The topic of this column is a complex one, but before I go into it I’d like to mention that the second Saturday of May is designated International Migratory Bird Day.

First created in 1993 by members of the Smithsonian Migratory Bird Center and the Cornell Lab of Ornithology, IMBD is now directed by the National Fish and Wildlife Foundation and the U.S. Fish and Wildlife Service. It is a celebration of an incredible natural phenomenon – bird migration – as well as a call to awareness, action, and conservation of birds.

Another organization committed to identifying and addressing critical issues of bird populations is the American Bird Conservancy. One of their biggest campaigns is “Cats Indoors!” Its focus is to educate all cat owners about the devastating effects their cats have on birds and other wildlife, and to convince them that keeping their cats indoors is the best thing for birds, people, and the cats themselves.

I knew this would be a contentious issue when I chose to write about it. I knew some people might think I’m condemning cats and cat owners, but that is far from the case. I am a cat owner myself, and think they’re the best pets anyone could have (the key word here is pets).

I got an inkling of one reaction I might get when I talked to a co-worker about the necessity of keeping cats inside the house.

“If you keep cats inside, they’ll no longer be cats,” he said, nonplussed.

I was equally baffled by his statement; and was at a loss as to how to effectively reply. Now, I wish I had said they’ll no longer: be hit by cars; be carriers and transmitters of disease; harbor infestations of parasites; acquire bite wounds and develop painful abscesses; or be tortured by warped and sadistic people. As a former veterinary technician, I’ve witnessed the cruel things people have done to cats, which seem to be the recipients of this type of treatment more often than other animals.

I think my coworker was uncomfortable at the thought of preventing what comes naturally to cats: stalking and hunting. Yes, this is what they were created to do – as are other carnivores, dogs included – but it doesn’t mean we can, or should, allow them to do so. They are our domesticated pets, and therefore our responsibility. They are not wild.

The American Bird Conservancy relates these sobering statistics: there are approximately 73 million pet cats in the United States, 48 million of which are outdoors some or all of the time. In addition, there are an estimated 60 million to 100 million feral cats roaming free. Scientists believe birds constitute between 20 percent and 30 percent of the prey of these free-ranging cats.

Bird populations are also being threatened by habitat loss and degradation, pollution, and collisions with communication towers and other structures. The U.S. Fish and Wildlife Service estimated that communication towers kill four million to five million, and as many as 40 million, birds yearly.

They’re getting hit from all quarters. Cats might not be the only problem, and, some say, the biggest problem; but if a solution exists, why not try it?

To find out how to transition your outdoor cat into a contented indoor cat, or how to handle neighbor’s cats that invade your yard, visit the American Bird Conservancy Web site: www.abcbirds.org/cats/. You can also write Linda Winter, director of the Cats Indoors! Campaign, at: American Bird Conservancy, 1834 Jefferson Place, NW, Washington, D.C. 20036.

Chris Corio, a volunteer at Fields Pond Nature Center in Holden, can be reached at fieldspond@juno.com