SHALL WE PAY OUR DEBT? 361 



six inches in length. The warbler young must 

 have insect diet. Their crops are large for the size 

 of the birds, and the old birds keep them packed 

 all day long. A young warbler can eat over half 

 its own weight in insects each day and handle them 

 conveniently. 



One ornithologist kept record while a palm 

 warbler collected from forty to sixty insects a 

 minute to carry to its young. He estimated that 

 the bird he was watching from his veranda took 

 over nine thousand insects in four hours. Of 

 course these insects were very small, but so are the 

 wheat midge and Hessian fly; yet they do millions 

 of dollars worth of damage to the wheat crops of 

 one season. Scientists who have made an especial 

 study of the work of warblers while insect collect- 

 ing have kept record as a yellow-throat took eighty- 

 four birch aphis to the minute. A chestnut-sided 

 warbler made a record of twenty-two gypsy cater- 

 pillars to the minute, and the more agile Nash- 

 ville warbler ahnost doubled this record by taking 

 forty-two. Another chestnut-sided warbler took 

 twenty-eight caterpillars in twelve minutes, and a 

 black-and-white gathered up his twenty-eight in 

 ten minutes. A Maryland yellow-throat collected 

 fifty-two caterpillars in a short time. All warblers 

 eat tent caterpillars, apple tree tent, brown tail, 

 and gypsy caterpillars, all pests of the worst de- 

 scription on fruit trees and other vegetation. 



The tiuy host comes winging to us exactly at 



