Cats also catch mice , rats , squirrels , lizards , and bugs . In areas where other predators were removed , prey over populated the areas and stripped the land of so much in the way of plants until the areas became drought plagued and rivers dried up , causing starvation for the herbivors , until some predators were reintroduced into those areas . Amazingly , when wolves were reintroduced in public park lands , the plants had an opportunity to grow back , carbon was converted to oxygen , the rivers began to flow again , beavers began building dams again , and nature regained it's balance . I used to enjoy watching the hummingbirds . When a soon to be Momma cat chose to move in with me , I stopped putting out the hummingbird feeders and stopped putting out bird seed . Can't have both in the same areas . They still bring me lizards , but these days the lizards still have all four legs and their tails . The cats call me when they bring a lizard in , I praise the cats , catch the lizards and set them back outside .
Cats kill 1.3 to 4 billion birds and 6.3 to 22.3 billion mammals annually.
Un-owned cats, as opposed to owned pets, cause the majority of this mortality.
Predation by domestic cats is the number-one direct, human-caused threat to birds in the United States and Canada.
So it's NOT wind mills.