BIRDS OF PREY 29 



Ravens, crows, and jays do effective work in destroying 

 pests. Occasionally, however, when they have increased 

 out of proportion to the food supply available, they 

 become troublesome by killing small chickens and by 

 destroying the eggs and nestlings of wild birds." 



From the same source I quote an incident showing the 

 results of interfering with the balance of Nature. 



" An extensive marsh bordering a lake in northern 

 New York formed the suitable home for numerous ducks, 

 rails, snapping turtles, frogs, and other aquatic life. 

 The turtles deposited their eggs in abundance in the 

 sand of the old beach. These delicacies attracted the 

 attention of the skunks of the neighbourhood, and their 

 nightly feasts so reduced the total output of eggs that 

 only a small proportion of the young survived to reach 

 the protective shelter of the marsh. As time went on 

 conditions changed. Skunk fur became fashionable, and 

 commanded a good price. The country boy, ever on the 

 alert for an opportunity to add to his pocket money, 

 sallied forth and captured the luckless fur-bearer wherever 

 found, so that within a comparatively short time the 

 skunks almost wholly disappeared. When this check 

 on their increase had been removed, the snapping turtles 

 hatched in great numbers and scrambled off in all directions 

 into the marsh. When their numbers had been properly 

 controlled by the destruction of a large proportion of 

 their eggs, their food supply was adequate, but when they 

 increased many-fold the supply proved insufficient. 

 Finally, through force of circumstances, the turtles 

 added ducklings to their fare until the few ducks that 

 refused to leave the marsh paid the penalty of their per- 

 sistency by rarely bringing to maturity more than one 

 or two young. It is not surprising that this gieat 

 aggregation of turtles, containing the essential of delicious 



