44 BULLETIN 107, U. S. DEPARTMENT OF AGRICULTURE. 



had eaten no less than 5 adults and 40 larvae of Limonius occidentalis. 

 The other more important elements of the animal food were earth- 

 worms (8.68 per cent), flies (5.97), dung beetles (Scarabaeiclae) (5.70), 

 and ground beetles (3.97). Carrion, unassociated with bone frag- 

 ments to denote its origin, was found in several stomachs. The rather 

 careless feeding habits of this bird are attested by a large amount of 

 rubbish in the food. This occurred in 23 stomachs and amounted to 

 nearly 12 per cent of the bulk. A little grain (2.10 per cent) also 

 was eaten. 



For the month of May only four stomachs are available. Each 

 contained the weevil, totaling 7.25 per cent of the food. No very 

 large numbers of the insect were recorded, but this is attributed to 

 the limited amount of material. The other food items maintained 

 approximately the same relative proportions as in April. 



During June a series of 17 stomachs was collected largely about 

 Coalville, in the Weber Valley, where these birds bred in considerable 

 numbers. The weevil, present in 10 stomachs, composed 23.77 per 

 cent of the food, and was taken at an average of about 2 adults and 

 42 larva? per bird. Two birds had eaten exceptionally large num- 

 bers of the insect. One destroyed 2 adults and 253 larvae, and the 

 other 3 adults and about 241 larvae ; the latter composed 80 per cent 

 of the food. Two other noteworthy records were 1 adult and 75 

 larvae, and 5 adults and 40 larvae, respectively. Caterpillars, again 

 a prominent part of the food, were present in all but three of the 

 stomachs and amounted to nearly a fifth of the contents. Ground 

 beetles, darkling beetles (Eleodes), carrion beetles (Silpha), and 

 carrion were the other prominent animal food items. Rubbish, com- 

 prising the bulk of the vegetable element, amounted to more than a 

 fourth of the contents. 



Examination of 18 robins collected in July showed a falling off in 

 the amount of weevils eaten. Eleven birds had fed on the insect at 

 the rate of 4 adults and 13.8 larvae per bird and to the extent of 9.39 

 per cent of the monthly sustenance. One stomach contained 2 adults 

 and about 220 larvae. Caterpillars, still a conspicuous element (37.72 

 per cent), occurred in 12 stomachs. Earthworms made up nearly a 

 fifth of the food, while ground, carrion, and darkling beetles main- 

 tained about the same proportions as in June. The only vegetable 

 food other than rubbish worthy of notice occurred in a single stom- 

 ach, which was filled with the skin and pulp of an unidentified fruit. 



Summary. — As is the case with several other resident species the 

 robin does its most effective work in early spring. Much of its time 

 is then spent about the borders of alfalfa fields, where many weevils 

 are emerging from winter quarters. Though the actual percentage 

 for April (14.29) is less than two-thirds of that for June (23.77), 

 there is no question that the good done is much greater in the earlier 



