37 



known to destroy other forms of this moth, and I have exam- 

 ined two localities where birds are believed to have actually 

 extirpated small colonies of this insect. 



Decrease of Birds followed by Increase of Destructive Insects. 



Samuels tells us that Frederick the Great, fond of cherries, 

 ordered the destruction of sparrows which were stealing his 

 favorite fruit. A price was set on their heads throughout 

 Prussia, and the war against them was carried on successfully. 

 At the end of two years there were no sparrows, but neither 

 were there any cherries; and most other fruits also were want- 

 ing. The trees swarmed with caterpillars, lacked leaves, and so 

 produced little fruit. Insects had increased to an alarming 

 extent, since other birds had been killed or driven away by 

 the drastic measures employed against the sparrows. Finally 

 the King revoked his decree, but also felt obliged at consider- 

 able expense to import birds to take the place of those de- 

 stroyed. 1 



In 1798 the forests in Saxony and Brandenburg were ex- 

 tensively attacked by a lepidopterous insect that bored into the 

 wood and killed the trees. This became so general a calamity 

 that expert foresters and naturalists were sent by the regency 

 to inquire into the cause. From their report it became ap- 

 parent that the extraordinary increase of this insect and the 

 consequent destruction of the trees was due to the absence for 

 years of several species of woodpecker and titmouse. 2 



Reaumur asserts that in 1826 the great trees along that 

 noble avenue, the Alle Verte, at Brussels, were nearly deprived 

 of leaves by the caterpillars of the gypsy moth. In the autumn 

 the moths swarmed like bees; they were very abundant in the 

 park, and if one-half their eggs had hatched there would not 

 have been a leaf left in 1827. Two months later, however, 

 hardly an egg could be found. The extirpation of these eggs 

 was attributed to titmouses, creepers and other small birds which 

 abounded in the park and were known to eat the eggs of these 

 insects. 3 



Annual Report, Massachusetts State Board of Agriculture, 1865 (1866), pp. 116, 117. 

 * Flagg, Wilson: The Utility of Birds, Annual Report, Massachusetts State Board of Agri- 

 culture, 1861 (1862), Abstract, pp. 66, 67. 



Kirby, William, and Spence, William: Entomology, 1846, p. 152. 



