VALUE OF BIRDS TO MAN. 57 



consumed by the young of native Massachusetts birds that 

 are fed almost entirely upon insect food. 



Weed and Dearborn watched three young Cedar Birds in 

 the nest for the fifteen days they remained there, and found 

 that they each devoured not less than ten ounces of food in 

 that time, or more than ten times their weight on the day 

 they left the nest. 



The Amount of Food eaten by Adult Birds. 



There is no way of determining how much food is required 

 daily by the adult bird, except it be kept in confinement ; in 

 that case, the food taken can be weighed or measured. This 

 has been done. Dr. Stanley mentions sixteen Canaries which 

 ate one hundred grains of food per day, or an amount equal 

 to about one-sixth of their weight, which is probably much 

 less than wild birds of the same species would eat.^ Seed- 

 eating birds, like the Canary, however, require less food 

 than the insectivorous species, as their food is more con- 

 centrated. Mr. Eobert Kidgway, the distinguished ornitlaol- 

 ogist of the Smithsonian Institution, makes the statement in 

 the American Naturalist for August, 1869, that a "Western 

 Kingbird {Tyrannus verticalis), which he kept in a cage, 

 devoured one hundred and twenty locusts in a single day. 



Compared with the wild bird, the specimen that is caged 

 or confined is a poor, weak thing at best, short of breath, 

 low in vitality, and lacking the vigorous assimilative powers 

 of the free bird. Keepers of cage birds, who know well 

 the capacity of their pets, find it diiEcult to believe that 

 wild birds can possibly consume the amount of food that 

 actually has been found in their stomachs by economic 

 ornithologists. 



When the reader is told that thirty grasshoppers were found 

 in the stomach of a single Catbird, he conjures up a mental 

 photograph of the full-grown grasshopper (the imago) that 

 he sees in the field in late summer, and fails to remember, 

 perhaps, that grasshoppers come from eggs, and in their 

 growth to maturity may be found of all sizes, between that 

 of the newly hatched insect and the full-winged hopper. 



' History of Birds, p. 225. 



