28 BULLETIN 107, U. S. DEPARTMENT OE AGRICULTURE. 



is especially adept at hulling even the hardest and smallest of seeds, 

 the partly digested embryos gave no clue as to their identity. 



The house finch may render some service in checking the increase 

 of the weevil by destroying adults early in the season, but owing to 

 its almost exclusively vegetarian diet this must be small. Whatever 

 worth this species has lies in its consumption of weed seeds. 



PINE SISKIN. 



( Spinus pinus. ) 



The stomach of the only pine siskin examined contained traces of 

 an adult alfalfa weevil, but from what is known of its food habits 

 in other parts of its range, this bird can not be regarded as important 

 as a weevil destroyer. It is primarily a seed eater, and its animal 

 food is confined mainly to such forms as plant lice and scale insects. 



WESTERN VESPER SPARROW. 



{Pocecetes gramineus conflnis.) 



The western vesper sparrow arrives in the Salt Lake Valley in 

 March, when, during cold, blustery days, it may be found often in 

 parties of three to six flitting about weed patches, usually not far 

 from the protecting cover of a creek bottom. Later in the season 

 it is a common breeder in the sagebrush areas adjacent to cultivated 

 fields, and from here it makes regular trips to alfalfa fields in search 

 of the weevil. 



In April, 16 of these birds were collected in alfalfa fields. All 

 but three had fed on adult weevils, which amounted to about a twelfth 

 of the food. The small size of the stomachs means that in numbers 

 the weevil will be limited. An average of a little less than two adult 

 weevils per bird was maintained for this month, while eight weevils 

 is the highest record of a single bird. 



Other investigators have shown that the food of this bird varies 

 from wholly vegetarian in midwinter to upward of 90 per cent ani- 

 mal during summer. In Utah insect life began to form an appre- 

 ciable portion of the food in April, and amounted to a little less than 

 a quarter of the stomach contents. A third of this was the alfalfa 

 weevil. Of the other items the clover-root curculio (Sitones sp.) 

 occurred frequently and totaled about 4 per cent of the contents. 

 Fourteen of these were found in one stomach. Dung beetles (ApJw- 

 dius) formed about an equal amount, while the remaining animal 

 food was divided in small quantities under several heads. Of the 

 vegetable food (76 per cent) about 19 per cent was grain and 57 per 

 cent weed seeds. The latter element was present in all but one of 

 the stom&chs and in four instances formed practically the entire con- 



