Does your cat often convince you to allow him to access outdoors? Are you aware that this opportunity significantly increases the risk of him or her being hit by a vehicle or attacked by a raccoon, stray cat or of him pouncing on a songbird to methodically play with it and eventually savagely kill it? 
Are you aware that cats are the number one killer of many billions of songbirds in Canada and the U.S? 
Further, are you aware that cats can acquire a serious disease called “Songbird Fever” ( Salmonellosis) from the consumption of living and dead birds? 
Does it surprise you that even well-fed cats will still prey on birds because their hunting instincts are so strong that even if they don’t feel like eating them they will still greatly enjoy the excitement of their ” capture- play- with- and- then- kill game”? 
Very unfortunately, fledglings, young birds just out of their nests, are often the easiest targets for cats since they are still learning how to fly and to exist in their world fraught with dangers. 
If any of these points disturb you enough to want to take action here are a few suggestions:
Historically, songbirds have inspired poets, novelists, songwriters, and researchers as well as nature lovers all over the world. It is very sad that globally songbird species are on a decline of the population at an alarming rate. Pollution, loss of habitat and especially predators such as cats are largely responsible for this appalling loss. 
Let’s strive to reduce such devastating losses of many songbird species so that future generations can enjoy what we take so much for granted; the melodious song of birds heralding the onset of spring and summer.