Outdoor Cats

Video: Surviving the Wild: Cats & Birds

Click here to view a video from the American Bird Conservancy that discusses the danger that outdoor domestic cats pose to native wildlife, especially birds.

April 2018 Meeting with Fairfax Officials

Members of ASNV met last April with representatives of the Fairfax County Animal Shelter Advisory Board to discuss concerns about the impact of free-roaming cats on birds and other wildlife and about the shelter’s Trap, Neuter, and Return program.  At the conclusion of the meeting, animal shelter officials invited ASNV to comment and offer suggestions on how the subject is covered on the shelter’s new website.

ASNV submitted comments urging the use on the website of more scientifically based information, including such statistics as:

  • Free-roaming, unowned, and “community cats” have contributed to or caused the extinction of 63 species of bird, mammal, and reptile worldwide.

  • In the United States each year, cats kill 2.4 billion birds and 12.3 billion other native animals such as chipmunks and squirrels.

  • In North America, cats are second only to habitat loss as the largest human-related cause of bird death.

The ASNV members added that in the best interests of cats, birds, and other wildlife, the animal shelter should add a section to the website titled, “Cats Safe Indoors,” to educate visitors about the many benefits of keeping cats indoors and the risks posed to birds, other wildlife, and cats themselves by allowing cats to roam free.  The group also wrote that the website would be strengthened by including local, state, and federal laws regarding the release of unwanted pets. 

You can see the entire response  here.

January 2018 Statement of Betsy Martin (Audubon at Home Coordinator, Fairfax County) on behalf of Audubon Society of Northern Virginia, to the Fairfax County Environmental Quality Advisory Council 

I want to bring to your attention a grave threat to birds, wildlife, and humans that is being officially promoted by Fairfax County.

The Fairfax County Animal Shelter is actively promoting Trap-Neuter-Return (TNR), working with volunteers to trap feral cats, spay or neuter them, vaccinate them against rabies and distemper and give them a basic checkup, then eartipping and releasing them back to the location they were originally trapped.  There they become “community cats,” where the colony may be fed by local residents, or they “may survive and thrive without direct human intervention,” according to the website.  Presumably unfed cats survive by eating birds and other wildlife.

Although this program may sound like a humane way to address a feral cat problem, it is not, and the Audubon Society of Northern Virginia opposes it for the following reasons. 

1.      Living outdoors is bad for cats. 

Indoor cats are healthier and live longer.  Feral cats are exposed to weather and cars and other dangers and diseases.  Even if they are fed, they do not receive regular veterinary care.  It’s worth quoting at some length the thoughtful stance taken by People for the Ethical Treatment of Animals (PETA):

“Sadly, our experience with trap, spay-and-neuter, and release programs and ‘managed’ feral cat colonies has led us to question whether or not these program are truly in the cats’ best interests.  We receive countless reports of incidents in which cats—‘managed’ or not—suffer and die horrible deaths because they must fend for themselves outdoors.  Having witnessed firsthand the gruesome things that can happen to feral cats, we cannot in good conscience advocate trapping and releasing as a humane way to deal with overpopulation….We believe that although altering feral cats prevents the suffering of future generations, it does little to improve the quality of life for the cats who are left outdoors and that allowing feral cats to continue their daily struggle for survival in a hostile environment is not usually a humane option…Nevertheless, PETA’s position has never been that all feral cats should be euthanized.  We believe that trap, vaccinate, spay/neuter, and release programs are acceptable when the cats are isolated from roads, people, and other animals who could harm them; regularly attended to by people who not only feed them but care for their medical needs; and situated in an area where they do not have access to wildlife and where the weather is temperate.”  (emphasis added)

2.      Outdoor cats are bad for human health.

The Centers for Disease Control (CDC) has warned that feral cat colonies harbor diseases, including those that can be transmitted to humans[1].  (Cat-specific and zoonotic diseases include bartonellosis, toxoplasmosis, plague, endo-and ectoparasites, feline immunodeficiency virus, feline leukemia virus, and rickettsial diseases.) 

Rabies is a particularly important such disease.  Only a few people die from rabies each year in the U.S., but tens of thousands receive a rabies shot (postexposure prophylaxis, or PEP) due to potential exposure.  The interaction between cats and raccoons and other wild animals is the source of rabies infection by which cats can infect people.  Although wild animals are much more likely to be rabid, cats pose a disproportionate risk for human exposure because humans, especially children, are more likely to approach them.  Thus, various studies show that a disproportionate number of rabies shots had to be given due to cats.

Rabies is an insignificant cause of death in this country due to the practice of mass vaccination of dogs and control of stray dogs, which after the 1940s virtually eliminated canine rabies as the primary threat of infection to humans.  (Countries that do not vaccinate and control stray dogs still have many human deaths from rabies.)  There is no consistent U.S. effort to apply the same preventive measures to cats.  The Fairfax County TNR program vaccinates feral cats against rabies, but does not recapture and revaccinate after their initial trapping.  The CDC authors state that, “Maintaining adequate rabies vaccination coverage in feral cat populations is impractical, if not impossible.”  Therefore “these populations must be reduced and eliminated to manage the public health risk of rabies transmission.”  (p.5)  They argue that “requirements for rabies vaccination, requirements or incentives to spay or neuter, and prohibitions against free-roaming should be applied to cats as they are generally applied to dogs; they reflect standards of ownership that are appropriate for all domestic companion animals.” (p. 7)

Cats play an important role in the spread of toxoplasmosis, a parasitic disease that the Centers for Disease Control considers to be a “leading cause of death attributed to foodborne illness in the United States.” It is a special risk to pregnant women, who may transmit the disease to their unborn children.  Cats become infected by eating infected rodents, birds, or other small animals, then pass the parasite in their feces in a microscopic oocyst form.  Kittens and cats can shed millions of oocysts in their feces for as long as 3 weeks after infection.  A Toxoplasma-infected cat that is shedding the parasite in its feces contaminates the litter box, and if allowed outside, contaminates the soil or water in the environment , where the parasite can be transmitted to other animals and to humans.

3.       Outdoor cats kill many birds and other wildlife. 

Cats are a leading cause of declines in bird populations, second only to habitat loss.  An estimated 2.4 billion birds are killed by cats annually in the United States[2] (the 95% confidence interval of that estimate ranges from a low of 1.3 billion to 4.0 billion birds killed).  Of the billions of birds killed each year, an estimated 69% are killed by unowned or feral cats.  Data from the Northern Virginia Bird Survey, conducted annually by the Audubon Society of Northern Virginia (ASNV) since 1995, show a steady decline in the abundance of birds in our region.  We are very alarmed that Fairfax County Animal Shelter is promoting and assisting in the maintenance of colonies of feral cats that can and will further decimate local bird populations. 

In addition to birds, small mammals, amphibians, and reptiles are killed in large numbers by cats.  Domestic cats have contributed to at least 63 vertebrate extinctions and pose a major threat to threatened vertebrates worldwide[3].  Cats are an invasive exotic species that did not evolve in Virginia and do not belong in the wild in Fairfax County.  Fairfax County should consider the effect of its Trap-Neuter-Return program on the whole ecosystem, not just on the cats.

4.       Trap-Neuter-Return does not reduce outdoor cat populations.

The proponents of Trap-Neuter-Return have as one goal stabilizing or reducing the size of the feral cat population.  Yet, peer-reviewed and published scientific studies show that TNR for the most part does not, and cannot, reduce feral cat populations despite claims to the contrary  on the County website (see e.g., “Trap, Neuter, Return Program Decreases Homeless Feral Cat Population” at https://www.fairfaxcounty.gov/police/news-releases/2012/011912trapneuterreturn.htm ).  For example, one study[4] statistically analyzed and modelled the impacts on feral cat populations of two county-wide TNR programs, in San Diego CA and Alachua County FL.  The study found minimal or no effect of TNR on feral cat populations, which continued to grow.  The fecundity of the non-neutered cats easily compensates for the neutered sub-population.  It concluded that 71% to 94% of the cats would have had to be neutered to stabilize or bring about a decline in population.  This is far greater than the neutering rate that was achieved, or that could be achieved for an area as large as a county, with many separate cat populations.  The authors recommend that to be effective, Trap-Neuter-Return programs should focus on well-defined, preferably geographically restricted, cat populations, rather than diluting effort across populations in an area as big as a county.  Even the TNR programs focused on small colonies (“small” was 7 cats on average) that were found to be modestly successful only reduced population size very gradually.  In the meantime, bird predation continued for years. 

The food set out for a cat colony in the Fairfax TNR program is likely to attract additional cats, and may encourage abandonment of unwanted cats by people who think someone else will take care of them.   (It also may attract wild animals, which may transmit diseases to cats, or catch diseases from them.)

Park managers in Northern Virginia report that local parks are favorite “dumping grounds” for unwanted cats.  The American Association of Wildlife Veterinarians supports actions to ban or eliminate feral cat colonies in a humane manner on public lands managed for natural resource and discourages feral cat colonies on private lands (resolution passed in 1996).

Audubon Society of Northern Virginia asks that:

1.      Fairfax County should establish a policy of reducing outdoor cat populations.

2.      Fairfax County should pass laws prohibiting free-roaming cats (perhaps by expanding ordinances 41.1-2-2, which requires licensing of dogs, and 41.1-2-4, which prohibits unrestricted dogs, to also cover cats). 

3.      Any Trap-Neuter-Return program in Fairfax County (including the current one) should be subject to an independent evaluation and monitoring component that tracks information about numbers of colonies and cats, and that permits estimating the impact of TNR on the size of the feral cat population.

4.      Fairfax County should replace the Trap-Neuter-Return program with a program that humanely removes feral cat populations from the wild.  The program should be designed to protect the ecosystem and the lives of birds and wild animals.  The design of the program should be based on scientific evidence, and it should be subject to public review and comment before being implemented.   

5.      Feral cat colonies should be removed now from parks and other natural areas inhabited by wildlife. 

Fairfax County should revise the material posted on the Fairfax County Animal Shelter website and remove references to "community cats" and links to any outside organizations that promote releasing unowned cats to the environment.


[1] A.D.Roebling, D. Johnson, J.D. Blanton, M. Levin, D. Slate, G. Fenwick, and C. E. Rupprecht.  2014.  “Rabies prevention and management of cats in the context of trap, neuter, vaccinate, release programs” Zoonoses Public Health 61(4): 290-296.

[2] S. Loss, T. Will, and P. P. Marra.  2015.  “Direct mortality of birds from anthropogenic causes.”  Annual Review of Ecology, Evolution, and Systematics 46:99-120.

[3] S. Loss and P. P. Marra.  2017.  “Population impacts of free-ranging domestic cats on mainland vertebrates.”  Frontiers in Ecology and the Environment 15(9): 502-509.

[4] P. Foley, J. Foley, J. Levy, and T. Paik.  2005.  “Analysis of the impact of trap-neuter-return programs on populations of feral cats,” Journal of the American Veterinary Medical Association 227(11):1775-1781.