PROTECTION OF BIRDS 461 



It was also found that a single species of bird feeds on a 

 great many kinds of insects. For example, the downy 

 woodpecker was found to eat forty-three different kinds of 

 insects ; the robin, two hundred twenty- three kinds ; and the 

 night hawk, six hundred kinds. 



It was further found that many different kinds of birds feed 

 upon some one kind of insect. For example, twenty-six kinds 

 have been found to feed upon the potato beetle, thirty-six 

 kinds on the codling moth (the caterpillar of which is the 

 worm of wormy apples), eighty-eight kinds on cutworms, and 

 one hundred twenty-eight kinds on the click beetles or their 

 larvae, the wire worms. 



Food of nestlings. Nestling birds require vast amounts of 

 food and are fed frequently during the day beginning at 

 sunrise and continuing till sunset. One pair of house wrens 

 was observed to feed its young, two hundred and thirty- 

 eight times in one day. During the two weeks these young 

 were in the nest, they ate from four thousand to five thousand 

 insects. Observations made of many young birds show that 

 it is a common thing for birds to feed their young two hun- 

 dred times in one day, or about once every four minutes. 



One man, after watching a pair of marsh wrens carrying 

 grasshoppers to their young, estimated that the grass- 

 hoppers eaten by all the birds in eastern Nebraska in one 

 day would have destroyed about $1700 worth of crops had 

 it not been for the birds. Another man estimates that the 

 birds of New York State destroy annually more than three 

 million bushels of injurious insects. 



FIELD EXERCISE 9 



Purpose. To see how many times nestling birds are fed in 

 one day. 



Directions. A nest of some bird should be located that can 

 conveniently be watched. The class may be divided into small 

 groups, and each group assigned to watch the birds for a cer- 



