UTILITY OF BIRDS. 73 



destroyed by the larva of one of this genus, for several years in 

 succession. 



These facts lead to the conclusion that the robin fairly cams 

 his feast of fruits, by ridding the garden and orchard of one of 

 their most destructive pests. The large quantities of this bibio 

 larva which he consumes during the early spring months, 

 explains in part a certain habit observed in the ways of robins, 

 of scattering themselves singly over the fields and other 

 grounds. The larva of the bibio are gregarious, living together 

 in swarms, perforating the ground, and making it resemble a 

 honey-comb. The parent fly deposits her whole stock of eggs 

 in one spot, and the robin, finding this treasure, resorts to it 

 day after day, until the whole mass is consumed. 



The bibio larva was not found in the food of the robin 

 after the middle of June, but was replaced by a variety of 

 insects and worms ; also, caterpillars, spiders and beetles of the 

 family elateridae — the parents of the well-known wire-worms, 

 so destructive to various kinds of seeds, when committed to tlie 

 ground. The earth-worm was employed by the old birds for 

 feeding their young, but sparingly used for its own food. In 

 the season of cherries and strawberries, these and other pulpy 

 fruits were found intermingled with insects in such proportions 

 as to show that the robin never uses an exclusively frugivorous 

 diet. He employs fruit as a dessert, not as a substantial meal. 

 The mixed diet of the robin continues from the ripening of 

 strawberries until October ; the vegetable part consisting in 

 August and September of the berries of the poke and elder. 

 After this date, he feeds upon grasshoppers and other orthop- 

 terous insects. A few robins linger in our woods after the 

 general migration of the species, when they are often obliged to 

 feed upon winter-berries, especially if the snow has covered up 

 their supply of dormant insects. These and other important 

 facts may be found in Professor Jenk's interesting report. 



I will now proceed to speak of my own experience in regard 

 to the habits of the robin. This bird is not omnivorous ; his 

 food consists more entirely of insects than any other bird that 

 can be named ; for the other large thrushes will occasionally 

 swallow a grain of corn, which the robin has never been 

 known to do. He has been accused of living upon fruits 

 alone, and by others of adding no other article to his feast of 



10 



