[This story appears as an on-going series in the "Gilroy Dispatch"]
Feral Cats are Killing our Native Birds January, 2013 By Amy Yee
Full disclosure: I love cats. My family had pet cats for much of my childhood. However, there are far too many feral cats-cats that were once domesticated but have returned to the wild, or ones born in the wild-out there.
These cats often live in colonies near restaurant parking lots, in open fields, or close to urban biking and hiking trails. Many kind-hearted people provide food and water for feral cats at feeding stations. Some caregivers also trap these cats and have them neutered at their own expense, sometimes by generous veterinarians who perform the procedures at reduced cost. When they have recovered from their surgeries, the cats are released back to their feral colonies.
Adult feral cats can almost never be tamed. They will always be wild and cannot be socialized to humans.
Where do these cats come from? Sadly, many are former pets abandoned by their owners and returned to their instinctual wild ways. Others are the offspring of these abandoned pets, born and raised in the wild. One female cat can produce up to 100 kittens in her lifetime.
Why are feral cats a problem? Simply stated, feral cats kill native wildlife. The National Wildlife Federation estimated in 2011 that there are 117 to 157 million feral cats in the United States.
Cats are, by nature, hunters. Even the most well-cared-for, well-fed domestic cat will stalk and kill birds and other creatures when it goes outdoors. The long-range environmental problem, however, is not the occasional bird your cat brings you as a gift. According to the American Bird Conservancy, the Audubon Society, the Cornell Lab of Ornithology, the Smithsonian Institution, and the U.S. Fish and Wildlife Service, the magnitude of avian destruction is in the millions, if not billions of birds each year.
A study reported in the scientific journal Nature in January 2013 put it succinctly: "We estimate that free-ranging domestic cats kill 1.43.7 billion [emphasis added] birds and 6.920.7 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic [caused by humans] mortality for US birds and mammals. Scientifically sound conservation and policy intervention is needed to reduce this impact."
A small study conducted by the Smithsonian Institution tracked young gray catbirds in the Washington, D.C., area. Of 69 chicks tracked, 42 died their first year. Of those 42, 40 percent were killed by feral cats. This means that 25 percent, or one-fourth, of the chicks that hatched were killed by feral cats.
Some people have tried to reduce the size of feral cat colonies using the TNR procedure described above: trap, neuter and release. If the feral cats are all neutered, they won't reproduce and the cats will eventually disappear, right? Unfortunately, that's not the way research has shown it to work. Studies have concluded that at least 70 percent of the cats in a colony must be sterilized for TNR to affect the population level. New cats are always arriving; in fact, the existence of a colony may encourage the dumping of unwanted cats.
The life of a feral cat is short and sad. The American Veterinary Medical Association estimates that free-ranging cats have less than half the life expectancy of indoor cats. The causes of these deaths can be gruesome-getting hit by cars, being mauled by dogs or becoming a meal for foxes and coyotes. Life outdoors also means greater exposure to diseases such as toxoplasmosis, feline leukemia, and rabies. (These are good reasons to keep your pet cat indoors, too.)
. A 2013 article in the journal Zoonoses and Public Health reported that "As a rabies vector, cats pose a disproportionate risk for potential human exposures compared to other [wildlife] in part because people, and especially children, are more likely to approach them."
Feral cat colonies are breeding grounds for disputes among species that would not normally cross paths, and for transmission of diseases. A recent Urban Wildlife Research Project study set up night-time cameras at feeding stations. Seventy-four percent of the animals eating the cat food were skunks. Fifteen percent were raccoons, 7 percent were gray foxes, and-get this-only 4 percent were the feral cats for whom the food was intended. Wild birds were also observed eating the cat kibble and feeding it to their chicks. Cat kibble is not a natural food for any wild animal.
What is the solution? For starters, better education about the negative effects of feral cats on the environment, the ineffectiveness of TNR, and the benefits of responsible pet ownership might reduce the numbers of feral cats out there. Tougher regulations and enforcement of existing regulations mandating neutering and prohibiting the dumping of unwanted cats would help, too.
This is an issue about which many people are passionate, but I hope not polarized. We need to come together to try to find some common ground that is good for us, for the cats, and for our native wildlife.
WERC is a licensed 501(c)(3) organization that has been providing wildlife education and rehabilitation services in the South County for 23 years.
Amy Randall Yee has lived in Santa Clara County for 35 years and has volunteered at WERC for six years. She is the President of the Board of Directors of WERC. Contact her at firstname.lastname@example.org.
W.E.R.C., the Wildlife Education and Rehabilitation Center provides the community with rehabilitation services for orphaned, injured and sick native wildlife. Through our educational programs, W.E.R.C. encourages a peaceful coexistence between civilization and our native wildlife. Federal tax ID #77-0324296