The domestic cat is not a form of 'non-toxic' pest control.  She is an invasive, non-native predator that hunts indiscriminately. 

Domestic cats kill nearly one billion wild birds every year and even more small mammals, reptiles and amphibians. 

Like pesticides, non-target species are affected when cats are used for rodent control. 

For information on how to handle rodent problems in a truly environmentally-friendly and responsible way visit: http://tnrrealitycheck.com/barn_cats.asp.