Fine Furry Friends
by Dr. Sarah D. Oktay
Managing Director UMass Boston Nantucket Field Station
Most people don't realize that a cold blooded killer lives in relative security in their homes, quietly biding its time and twitching in anticipation of its next victim. In fact, I have two of them in my house, both furry and cute and like most of their cousins on-island, gray striped tabbies. Few issues can raise such a mixed bag of emotions like the control and management of feral cat populations and the exotic and/or invasive niche that formerly domesticated cats are currently occupying in our environment. In fact, on Nantucket, feral cats are likely the most signficant non-avian "apex" predator, serving a role normally played by larger predators on the mainland.
Both feral and domestic cats are scientifically known as Felis catus, a Wile E. Coyote Latin name if ever there was one; and they originated from an ancestral wild species, the European and African wild cat (Felis silvestris). Felis catus is now considered a separate species. The estimated numbers of pet cats in urban and rural regions of the United States have grown from 30 million in 1970 to 65 million in 2000 to estimates of over 100 million today. Nationwide, approximately 30% of households have cats. In rural areas, approximately 60% of households have cats. What is the difference between a feral cat and a free roaming cat? A feral cat is a domesticated cat that has returned to the wild or been born in the wild; they are a bit different than stray cats, which are lost or abandoned cats. The offspring of abandoned pets become feral cats. According to the MSPCA ( Massachusetts Society for the Prevention of Cruelty to Animals): "A free-roaming cat is a tame cat who is friendly toward people, and can either be a cat that has an owner but is allowed to roam outside, or a cat that was formerly owned, but has been abandoned or lost. A feral cat, however, is the wild-born offspring of free-roaming or other feral cats."
Not so long ago, almost all cat owners let their cats outdoors, especially at night, and they were prized as "mousers' by rural families. Today, it is extremely difficult to find statistics on the number of cat-owners who let their cats outdoors, but a reasonable estimate is 30-50%. Whether free-roaming or feral, a cat outdoors will become a predator and will impact its local environment. In addition, its lifespan will be reduced due to the increased number of mortaility and disease factors associated with living outdoors. They are more likely to be hit by cars, attacked by dogs, intentionally stolen or poisoned, and they can be exposed to fleas and ticks and can bring these back into the home. We don't have to worry about them on Nantucket, but coyotes are a frequent predator of cats. Free-roaming cats are more likely to have contact with other cats that carry feline diseases including Feline Immunodeficiency Virus (FIV) and Feline Leukemia (FeLV) which can be transmitted from an infected cat. According to the MSPCA, the average lifespan of cats permitted to roam freely outside is estimated to be only 2 to 5 years, whereas indoor-only cats can live to be 18 years or more. In addition, cats that are permitted to roam outdoors unsupervised can have a negative effect on local wildlife populations; as natural predators, even the common housecat can do an incredibly effective job killing birds, rodents, and reptiles. This can cause serious environmental problems, especially if there are endangered or federally protected species present.
As to the mental health of cats allowed to roam outdoors, the prevailing wisdom is that they will be less prone to boredom and will have healthier body weights, but responsible cat owners can provide ways to exercise cats indoors. The ideal solution is to have an enclosure or outdoor space in which cats can roam about inside a fence or patio and enjoy the outdoors, but be restricted in their interactions with birds, cars, and other cats.
Many humane societies, animal shelters and animal advocacy groups reccommend that communities adopt Trap Neuter and Release/Return (TNR) programs as a way to reduce the feral cat population. On Nantucket we have a dedicated group of volunteers who help trap feral cats and take them to the MSPCA to be evaluated, neutered, and then released. Some people provide feeding stations to allow feral cats to thrive outside, which may reduce their hunting forays. These folks raise money and use their own funds to pay for these efforts.
There is an inherent controversy about these programs that has been brewing for many years. Advocacy groups for wildlife, biodiversity, conservation, and especially those for birds believe that these programs do not go far enough and that removal of feral cats from the environment and education of pet owners to convince them to keep their pets indoors is critical. A very vocal advocate of keeping cats inside is the American Bird Conservancy. The National Wildlife Federation's recent stance comes down firmly on the side of reducing the number of feral cats http://blog.nwf.org/wildlifepromise/2011/03/new-studies-highlight-impact-of-outdoor-cats-on-birds-and-other-wildlife/ This articles echoes the position of the Wildlife Society who first advocated for euthanization over TNR back in 2003 and then released two months ago a series of articles entitled "In Focus: The Impacts of Free-Roaming Cats" which is an even stronger statement on the need to agressively control feral cat populations. These organzations contend that feral and free-roaming outdoor cats kill 1 million birds a day (some researchers claim 1 billion per year world wide) and that somewhere between 117 million and 157 million feral and free-roaming cats can be found in the United States. The Wildlife Society asserts that the Felis catus is the most abundant carnivore in North America. Domestic cats are now listed in the top 100 worse invasive creatures world-wide.
There are respected organizations on both sides of this issue. The Humane Society advocates TNR not euthanizing. Their official TNR policy states "The HSUS advocates community-based Trap-Neuter-Return programs with on-going responsible management as the most viable, long-term approach available at this time to reduce feral cat populations. Responsible management of existing feral cat colonies should include: humane trapping, sterilization, removal of kittens and friendly adult cats for possible placement in homes,rabies vaccination, treatment for illness or injury, and euthanasia of animals whose suffering cannot be alleviated. Ear-tipping and returning ferals to the same location where they were trapped (provided they would not face imminent risks) is another option. And so is providing lifelong care consisting of adequate food, water, and shelter as well as regular monitoring of the colony for sickness, injury, and the arrival of new animals. The goal of any feral cat management program should be to maximize quality of life for the cats and to eliminate the existing colony over time through attrition.” They go on to specify that “The HSUS values the lives of individual wild animals, no matter their species status. The goal of any TNR program should be to lessen the impact on wildlife by reducing the number of feral cats and eventually eliminating their presence from the environment.”
There is also research that shows that feral cats in TNR programs can live relatively long lives, carry less diseases than is sometimes reported, and that in time their numbers can be controlled and reduced. In 2003, a long-term study of a Trap-Neuter-Return program noted that 83% of the cats present at the end of the observation period had been there for more than six years. As for FIV, a 2008 report found almost equally low rates of FIV and feline leukemia (FeLV) in feral cats (4.3%) and outdoor pet cats (5.8%). A study of seven Trap-Neuter-Return programs from 2006 produced similar data: only 5.3% of the cats tested positive for one of those diseases. It is important to remember that a cat kept indoors will have a very slim chance of contracting these diseases. And of course, in the relative safety of your home, they cannot impact lizard, mice, or bird populations outside your home.
So the status of the animals, their role in the ecology and habitat and their natural and acquired prey and predators all become factors in control measures. Research by David I. King of the U.S. Forest Service's Northeastern Research Station and John H. Rappole of the Smithsonian Conservation and Research Center found that the biggest problem for bird populations is the loss of the birds' winter habitat in the tropics due to deforestation. Feral cat TNR advocates point to these reports as evidence that feral cats are not to be blamed, but the reality is that a preponderance of multiple factors (like in almost all environmental issues) is causing a depletion in bird populations.
There is also competing evidence on the efficency of TNR programs. It has been concluded that a comprehensive long-term program of neutering followed by adoption or return to the resident colony can result in reduction of free-roaming cat populations in urban areas.
Other researchers argue that TNR programs are ineffective in reducing feral cat populations and that organizations and scientists who advocate TNR tactics are ignoring on-the-ground realties of excess feral cats in the environment. They state that feral cats do not fill a niche in the environment because they often exist at concentrations that are 10-100 times greater than native wild populations.
Sadly, this issue is an extremely important one for Nantucket. We have a much larger free-roaming cat population than other areas with simular human populations due to the seasonal nature of the majority of our residents and the lack of predators who could limit the population. If an outdoor cat cannot be found when it is time to get back on the ferry to go home, some owners feel they have little recourse than to give up looking and hope the cat can fend for itself. Compounding this common occurrence is the fact that there are few real predators for domestic cats other than dogs and larger raptors. Disease and cars and starvation can account for some control of the population; but at least anecdotally, the feral cats I have seen seem to be relatively healthy looking (good weight, mobility, and coat appearance) and no slouches when it comes to hunting. I do think their contributions regarding reducing our mice and rat population may be underrated, and I would be interested in seeing a joint population study of both small mammals and cats in a controlled study area. But it is easy to see that our least terns and plovers and other ground nesting birds are literally sitting ducks. These protected ground nesting birds have a chance on our island because we don't have coyotes and foxes and other larger mammalian predators, if not for the crows, rats, and cats, they might do even better.
When municialities attempt to reduce feral cat populations they often find there are more cat lovers out there than they thought. Town administrators in Monahessen Pennsylvania drew angry protests from cat "owners" who found out their outdoor cats had been rounded up and taken to a shelter to be euthanized. The take-home message here is to keep your pet indoors. Our household adopted a feral cat when we moved here seven-and-a-half years ago and then aquired another one three years ago. We have never allowed our cats outside for two reasons: I was worried that they would go capture the first piping plover they could find or that they woud end up as an tasty (although feisty) meal for our neighborhood red tailed hawk. Neither option was appealing and, since I was raised in a house full of indoor cats who tolerated the few humans present, I knew that a cat could be relatively happy indoors and certainly healthy.
Free-roaming cats obviously can also pose a serious risk to birds and wildlife. It can be argued that they fill a niche in maintaining the population of mice rats and other small mammals. The difficulty lies in where the rights of one animal end and another begin and what the "natural" viable or healthy population should be. Feral cats' role in the variety of vectors (host of various life stages of ticks, relationship to rabbit population) related to tick-borne disease may also be a factor on Nantucket. I would certainly advocate at a minimium maintaining or enhancing our TNR program (with some quantitative data on the efficacy of the program) and keeping cats indoors in addition to education efforts to inform people of the damage a cat can do outside. Now I have to go feed my cats, before they figure out how to open the front door. At least I can feel good that they are not reducing anything except my bank account.
