stomach secured 

 on the 1st of April indicated that they were already at work on the 

 insects. 



Nestlings. — Thirty of fifty young redwings examined for June 

 had eaten the insect, which amounted to 10.64 per cent of their food, 

 and was taken on an average of 0.3 adult and 12.58 larva? per bird. 

 In several instances, where nesting marshes were situated near in- 

 fested fields, large numbers of larvae were eaten. A brood of three 



