DESTROYERS OF INSECT PESTS 65 



place a small tent within arm's length of the nest 

 and watch the bird from within the tent. The birds 

 usually become accustomed to the presence of the 

 tent and come and go as usual. The number of times 

 that the young are fed may thus be learned. The 

 young may be weighed each day, and thus some idea 

 obtained of the increase in weight and of the amount 

 of food eaten. 



Birds in captivity. When birds are kept in captiv- 

 ity the exact amount and kinds of food eaten may be 

 determined. The kinds eaten, under those condi- 

 tions, however, are not a safe guide for determining 

 the kinds eaten in nature, as doubtless, when hun- 

 gry, birds will eat many things which they do not 

 normally eat when at liberty. More accurate esti- 

 mates may be made of the amount of food eaten, 

 as the bird would doubtless require more food when 

 free than when in captivity, so that the amount 

 eaten in captivity would be a minimum. 



Bob-white. The food habits of the bob-white 

 have been studied with birds kept in captivity. 

 Each of the following is a single day's rations: 1350 

 flies, 5000 aphids, 1532 insects, 600 seeds of burdock, 

 12,000 seeds of pigweed, 15,000 seeds of lamb's- 

 quarters. The bob- white was found to eat in cap' 

 tivity 61 kinds of weed seeds, besides the 68 kinds 

 previously recorded, making a total of 129 species. 

 It has also been found to eat 135 different kinds of 

 insects. As a result of these studies it is estimated 



