Cat owners need to start focusing on their well-loved felines across the nation according to Pete Marra, an animal ecologist with the Smithsonian Conservation Biology Institute. Mara is the co-author for a study released today which reveals that cats are responsible for killing billions of animals.

Yes, the household cat.

(PHOTO: REUTERS/Natalie Behring)Winter, a Norwegian Forest Cat, licks turkey-flavored baby food off a spoon as a reward for good behavior at the "Meet the Breeds" exhibition in New York October 17, 2009. The exhibition featured about 200 breeds of dogs and cats.

The study, printed in the journal Nature Communications, reveals that there is anywhere from 30 to 80 million homeless cats living on the streets. Each of these furry felines is guilty of killing between 23 and 46 birds a year. In addition, those same felines kill between 129 and 338 small mammals during the same time period.

Helping that number along is another 84 million cats who claim owners but are still allowed playtime in the great outdoors. Even after being guaranteed a daily meal, those cats were found guilty of killing between four and 18 birds a year. The numbers are staggering, says Mara, who adds that perhaps its time for cat owners to have a sit down with their felines.

"Listen, Tabby, we're going to have a heart-to-heart talk about how much time you spend outside," Mara told Live Science.

Apparently not only are these felines going out and becoming killing machines, they are also mercilessly cheating on their owners.

"A lot of these cats may go outside and go to 10 different houses, but they go back to their house and cuddle up on Mr. Smith's lap at night," Marra added.