56 USEFUL BIRDS. 



The number of insects consumed dail>^ by young birds in 

 their nests is difficult of estimation, because of the variation 

 in size among insects and the great difference in size between 

 the mature insect and the newly hatched larva. Five hun- 

 dred of the 3^oung larvtv of a moth might occupy less space 

 in the stomach of a bird than would the moth itself ; while a 

 thousand aphids might take no more room than a full-grown 

 caterpillar. Nevertheless, many estimates have been made, 

 based on known data, as to the number of insects fed to 

 young birds. 



The introduced House Sparrow {Pasf^er domesticus), com- 

 monly called the English Sparrow, undoubtedly eats fewer 

 insects, here, in proportion to the rest of its food than any of 

 our smaller native birds. The young are fed very largely on 

 grain and other non-insectivorous food. Still, a Sparrow's 

 nest in the city of Paris is said to have contained seven hun- 

 dred pairs of chafer wing-cases.^ 



Mons. P. Pelicot gives a table of the estimates, made by 

 several foreign authors, of the numbers of insects eaten by 

 Sparrows in a given time. These approximations vary from 

 that of Blatin, who estimates that two Sparrows will destroy 

 twelve hundred chafers in twelve days, to that of Tschudi, 

 who belie^'es that a single Sparrow will destroy fifteen hun- 

 dred larvje within twenty-four hours. ^ 



Bradley mentions watching a bird's nest and discovering 

 that five hundred caterpillars were consumed in one day.^ 

 He says (according to Sanniels) that a pair of Sparrows 

 will destroy thirty-three hundred and sixty caterpillars for 

 a week's family supplies. A single pair of Sparrows is 

 reported to have carried to the nest five hundred insects in 

 an hour. 



These statements may be exaggerated, but if they approx- 

 imate the facts, what immense numbers of insects must be 



* Notes on Recent Progress of Agricultural Science, by David A. Wells. Re- 

 port (on Agriculture) of the United States Commissioner of Patents, 1861, p. 323. 



^ A Favorable View of the English Sparrow, a Review of " Un Passereau 

 a Proteger," Insect Life, Riley and Howard, Vol. IV, 1891, p. 153, published by 

 the United States Department of Agriculture. 



' Birds and Bird Laws, by J. R. Dodge. Annual Report of the United States 

 Commissioner of Agriculture, 1804, pp. 436, 437. 



