A question has been raised about cats and their prey. Here's what I found out about small rodents. Chipmunks are - relatively speaking - restrained in their breeding habits. They breed twice a year and have 4 or 5 young in each litter. Generally live 3 years in the wild. Deer mice are more active in the population increase stakes. They have anywhere from 1 to 11 pups but usually 4 to 6 in a litter. They breed every 3 to 4 weeks in warm weather. They can get pregnant while nursing the current litter. The young can reproduce at 35 days but more commonly at 49 days. Mortality of young is high, and adults seldom live more than 1-21/2 years. Voles live a short (3 to 6 months on average) but sexy life. Voles reach sexual maturity at 1 month, have a 3 week pregnancy, and anywhere from 5 to 10 litters a year. With 5 to 10 young per litter that's a low of 25 to a high of 100 young per vole per year.Voles are eaten by raccoons, owls, hawks, falcons, coyotes, foxes, snakes, weasels, cats and dogs. And a 2003 study by http://sibleyguides.com/conservation/… of the estimated annual mortality (in millions of birds) gave a figure of a little over 500 million birds killed by cats. Windows, however, killed just under 1,000 million birds.