124 NATURE-STUDY 



Mention should also be made of guano, which is a very 

 valuable fertilizer, and is the accumulated manure of sea 

 birds found on many islands in dry climates, especially off 

 the Peruvian coast. 



Another economic aspect of the birds is seen when we 

 consider the harm that certain birds do. Many species en- 

 tail a loss to man by injuring his crops, or feeding upon his 

 fruits, or by robbing him of domesticated animals or of game. 

 Blackbirds and crows are great grain and corn thieves, and 

 when they gather in flocks of thousands in a farmer's 

 field, they do great damage to the freshly sown grain, or 

 dig up the planted com, or shell out the heads of the 

 standing crop. When troublesome this way they are de- 

 servedly shot. The bobolinks, so famous in poetry and so 

 harmless and cheering in the North, become a veritable pest 

 in the southern rice fields, where they spend the winter in 

 vast flocks. Here they are shot and eaten by the negroes 

 and others. The cedarbird, catbird, thrush, and robin 

 do considerable damage to small fruit, such as cherries and 

 berries. The Baltimore oriole has a bad habit of pecking 

 open the pods of green peas. Farmers and gardeners try to 

 protect themselves by shooting the thieves or by setting up 

 scarecrows, which, however, are generally useless. Crows, 

 hawks, and owls steal poultry, and occasionally they thus 

 cause great annoyance. 



On the other hand, practically all birds feed upon insects, 

 and many destroy other harmful creatures or such as are 

 considered a nuisance. In this way man derives a great 

 indirect benefit from the birds. This is not realized as 

 thoroughly as it should be, or it is often forgotten, while 

 at the same time only the sins of the birds are remem- 



