The Scourge of Feral Cats

Feral cats annually kill between 1.3 billion and 4 billion birds, according to a Smithsonian study. But Americans insist on sustaining feral cats in the wild.

Photo courtesy of American Bird Conservancy

By Ted Williams

Dusk descends over Honolulu, and from the shadows of bushes and buildings alien predators “come on little cat feet.” But unlike the fog that also hangs over this city, they do not move on. Instead, they wait to be fed.

The University of Hawaii is overrun by feral house cats. The whole campus smells like a litter box. The feral cats are fed by professors and students who also trap and medicate them, get them spayed and castrated, then release them. The idea is that the colony will eventually die out without individuals being subjected to the perceived hideous fate of euthanasia. The colony does not die out. The feral cats look sick and sad. Some limp. Others are missing ears, eyes, tails or fur.

The feral cats I encounter at feeding stations at Kapiolani Community College and Ala Moana Park, also in Honolulu, look no better. Dining with them at the college is a mongoose, another alien scourge, inadvertently sustained by feral cat feeders.

********

I made the above observations in 2009. Today both institutions discourage TNR for fear of running afoul of state and federal laws. But feral cats are still fed at Ala Moana Park.

In 2023 two women were cited by state wildlife officers for prohibited take via feral cats of an endangered species (the nene goose, Hawaii’s state bird) because they put out cat food in defiance of the officers’ orders. The women were part of a feral-cat advocacy group protesting the Queens’ Marketplace Shopping Center decision to remove feral-cat feeding stations.

Sustaining feral-cat populations in the wild, pioneered in North America at the University of Washington in the 1980s, is called Trap, Neuter, and Release (TNR). It’s all the rage across the United States. It doesn’t work. Its prolific critics call it “Trap, Neuter, and Re-abandon.”

Hawaii Administrative Rules outlaw “feeding colonies, strays, wildlife, or feral animals on any property under the jurisdiction of the state” -- 1,560,000 acres. But there are 2,440,000 acres not under state jurisdiction.

The Humane Society of Hawaii runs its “Feline Fix Program” that provides no-cost spay/neuter surgeries for feral cats on Oahu, a program supported by the City and County of Honolulu. The Society sterilizes close to 2,000 feral cats per year. That sounds impressive until you consider that 71 to 94 percent of any colony needs to be sterilized before there can be a decline (provided there’s no immigration) and that there are thought to be at least 100,000 feral cats on the island. What’s more, it’s nearly as hard to trap cats as it is to herd them, and welfare programs for feral cats encourage dumping of unwanted pets. TNR colonies generally grow.

Thousands of groups across the U.S. conduct TNR. According to the largest TNR practitioner, Alley Cat Allies based in Bethesda, Maryland, at least 200 of these (including Alley Cat Allies) are registered as tax-exempt 501-C3 “charitable organizations.” Funding from private donations, the pet industry, and municipalities is lavish. In 2023 (the most recent year for which data are available) assets for Alley Cat Allies amounted to $22,203,018.

“TNR advocates are very well organized and funded,” declares Steve Holmer, the American Bird Conservancy’s Vice President of Policy. “They’re getting ordinances passed all over the place.”

Wildlife biologists and law-enforcement officials contend that feeding feral cats violates federal law because it facilitates “take” of species protected by the Migratory Bird Treaty Act and/or the Endangered Species Act. But enforcement like that at Queens’ Marketplace Shopping Center is scant, and the take is prodigious. Holmer’s outfit estimates that 150 million free-ranging cats in the United States kill 500 million birds a year .

When the City of Los Angeles proclaimed on its Animal Services website that the National Audubon Society supports TNR the Society got the post removed by citing its board resolution opposing TNR. It reads in part: “Feral cat colony programs, wherein feral cats are captured, trapped, vaccinated, neutered, and fed, do not eliminate predation on native wildlife or reduce the size of feral cat colonies; and . . . bites, scratches, and fecal contamination from feral and free-ranging pet cats pose a risk to the general public through transmission of diseases such as toxoplasmosis, roundworm, and rabies.”

The one thing feral cat advocates and native wildlife advocates agree on is that pet cats should be kept indoors. But, even if cat owners complied (and most don’t), that’s no solution. Cats have been reproducing in the wild since European contact. Recalling his 1866 visit to Hawaii, Mark Twain wrote: “I saw cats -- Tom cats, Mary Ann cats, long-tailed cats, bobtail cats, blind cats, one-eyed cats, walleyed cats, cross-eyed cats . . . platoons of cats, companies of cats, regiments of cats, armies of cats, multitudes of cats.”

********

The multitudes of feral cats that blight America hasten the extinction process. On Hawaii’s big island alone there are an estimated one million feral cats. They depredate nests of the palila, an endangered honeycreeper. Ten thousand feet up on Mauna Loa, feral cats are snatching endangered Hawaiian petrels from their burrows. The single chick can’t fly for 15 weeks, and adults don’t breed until they’re at least five years old. On Kauai, threatened Newell’s shearwaters get disoriented by lights and crash. Usually, they’re unhurt, but because they can’t take off from land people pick them up and deposit them in large “mailboxes” at fire stations from which they’re collected and returned to the sea. But feral cats have learned to congregate under the lights, and they kill the birds before they’re rescued.

On Maui two feral cats killed 143 wedge-tailed shearwaters in one night. Wedge-tailed shearwaters lay one egg a year only after they’re seven years old; and if one parent is killed, the chick dies. Researchers found Hawaiian stilt parts in 12 percent of the feral cat stomachs they checked. The Maui Coastal Land Trust points out that seabird guano that used to enrich coastal wetlands throughout the state has declined to the point that alien plants are destroying these habitats.

When Dr. Fern Duvall served as a biologist with the Hawaii Division of Forestry and Wildlife he compared seabird production on feral-cat-infested main islands and offshore islands where feral cats were absent. He found 13 percent nesting success on the former, 83 percent on the latter.

The fact that there are fewer birds in urban areas doesn’t mean TNR is okay in cities like Honolulu, notes Duvall. “We finally have the amakihi, one of our native honeycreepers, somehow adjusting to avian malaria,” he says. “This is the thing everyone’s been waiting for, a forest bird adjusting to introduced disease. They’re recolonizing former habitat in Honolulu only to be taken out by feral cats.”

Although feral cats elsewhere in the nation must contend with wolves, coyotes, foxes, fishers, badgers and bobcats, they frequently outnumber all these native predators combined and compete with them and raptors for prey. This is the case in Wisconsin, where the U.S. Department of Agriculture and the state Department of Natural Resources fretted that in creating new habitat for declining grassland birds they were funneling them into cat gullets. Accordingly, they commissioned Dr. Stanley Temple, professor of ecology at the University of Wisconsin Madison, to undertake a major field study of house cats.

Temple surveyed 1,200 landowners in rural Wisconsin, learning that most pet cats are allowed to hunt outdoors. His data indicate there are at least 1.4 million feral cats and free-ranging pet cats in rural Wisconsin. From observing cats he’d radio-collared and examining scats and stomach contents (the latter obtained with a mild emetic), he got an estimate of between five and six birds killed per cat per year. That means that cats are annually knocking off around 8 million birds just in rural Wisconsin.

Twenty years ago the Wisconsin Conservation Congress -- a purely advisory entity sired by Aldo Leopold to encourage public participation in Department of Natural Resources decision making -- considered a proposal to recommend that free-ranging cats be placed on the unprotected list along with skunks, starlings and the like. At hearings in 72 counties the proposal was supported by a majority of the public. It was hardly a radical notion because feral cats have long been classified as unprotected wildlife in other states. It wasn’t even necessary because there had never been a Wisconsin law against killing problem cats on one’s own property.

Still, cat lovers caterwauled. Failing to grasp the difference between game protected by seasons and bag limits and unprotected nongame, the press wrongly reported that the state was considering opening a hunting season on house cats. One inflammatory piece, in the Wisconsin State Journal, was used in a Society of Environmental Journalists workshop as an example of how to warp news. The din ultimately induced Governor Jim Doyle to issue a proclamation that cats wouldn’t be hunted in Wisconsin.

In all his research Temple has never killed a cat, never advocated cat removal, never taken a position on placing cats on the unprotected list. But because his data were cited by native wildlife advocates, feral cat lovers confronted him with hysterical shrieking sufficiently sustained to preclude response. Others have vowed to kill him. One woman, recorded on his answering machine, hissed: “You cat-murdering bastard. What goes around comes around. I declare Stanley Temple season open.”

Such is the mindset of feral cat lovers across the country. “It’s like a religion,” remarks Duvall, who also has received death threats. “You can’t sit down and reason with most of these people.” Facts are dismissed, data denied, suffering of wildlife and cats ignored. For example, the official policy of the No Kill Advocacy Center of Oakland, California, is that feral cats must be protected as “healthy wildlife.” The Santa Monica-based Voice for the Animals Foundation even stocks feral cats for supposed “rodent control.”

When Norma Bustos served as Hawaii’s Seabird, Shorebird, Waterbird Coordinator she gave a presentation on the ecological dangers of feral cats. She projected photos of cat feces full of bird bands, Hawaiian petrels decapitated by cats, cat-mangled wedge-tailed shearwaters, and a video of a cat dragging a palila chick from its nest. Attendees screamed at her and trotted out the fiction that if people feed feral cats, their stomachs will be full and they won’t kill birds. When Bustos suggested that pet cats should be kept indoors, a feral cat lover shouted: “If you’re so worried about the birds, you should keep them indoors!”

Elizabeth Parowski, communications manager for Alley Cat Allies, informs me that the American Bird Conservancy’s estimate of 500 million birds annually killed by feral and pet cats (conservative because some estimates place the figure at a billion) is “conjecture and the Conservancy admits that.” That’s an untruth. When I ran her statement by the Conservancy’s Holmer, he explained that the estimate is based on excellent data from the pet industry and extrapolations by respected researchers like Temple.

Dismissing Temple’s statistics, Parowski says: “I know about his work. It’s never been peer-reviewed, never been published.” That is also an untruth. Temple’s work has been subjected to extensive peer review and has been published many times, originally in the Wildlife Society Bulletin.

“Feral cats are territorial,” Parowski asserts. “They will keep other cats from moving into their territories. That’s why trap and kill is so ineffective -- because of the vacuum effect.” Without exception, I get the same line from every TNR flack I talk to. It’s rubbish. “The very fact that you can create a feral cat colony tells you they’re not territorial,” says Temple.

********

At least 73 percent of feral cats in Hawaii are infected with toxoplasmosis, a parasite that sheds oocysts into the bowel. Cats are the only vector. Copious oocyst-laden cat feces is killing red-footed boobies and endangered nene geese. When the disease started killing endangered Hawaiian crows, all birds had to be evacuated from the wild and maintained in captivity. The species was declared “extinct in the wild,” but in November 2024 five captives were released. Endangered monk seals die from toxoplasmosis. It’s nearly as epidemic in other states. Cats have passed toxoplasmosis to California sea lions, harbor seals and sea otters. One study found toxoplasmosis in 42 percent of live sea otters and 62 percent of dead ones.

In humans, toxoplasmosis damages embryos, causing infant mortality, cerebral palsy, blindness, mental retardation, and other birth defects. Feral cats also transfer roundworms, hookworms, and ringworm (a fungus infection) to humans and wildlife. In Florida 75 percent of feral cats studied had hookworms; and 93 percent had fleas, which pass such diseases as Bartonella, Ricksettia and Coxiella between animals and humans.

Feral cats spread the feline leukemia virus to cougars, bobcats, threatened Canada lynx and endangered Florida panthers.

In 1992 the Humane Society of the United States published this directive: “Responsibility means rescuing the cats and either taming them and placing them in homes, or humanely ending their lives, but nothing short of either.” But it has flip-flopped, presumably because of TNR’s soaring popularity. In 2025 “HSUS advocates community-based TNR programs with on-going responsible management as the most viable, long-term approach available at this time to reduce feral cat populations.”

In rural areas where feral cats are killing migratory birds and threatened or endangered wildlife, the only way for state or federal management agencies to attempt control (and therefore the way mandated by federal law) is for pest-exterminator professionals retained by state or federal resource agencies to shoot them in the head with rifles, a form of euthanasia approved as humane by the American Veterinary Medical Association.

Australia successfully controls feral cats with fast-acting, selective poison deployed in boxes accessible only by cats. But unlike Australia, the U.S. declines to register feral-cat poisons. Cats quickly learn to avoid traps and gun-toting managers. So U.S. control is largely ineffective.

********

Because Audubon Magazine had assigned me to write a column about feral cats (from which the above copy is adapted and updated) the National Audubon Society asked me to hatch an op-ed for the Orlando Sentinel about a Florida bill that would implement TNR. I was told that the Florida Audubon chapter “didn’t have time to write an op-ed.” I didn’t have time either, but I wanted to help. So I undertook the project for no pay.

In the op-ed I accurately reported that selective feral cat poisons like Tylenol were not registered for use by wildlife professionals because of opposition from feral cat supporters. Alley Cat Allies, Vox Felina and National Audubon Society president David Yarnold (assuming The New York Times accurately reported his statements) claimed that I had recommended that “individuals” poison cats in “backyards.” I had done no such thing.

In less than a day the National Audubon Society received 33,000 form-letter emails generated by Alley Cat Allies demanding my dismissal: “Send this petition to Audubon telling them to fire cat-murderer Ted Williams; and click here to donate $5 -- or more -- to Alley Cat Allies.” They crashed Yarnold’s computer. So many feral-cat advocates marched down Broadway in protest that Audubon employees couldn’t get into the building.

I got fired, despite the fact that in every issue for 33 years I had written a feature-length, award-winning conservation column first called “Ecopinion,” then “Incite” and (for most of those years) an award-winning natural-history column first called “Earth Calendar,” then “Earth Almanac,” despite the fact that I had worked for Audubon magazine longer than any staff member, despite the fact that the National Audubon Society had assigned me to write the op-ed, and despite the fact that the op-ed contained no factual errors and no “suggestions.”

After I was dismissed, condemnation of the National Audubon Society by the environmental and mainstream media and by letters and op-eds from birders and bird groups went far more viral than the Alley Cat Allies nastygrams. Audubon promptly hired me back. The feral-cat fiasco story even made it to The New York Times which, because it interviewed Yarnold and not me and apparently because it had not read my op-ed, got the story wrong. I made the following corrections in a letter to the editor:

“I need to correct an unintentional implication by the Times and the National Audubon Society, which reads: “‘We absolutely reject the notion of individuals poisoning cats,’”Audubon CEO David Yarnold said.” And: “The society also said that while cats were still a leading cause of bird deaths, it did not endorse Mr. Williams’s suggestions.” “‘Backyard poisoning isn’t the answer and we want to make it absolutely clear we don’t support that idea,’ it said.”

Among my lapses of judgment in the Orlando Sentinel op-ed, suggesting “backyard poisoning” by “individuals” was not one. Lethal control of feral cats would be (and is) conducted strictly by wildlife professionals and not in backyards.”

Ironically, all the flap accomplished what the National Audubon Society wanted; the bill died.

Shortly thereafter, new editors took over Audubon, requiring that all articles be about birds. I wanted to write about birds but not just birds. I also wanted to keep writing about mammals, fish, reptiles, amphibians, insects and plants. So I decided to quit my Incite column. And Audubon’s rapidly shrinking pages left no room for my “Earth Almanac” column. I did leave the door open for the occasional feature and website piece, several of which I’ve done.

I never criticized the National Audubon Society, nor have I done so in this piece. Reporting facts is not criticism. I wish the National Audubon Society nothing but success. After I quit writing my Audubon columns, I continued to raise major funds for the Society via two charitable foundations I served on.

- 30 -

Ted Williams, a former information officer for the Massachusetts Division of Fisheries and Wildlife, writes rare books as well as articles for low-paying publications. For his Audubon work he was named to the Circle of Chiefs of the Outdoor Writers Association of America (the group’s highest conservation award); nominated by the American Society of Magazine Editors for the National Magazine Award, received the C.F. Orvis Writing Award, the Nautilus Book Award (for a collection of his “Earth Almanac” essays), the “Conservationist of the Year Award from the Coastal Conservation Association, the “Award of Merit” from the Federal Wildlife Officers Association, and 15 “Excellence in Communications Awards” from the Outdoor Writers Association of America for his “Incite” columns.