BIEDS IN RELATION TO THE ALFALFA WEEVIL. gg 



looked. Though its animal food is somewhat less than that of most 

 of its relatives during the summer, in May, June, and July this bird 

 showed a marked preference for the weevil. It was taken more fre- 

 quently than any other food item, and formed about 57 per cent of 

 the animal food. 



WHITE-CROWNED SPARROW. 



(Zonotrichia leucophrys leucophrys.) 



The white-crowned sparrow is a common migrant throughout the 

 Salt Lake Valley and breeds in the higher parks of the Wasatch. 

 The single bird available for this investigation was secured in May, 

 and its stomach contained the remains of one adult alfalfa weevil. 

 Though not an extensive insect eater the white-crowned may assist 

 in reducing the weevil during spring months. 



WESTERN CHIPPING SPARROW. 



(Spizella passerina arisonce.) 



Only eight stomachs of western chipping sparrows are available 

 for examination. One each was taken in May and June, and six 

 in July. Of these only one, a bird collected near Salt Lake City, 

 in May, 1911, had failed to eat alfalfa weevils. This bird had fed 

 almost exclusively on plant lice. The bird taken in June had eaten 

 38 of the weevil larvae, composing 98 per cent of the food, while five 

 lepidopterous eggs made up the balance. Each of the six birds col- 

 lected in July had fed on the insect at an average rate of about 

 1 adult and 17 larva? apiece. These composed 76.5 per cent of the 

 monthly food, and in one instance comprised the entire contents of 

 the stomach, 32 larvae being needed to fill it. The stomach contain- 

 ing the smallest quantity (12 per cent) had three-fourths of its con- 

 tents composed of weed seeds. Of two birds which were evidently 

 feeding young, one had in its bill 6 larvae of the weevil, and the 

 other had 8 larvae and a caterpillar. Of animal food other than 

 weevils, bugs and spiders were most prominent and the vegetable 

 element of 12.6 per cent was entirely weed seeds. 



Too few chipping sparrows were examined to allow a general con- 

 clusion, but its habits apparently justify placing this bird on a par 

 with its close relative, Brewer's sparrow, in its relation to the alfalfa 

 weevil. The larvae of the weevil are suitable both in size and avail- 

 ability as food for a bird of this character. Examination of a larger 

 series of stomachs probably would show that the chipping sparrow 

 feeds on the weevil to the extent of upward of four-fifths of its food 

 during the months of the greatest abundance of the insect. 



