Feral Cats

Feral cats are domestic cats that were born in, or have reverted to, a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural environments. There are 25 to 60 million feral cats just in the United States. They usually live in colonies, occupying a specific territory with a source of food. A grass roots effort to humanely reduce the feral cat population is called 'trap-neuter-return'. Cats are trapped, neutered, immunized and then released. Volunteers continue to feed and care for the cats throughout their lives. An established colony helps to prevent other feral cats from moving into an area.

The Truth About Feral Cats

The topic of feral cat predation on wildlife, especially birds, has become a battleground of competing opinions on whether feral cats should be trapped, neutered and returned to their environment, or if they should be viewed as invasive species and eradicated. A careful analysis of the science concludes there is no strong support for the viewpoint that cats are a serious threat to wildlife, except in certain instances of fragile populations in isolated or fragmented ecosystems.

Hundreds of news outlets reported on a Smithsonian Conservation Biology Institute and U.S. Fish and Wildlife Service study in 2013 claiming “free-ranging domestic cats kill 1.4 to 3.7 billion birds and 6.9 to 20.7 billion mammals annually” in the U.S. The absurd estimates presented in the study of bird mortalities represented 28.5 to 75.5% of the estimated 4.7 billion landbirds in all of North America. If these figures were even remotely accurate, birds would have been wiped out in North America long ago. A careful examination of the mathematical model developed by the researches revealed one inflated input after another. Yet, this bad science continues to be quoted over and over again by the media and wildlife organizations.

Too often, very flawed science is used to wrongly blame cats for declining wildlife populations and to bolster the false case against Trap-Neuter-Return. The so-called “Wisconsin Study” is one of the most misquoted and misunderstood of these studies. It is not reliable scientific research. The Wisconsin Study is not even a real study—in fact, it is a proposal for a study that never actually took place. The Wisconsin Study’s “data” has never been peer-reviewed, and only parts of it have been selectively published.

The authors published several articles attempting to project the potential impact of free-ranging cats on the bird population in the state of Wisconsin. The authors themselves identify their estimates of cat predation on birds as guesses. When interviewed about the estimates of cat predation from the study, one of its authors, Dr. Stanley Temple, disavowed them, saying, “Those figures were from our proposal. They aren’t actual data; that was just our projection to show how bad it might be.”

As this false data circulates, people aren’t getting the truth about wildlife and cats. The American Bird Conservancy, the U.S. Fish and Wildlife Service, and other groups have carelessly wielded these flawed statistics when opposing Trap-Neuter-Return. Such high-profile sources have a responsibility to properly examine their sources and provide Americans with scientifically-supported information.

Worse, the data is circulated by unknowing media. Both the New York Times and the Los Angeles Times have repeatedly cited statistics attributed to the Wisconsin Study in the past—but their reporters and editors have apparently failed to investigate the accuracy of these numbers.

Bad science robs communities of real solutions—and costs cats their lives. Trap-Neuter-Return is the only effective approach for managing feral cat colonies. Sound policy decisions about animals’ best interests cannot be made based on unsound science.

Real science shows that removing feral cats creates a “vacuum effect”: Cats from neighboring areas move into the newly available space to take advantage of food and shelter. These cats soon begin to breed to capacity. Before long, just as many cats can be found in the area as were there before.

Scientific research has observed the vacuum effect across many species. Removing cats from an area is a futile effort—one that cannot succeed. Municipalities engaged in any type of catch and kill efforts are fighting a cruel, endless, losing battle against nature that is a gross waste of taxpayer dollars.

One of the few documented efforts to remove a population of cats by catch and kill occurred on a uninhabited (sub-Antarctic) island: Marion Island. It took 19 years of ruthless methods—methods impossible to recreate in areas inhabited by people, such as introducing disease and poisoning—to clear the island of cats. Over those 19 years, scientists noticed that when cats were cleared from a “preferred” area of the island, cats from another area took their place. In other words, even as scientists worked to kill the cats, they observed the vacuum effect.

Trap-Neuter-Return avoids the vacuum effect. Trap-Neuter-Return stabilizes the population, which then decreases over time. It also improves the cats’ health by ending the stresses associated with mating and pregnancy.

Do Feral Cats Live Miserable Lives?

Research proves that feral cats do not suffer harsh lives, pose a risk to other cats, or threaten public health. Feral cats live full, healthy lives outdoors. Claims that feral cats “suffer” outdoors are based on isolated incidents and are not supported by scientific evidence. Research of feral cats in high-volume spay/neuter clinics spanning nearly a decade found the need to euthanize for debilitating conditions was less than 1%. Anecdotal reports by caregivers bolster these findings.

Feral cats are just as healthy as “pet” cats—studies show they have the same low rates of disease. Despite recent media reports, there hasn’t been a confirmed case of cat-to-human rabies transmission in more than 30 years, according to the Centers for Disease Control and Prevention (CDC). Rabies in cats is extremely rare; in 2010, less than 5% of all reported rabid animals cases were cats, according to statistics from the CDC. Rabies vaccination is part of Trap-Neuter-Return (TNR) protocol, making successful rabies prevention programs even more effective.

FIV and FeLV are also extremely rare in feral cats. Major scientific studies of hundreds of feral cats found rates of these diseases to be just as low as companion animal cats.

Science shows feral cat colonies pose no disease risk to humans. Rumors about the spread of infectious disease by cats to humans is based on myth and misunderstanding, not science. Infectious diseases from cats can spread to humans only via direct contact, and that’s extremely unlikely among feral cats, who avoid humans. In people, incidences of these diseases often have other causes. Toxoplasmosis, for example, is almost always caused by consuming undercooked foods.

Trap-Neuter-Return makes feral cats even healthier. Trap-Neuter-Return ends the breeding cycle, as well as the strains of mating and pregnancy, which improves the cats’ overall health. Studies of cats cared for through TNR show they have healthy body weights and fat distribution. One long-term study of a TNR program showed 83% of cats had lived in the colony for more than six years, indicating a healthy lifespan comparable to companion animal cats.

Feral Cats Are Not To Blame

While some wildlife groups may use media attention to speculate that cats are causing species loss, leading biologists, climate scientists, and environmental watchdogs all agree: endangered species’ fight for survival rests in our own hands.

Focusing on cats diverts attention from the far more dangerous impact of humans. Too many media stories sidestep these realities to focus on sensational issues like cats’ imagined impact on birds. But cats have been a natural part of the landscape for over 10,000 years—that has not changed. What has changed in that time is how we have re-shaped the environment to suit 21st century human needs—at a great cost to the other species that share our ecosystem. Our direct impact on our environment is without a doubt the number one cause of species loss.

Make no mistake—habitat loss is the most critical threat to birds. With this exponential human population growth comes massive use of natural resources and rampant development: industrial activity, logging, farming, suburbanization, mining, road building, and a host of other activities. The impact on species from habitat destruction, pollution, fragmentation, and modification is alarming. According to the World Watch Institute, “people have always modified natural landscapes in the course of finding food, obtaining shelter, and meeting other requirements of daily life. What makes present-day human alteration of habitat the number one problem for birds and other creatures is its unprecedented scale and intensity.”

Human activities are responsible for up to 1.2 billion bird deaths every year. Nearly 100 million birds die annually from collisions with windows; 80 million from collisions with automobiles; 70 million from exposure to pesticides. Millions of birds are intentionally killed by U.S. government-sponsored activities each year.

The human population continues to grow, threatening other species. Exponential population growth has left little land untouched by human development. In America alone, the population grew by 60 million people between 1990 and 2010, and experts predict we will add 23 million more people per decade in the next 30 years. That kind of growth—the equivalent of adding another California and another Texas to our already teeming population—is unprecedented in American history.

Killing cats will not save wildlife. Studies have shown cats to be mainly scavengers, not hunters, feeding mostly on garbage and scraps. When they do hunt, cats prefer rodents and other burrowing animals. Studies of samples from the diets of outdoor cats confirm that common mammals appear three times more often than birds. Additionally, scientists who study predation have shown in mathematical models that when cats, rats, and birds coexist, they find a balance. But when cats are removed, rat populations soar and wipe out the birds completely.

Some wildlife organizations and media outlets continue to quote scientific studies that have been proven inaccurate. A careful analysis of the science concludes there is no strong support for the viewpoint that cats are a serious threat to wildlife.

Although human civilization and domestic cats co-evolved side by side, the feral cat population was not created by humans. Cats have lived outdoors for a long time. In the thousands of years that cats have lived alongside people, indoor-only cats have only become common in the last 50 or 60 years—a negligible amount of time on an evolutionary scale. They are not new to the environment and they didn’t simply originate from lost pets or negligent animal guardians. Instead, they have a place in the natural landscape.

What You Can Do

Trap-neuter-return (TNR) is recommended only for colonies of feral cats who can be returned to supervised sites where long-term care can be assured. Stray, domestic cats need to be re-socialized and placed in homes. Spaying and neutering colonies of cats: stabilizes the population at manageable levels, eliminates "annoying" behaviors associated with mating (fighting, yowling, and "spraying toms"), helps make the animals easier to deal with over the long term (re: trapping for future veterinary treatment), is more effective and less costly than repeated attempts at eradication is humane to the animals and fosters compassion in the community.

The community, the caretakers and the property owner where the cats reside, should organize and carry out this plan. Money may be available from an established organization or may have to be raised by voluntary contributions. Local governments should be approached and asked to contribute to the fund, as TNR will save them money over time. The initial cost may seem high but the long-term costs are less than those spent on repeated eradication attempts. The major expenses are for equipment, veterinary services, and food.


Identify all those who feed the cats and all feeding sites. Make a list of all the cats, their state of health, and whether females are pregnant, or feeding kittens. Identify the cats who are only occasional visitors or who are friendly, as these may be companion animals. All neighbors should be notified of your procedures before trapping begins to prevent them from thinking you will harm the cats. The location should be evaluated as to whether or not it is an appropriate environment in which to keep the colony. Buildings scheduled for demolition or areas too close to major highways may not be suitable. For the most part, the area where the cats are living is the best place to keep them. If relocation is necessary, find a suitable new location. However, relocation should be the last option. The planning group may be very creative in finding a solution. Euthanasia is only recommended for very sick cats who cannot be treated.


Make arrangements for kittens and cats that may be tame enough to be domesticated after veterinary treatment. Rescuers and colony caretakers should sterilize all cats and kittens prior to adoption. They should charge an adoption fee which will help recover part of the cost. Early-age sterilization can be performed on kittens eight weeks old or two pounds in weight. Obtain humane traps and transfer cages, and learn how to properly use them. Make arrangements for transport, overnight stay, and delivery to and collection from the surgery.


Don’t leave the cat in an unprotected trap and never leave the cat where she might be threatened by other animals, people, or weather. Immediately cover the trap with a towel or blanket when the cat is caught in order to calm her down. When one cat has been trapped, it can be moved to the transfer cage so that the trap can be used for a second cat. Do not trap in inclement weather, especially during heat waves - traumatized cats are very susceptible to heat stroke. The use of "rabies poles" and tranquilizers are discouraged. Tranquilized cats may leave the area before the tranquilizer takes effect and can get into situations that could endanger their lives, such as wandering onto busy streets. Do not trap lactating mothers, if possible. If, however, a lactating mother is trapped you need to make a decision on whether to have her spayed - she could be hard to retrap. If you keep her, find her kittens as soon as possible.


Discuss the plan with the veterinarian and a possible fee reduction for the whole colony. Confirm beforehand that the veterinarian and technicians are aware that these cats are feral and prepared to treat them. A squeeze-side cage is an option for the clinic to use. A moveable panel in this type of cage immobilizes the cat allowing her to be tranquilized before handling. It is much safer for the veterinarian to tranquilize the cat through the bars of the trap. To avoid the necessity of a second trapping, dissolvable sutures must be used. Males should be fostered overnight and females, if possible, should be kept for two to three nights before returning. All cats to be returned must be identified by clipping one quarter inch off the top of the left ear. If the ear is properly cauterized, this procedure is trouble-free. All cats should be treated for worms and earmites, inoculated with a three-year rabies vaccine and distemper vaccine, and given a long-term antibiotic injection. Remember to inform the vet. that the cats are to be returned to their colonies.

Taming & Domestication: Although some older feral cats can be domesticated, the best time to tame ferals is before they are eight weeks old. While it is possible to domesticate some older kittens and cats, if no homes are available and your local shelter is killing unwanted domestic kittens, a more humane and practical solution is to sterilize feral kittens from 12 weeks old, vaccinate, and return to colony.


When returning to the original site is not possible, relocate the cat to a different site, such as a farm, a riding stable, or even a back yard, as long as new caretakers are willing to take responsibility for consistent food and shelter. Relocating may take several weeks or months and must be undertaken with the utmost of care. “Dumping” of feral cats in rural areas is strongly discouraged as the cats will, in all probability, move off and be unable to a food source. They may starve to death. If you do not confine the cats properly for 2 to 3 weeks, they may not remain on the property. This can lead to a similar situation as mentioned above.


The long-term management of the colony should include arrangements for daily feeding, fresh water, and provision of insulated shelters as sleeping places with waterproof covers and straw. Dust bedding with flea powder to prevent infestations, and keep feeding areas clean and tidy.  It may take several months to bring a large colony under control and achieve stable groups of contented and healthy cats. Any new cats attaching themselves permanently to the colony should be trapped and sterilized. Many of these may be tame, domestic strays. These should be resocialized and placed in homes. Feral cats can be re-trapped a few years later for booster rabies vaccinations, health check-ups, teeth cleaning etc. At this time, they will be more trusting of their caretaker and can be tricked into cages and traps. A plan should be worked out with the veterinarian where mild illnesses can be treated in the colony with antibiotics placed in moist food, to avoid re-trapping.

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