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.1 Seed- 
eating birds, like the Canary, however, require less food 
than the insectivorous species, as their food is more con- 
centrated. Mr. Robert Ridgway, the distinguished ornithol- 
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 difficult 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. 
1 History of Birds, p. 225. 
