This morning I walked outside to call my dog back inside and found her eating a dead bird. Now, I realize that birds die all the time, but this is not the first time this has happened. Every-other-day or so I chase a cat out of my yard, sometimes with a chipmunk in its mouth. People who know me know that I am an animal lover, but this does mean that I have to tolerate an ecoterrorist just because it is a friendly feline.
Every year in the United States between 6.3 billion and 22.3 billion mammals fall victim to the bloodlust that every cat is born with (www.nature.com.) The domestic cat is even listed at number 38 on the Global Invasive Species Database's top 100 list of Invasive Alien Species. While cat's largest impact is on islands they clearly must have a large impact on the rest of the continental United States, since only one state is an island in its entirety– Hawaii.
Most people simply do not realize the damage that pets can have on the environment. If it were a dog it would be deemed dangerous and unacceptable for it to be running free on anyone's property without its owner present (and not only is it unacceptable, it is considered illegal as well.) But if a pet cat– considered property– causes damage to a neighboring property it is the cat's owner who is legally responsible for replacement of the item damaged or monetary compensation.
In some states, it is part of vaccination laws and animal control laws for cats to be labeled with a name tag and spayed or neutered. If someone picks up a pet cat and has no way of identifying whose cat it is not only is the cat regarded as an unprotected invasive species, it is likely the cat will be taken to a county shelter or given to animal control. This is the importance of chipping pets, because if that cat– who was not wearing a name tag or any other form of identification– was taken to the shelter and it had a chip, the shelter can immediately check the owner's info and contact them to come pick the cat up. If the cat (or any pet that gets lost, for that matter) is not chipped and is not wearing any identification the shelter legally only has to wait between 24 and 72 hours until they can euthanize the animal, depending on the local laws.
I understand owners can have many reasons for allowing pet cats to free roam: exercise, the cat "gets bored," no need for a litter box or even, the owner is "allergic." First off, if you are allergic to cat dander, then why did you get a cat? That was simply irresponsible on your part and should not be taken out on the natural species that inhabit the area around your dwelling.
Cats genuinely do not need much exercise, and it is possible to keep them in shape indoors. With adjustments to their diet and some cat towers, toys, a laser-pointer, and a box the cat can not only be kept healthy but also entertained (even when the owner is not home.)If the owner doesn't like cleaning a litter box or can't stand the smell they could put the pet cat on a leash and take them for a walk or train them to use and flush the toilet. There are also self-cleaning litter boxes available and litter formulas are improving every year.
Just because you have a pet and it just so happens to be a cat does not exempt you from thinking about the environment. You are not exempt from caring about your neighbors' feelings. Newsflash: just because neighbors don't complain to or about you doesn't mean they're not bothered by their dead potted plants, the smell of cat feces pervading the air, and "murder-presents" left on the doorstep. It's not hard. It doesn't take a drastic lifestyle change to allow the life of the countless birds and small mammals to continue. Garfield can be just as happy watching the birds from indoors, your neighbors will be much happier when they no longer have to clean up your pet's mess, and you will be much happier knowing that you are possibly saving the lives of both your cat and the local wildlife.
Sources:
http://www.iucngisd.org/gisd/100_worst.php
http://www.nature.com/ncomms/journal/v4/n1/full/ncomms2380.html