164 HABITS OF BIRDS. 



dens. A gentleman who was at the trouble of 

 watching these birds, observed that the parents 

 generally went from the nest and returned with in- 

 sects from forty to sixty times in an hour, and that 

 in one particular hour they carried food no fewer 

 than seventy-one times. In this business they 

 were engaged during the greatest part of the day. 

 Allowing twelve hours to be thus occupied, a sin- 

 gle pair of these birds would destroy at least 600 

 insects in the course of one day, on the supposi- 

 tion that the two birds took only a single insect 

 each time. But it is highly probable that they 

 often took more."* 



Looking at the matter in this point of view, the 

 destruction of insectivorous birds has, in some ca- 

 ses, been considered as productive of serious mis- 

 chief. 



From its sometimes eatrng grain and other seeds, 

 " the rook," says Selby, " has erroneously been 

 viewed in the light of an enemy by most husband- 

 men ; and in several districts attempts have been 

 made either to banish it or to extirpate the breed. 

 But wherever this measure has been carried into ef- 

 fect, the most serious injury to the corn and other 

 crops has invariably followed, from the unchecked 

 devastations of the grub and caterpillar. As ex- 

 perience is the sure test of utility, a change of con- 

 duct has in consequence been partially adopted; 

 and some farmers now find the encouragement of 

 the breed of rooks to be greatly to their interest, 

 in freeing their lands from the grub of the cock- 

 chafer (Melolontha vulgaris), an insect very abun- 

 dant in many of the southern counties. In Nor- 

 thumberland I have witnessed its usefulness in feed- 

 ing on the larvae of the insect commonly known by 

 the name of Harry Longlegs (Tipula oleracea), 



* Anim. Biogr., ii., 282, 6th edit. 



