48 THE IMPORTANCE OF BIED LIFE 



habit to alight upon the backs of the victims and 

 with their long hooked bills to burrow through 

 the wool down to the warm flesh. 



So severe has been the damage wrought upon 

 the New Zealand sheep herds by these aberrant 

 parrots th,at a price has been placed upon their 

 heads; and they rightfully deserve the annihila- 

 tion now facing them. Fortunately, the species 

 is confined solely to New Zealand, and does not 

 enter into the economic relations of the rest of 

 the world. 



8 

 The Cash Value of Birds 



It is difficult to arrive at any close estimation 

 of the cash value of birds to agriculture. Many 

 such calculations have been attempted", but most 

 of them leave a wide margin for argument. 

 Probably the most equitable comes from Mr. 

 McAtee, of the Biological Survey at Washington. 

 He figures that each bird will destroy each year 

 insects to the value of ten cents. With a popula- 

 tion of more than four billion birds breeding in 

 the United States, their annual savings to agricul- 

 ture would then amount to at least four hundred 

 million dollars. As insects annually damage ag- 

 ricultural crops in the United States to the tune 

 of more than one billion dollars, it can be seen that 

 birds have an appreciable cash value. 



