THE UTILITY OF BIRDS. 215 



so that we have the result of 1 8,000 caterpillars 

 for the three broods, besides what the old birds 

 eat themselves. 



I have seen a field of wheat nearly eaten up by 

 rats, which swarmed in the banks along the 

 hedge-rows. The landlord was a sportsman, 

 and had ordered his keepers to destroy all ver- 

 min, as they are called, such as stoats, weazels, 

 hawks, owls, &c., forgetting that rats are more 

 destructive to game than any of these, besides 

 injuring his tenant's corn. 



You may have seen, on the Brighton Downs, 

 flocks of chaffinches and other gregarious birds, 

 that is, birds that assemble together, in winter. 

 These do a wonderful degree of good to the 

 farmer, by picking up the seeds of weeds, which 

 would otherwise grow and give him much trou- 

 ble in clearing his land. 



Let us now turn to the swallow tribe, of which 

 we have four species in this country. When 

 they arrive in the spring, you may see them on 

 the wing from early in the morning until late in 

 the evening, busy in catching flies and other 

 insects, which, without the agency of these birds, 

 would increase to a great and injurious extent. 

 You know that hops are planted in rows. Well, 



