146 BIRD FRIENDS 



ages to kill five birds annually. This would give a 

 total of 23,500,000 birds killed by these town cats. 

 This added to the number destroyed by farm cats 

 gives a total of 99,500,000, or about one hundred 

 million birds killed annually by cats in the United 

 States east of the Mississippi River. 



An estimate may be made of the percentage that 

 this forms of the total bird population. A census 

 taken of the birds on the farms in the United States 

 showed that there was an average of one pair to the 

 acre, making a total of about seven hundred mil- 

 lion birds east of the Mississippi River. If we as- 

 sume that each pair rears to at least partial matur- 

 ity two young birds, there would be approximately 

 a billion and a half birds in this area, of which num- 

 ber, in accordance with the above estimate, about 

 one fifteenth are destroyed by cats. 



The above estimate does not take into account 

 the numerous stray and homeless cats, which in 

 the country doubtless may number as many as the 

 pet farm cats and may do fully as much harm. Mr. 

 Chapman says that there are not less than twenty- 

 five million cats in the United States and that there 

 may be double that number. 



Cats as disease-carriers. One of the reasons 

 why cats are kept is to serve as pets. But even here 

 their value is doubtful, as it has been proved that 

 cats occasionally act as disease-carriers. Sometimes 

 they have the disease themselves and then carry 



