The best birder I know never uses binoculars or field guides. His intense green eyes are as big as his enthusiasm and passion for birds. They don't miss a thing and can detect the slightest movement or suggestion of a bird. I often struggle to get his attention, but he is acutely aware of every winged creature within sight.

His name is Stripe, and he is known by science as Felis catus. Unfortunately, Stripe is not satisfied to simply view birds - he is driven by strong instinct to kill them. A beautiful silver tabby, Stripe has glossy silver fur and a long banded tail.

I keep Stripe indoors at all times because I know that even well fed domestic cats kill thousands of birds over their lifetimes. I also know that by keeping him indoors he will live a comfortable, healthy and longer life. Tragically, such is not the fate for the estimated 60 million outdoor pet cats in the United States.

These cats are vulnerable to wild predators, automobile strikes and are free to kill wild birds. They are frequently exposed to feral cats, which number somewhere close to 100 million and almost always carry serious diseases. Together, pet and feral cats kill 480 million birds in the United States each year.

Fortunately, by just keeping our cats indoors we can save thousands of birds. I truly think many cats are permitted outdoors because their owners don't realize just how efficient a predator their cats really are, but for every bird a cat brings home there are three more left dead somewhere else. In my neighborhood, cat owners place bells on their cats with good intention, but research shows that bells do not work. In fact, a bell can actually mask the sound of a stalking cat.

Ground dwelling species such as robins, wood thrush, ovenbirds and towhees are most vulnerable. Prowling cats killed a family of nesting chipping sparrows in my yard last summer. On another day, I witnessed four cats in the yard hunting simultaneously. One fine looking calico made it a daily habit to sit beneath my bluebird nesting box in hopes of an easy kill. Luckily, the bluebirds abandoned the box and never returned.

Even if a cat doesn't kill, their persistent presence near a nest can stress the bird into exhaustion. Two years back, a large tawny cat turned up below my deck where a pair of robins had built a nest. Every day the cat appeared and stayed around for hours despite the robin's incessant distress calls. The robins dive bombed the cat constantly to no avail. Infuriated, the pair neglected the nest and themselves to ward off the cat. I found the male dead a week later.

Stripe watched all of this with me and a fierce green fire burned bright with envy in his beautiful eyes. I spoke to the vet about his passion for birds and the good doctor assured me Stripe was much better off indoors where he will be safe and healthy for many years. I think the birds will appreciate it, too.

Robert Tougias is a birding author who lives in in Colchester. He is available for presentations and can be reached at rtougias@snet.net.