POOD OF NESTLINGS. 43 



POOD OF NESTLINGS. 



The largest consumption of insects is to be credited, not to adult 

 birds, but to young ones in the nest. All land birds at Marshall Hall 

 except birds of prey and doves, whatever be their own diet, feed 

 their young chiefly on insects from the time they are hatched until 

 they leave the nest. Many species rear every season two or three 

 broods of from 3 to 5 each, and so voracious are these wide-mouthed 

 youngsters that the parents can su])ply their wants only by unremit- 

 ting efforts. Meals often begin before sunrise and continue till after 

 sunset, frequently occurring everj^ two minutes. At iirst nestlings 

 take considerably more than their own weight of food in a day, and 

 they increase in weight daily from 20 to 50 percent. The number of 

 insects required to supply a season's host of nestlings must be almost 

 incalculalple. 



Work of other investigators. — One can best study the food of young 

 birds by field observations. Such studies have been pursued by Mrs. 

 Wheelock," Dr. Francis H. Herrick,* and Prof. Clarence M. Weed.'^ 

 Professor Weed's bulletin on the feeding habits of nestling chipping 

 sparrows has already been cited at length in Bulletin 15 of the 

 Biological Survey. Dr. Herrick found young cedar birds fed by 

 their parents on grasshoppers, cicadas, chokecherries, raspberries, 

 and blueberries. A brood of red-eyed vireos were given blackberries, 

 red raspberries, bugs, beetles, larvse, katydids, and grasshoppers. 

 Nestling catbirds were nourished with red cherries, strawberries, 

 larvse, moth millers, beetles, and dragon-flies {jEschna heros and Lihel- 

 Ivla pulcJiella). Young bluebirds were fed robber-flies (Asilus), larvae, 

 crickets, grasshoppers, and katydids. Mrs. Wheelock states that she 

 observed nestling red-headed woodpeckers eating black beetles; that 

 marsh wrens bring May-beetles to their broods; that young robins are 

 fed moths and dragon-flies, and that crows give frogs and nestling 

 birds (English sparrows, song sparrows, and meadowlarks) to their 

 young. 



Methods of investigation. — Mrs. Wheelock's excellent lesults were 

 obtained in the field by observing the nests in situ, and Dr. Herrick's by 

 cutting the nests down and placing them in a favorable situation for 

 observation. Both of these methods have been employed at Marshall 

 Hall. The choice of glasses is important. Mrs. Wheelock used binoc- 

 ulars in studying her subjects. These were used at Marshall Hall 

 with the best success in the case of very active shy birds or those in 

 shadow. A Zeiss monocular 12-power was tried, but was found to 

 be useless unless there was an abundance of strong sunlight, and 



a Nestlings of Forest and Marsh, 1902. 

 6 Home Life of Wild Birds, 1901. 

 cBuU. 55, N. H. Agr. Expt. Sta., 1898. 



