By Christopher R. Tyndall
Since European settlers introduced them to North America, cats have been popular pets. And even after thousands of years of living in close proximity with people, cats haven’t become entirely domesticated as, with their wild instincts, those rogues that wander off from human households manage to live handily in the wild.
But is the independence of cats tempered by their impact on other animals, particularly birds?
An article in the December Bugle by Dave Healy reports the very disturbing estimate that feral and domestic cats might kill as many as 2.4 billion birds annually. This alarming trend comes during an era of unprecedented extinction of many species and frightening reductions of biodiversity. As an exotic, invasive species, felis catus undoubtedly contributes to this process by putting harmful pressure on our nation’s bird population.
As Healy seems to imply, perhaps it is time to confine our pet cats to stop the devastation. This proposal, while worthy of discussion, should spark a broader discussion that goes far beyond cats and birds.
First, let us consider the numbers of wandering cats. Just as parents have become more restrictive over the years in allowing their children to freely wander about their neighborhoods, so too, I believe, pet owners have become more restrictive with their pet cats.
Numerous animal welfare websites report that as many as 75 percent of households with cats keep them indoors. Living in the Como Park neighborhood for over 20 years, I’ve seen raccoons, wild turkeys, coyotes and even deer as often as I’ve seen roaming cats.
As more shelters, veterinary clinics and government agencies educate owners as to the harmful effects and dangers of letting cats roam freely outside, I believe more owners will keep their pets indoors. The humane society certainly advised us to keep the cat we adopted from them indoors. We had every intention of following this advice until our cat herself persisted with her own ideas.
But there is another side to this problem: Even if the apocalyptic numbers of killed birds cited are accurate, is it fair to blame the declining bird populations alone on cats and their alleged uncontrolled hunting activities?
The problem with this view is that the most devastating force in the process of extinction by far, for land-based animals anyway, is not over-hunting, but, rather, fragmentation or complete loss of natural habitat. And for that we can blame, not our wandering outdoor cats, but people for their ever-expanding development of open spaces.
As single-family homes, private automobiles and the necessary infrastructure to connect them all together has become the dominant pattern for U.S. residential development in the US, natural habitat has disappeared.
Let us consider just one facet of this vast, human developed landscape. Parked in our garages is perhaps the most coddled pet of our household: the family car. Automobiles contribute to extinction in a several ways. The most obvious is that automobiles kill animals directly by colliding with them.
The Humane Society estimates that vehicle collisions with animals kill as many as one million animals every day. And these are not just squirrels and rabbits. The Federal Highway Administration reported in 2008 that one to two million large animals are killed each year on roads in the U.S. Both domestic and wild felines are among the victims.
A pet advocacy website tells us that 5.4 million domestic cats are killed each year by cars. But endangered felines in the wild are not spared any less.
A University of Michigan researcher estimated that as much as one half of a modern American city’s land area is dedicated to structures serving automobiles: streets, roads, parking lots, service stations, driveways, signals and traffic signs, not to mention automobile-oriented businesses like automobile dealerships.
But let us focus on birds for a moment, since we normally don’t think of ground-based cars as interfering much with the lives of airborne birds. Surprisingly, the U.S. Fish and Wildlife Service estimates vehicle collisions kill between 80 million and 340 million birds every year. If these numbers are correct, this would suggest that the Humane Society estimate is low and that the total number of animals killed in collisions with cars each day far exceeds one million. But the problem is much more complex than this.
An article in the journal Conservation Biology studied the effects of road networks on bird populations (Conserv Biol, April 25, 2011 (2), 241-9). The article discusses direct effects on bird mortality that we’ve considered above: habitat loss and fragmentation, collisions with vehicles, as well as exposure to airborne pollutants and the other poisonous chemicals that leak from vehicles.
Surprisingly, the authors hypothesize that the greatest harmful impacts might actually result from the indirect and seemingly innocuous effects of vehicles and roads. These include noise, artificial light and physical barriers to free movement. The authors speculate that the two sorts of effects, both direct and indirect, might combine to place further stresses on bird populations. The hunting activities of roaming housecats do not rival the pervasive, disruptive capacity of these ubiquitous features and structures of our developed urban and rural landscapes.
Whether feral or domestic, most cats live in close proximity to human society. As such, they can be considered as an extension of that society. But they are by no means its most destructive element.
It is time to develop far-reaching community and nationwide plans and programs that attempt to counteract some of these other far more harmful forces. Obviously, we can’t uninvent the automobile or force people into high-rise dwellings. But we can continue to develop viable alternatives to automobile transportation, and we can develop neighborhoods so that more of the resources needed for daily life can be found close to home.
We can try to rein in sprawling development and the lifestyle that it promotes. With thoughtful human development, we can better protect and even expand natural habitats and the great wealth of biological diversity they contain. This will help our bird populations far more than keeping our pet cats indoors.
Christopher R. Tyndall is a resident of the Como neighborhood and an occasional contributor to the Bugle.