Cats Are Fueling a Global Eco-Crisis, Pushing Birds and Other Species to Extinction

By Reynard Loki

Last of two parts

Conservation Strategies and Solutions

Addressing the problems caused by outdoor cats requires a multifaceted approach that respects animal welfare while prioritizing ecological integrity.

Keeping Pet Cats Indoors

This is the simplest and most effective solution—and one we’re lucky to have today thanks to the invention of kitty litter, as Alley Cat Allies points out. Indoor cats live longer, healthier lives (avoiding predators of their own and car traffic) and pose no threat to birds. Cat parents can provide enrichment through toys, scratching posts, window perches, and “bird TV” to satisfy their pets’ instincts without exposing them to outdoor dangers.

“Catios”

For guardians who want their cats to enjoy the outdoors safely, enclosed outdoor spaces (“cat patios” or “catios”) are an excellent option. “A catio is an outdoor enclosure that keeps cats and birds and wildlife safe,” writes Cats Safe at Home, a collaboration between the Feral Cat Coalition of Oregon, Bird Alliance of Oregon, Bird Conservation Oregon, and Multnomah and Washington County Animal Services dedicated to protecting both cats and wildlife. “Catios offer cats healthy exercise time as well as safety from outdoor hazards like cars, predators and poisons, while preventing predation on birds. A catio is a win-win solution.” Karen Kraus of the Feral Cat Coalition of Oregon said, “[W]e recognize that outdoor cats predate on wildlife and that we want to see a reduction in outdoor cats to help both wildlife and for the cats.”

Leash training

“While indoor cats use an average of 40 square yards in their home, community cats are natural hunters who have been known to roam up to 150 acres,” writes Jeannine Berger, one of the few veterinarians who is board-certified by both the American College of Veterinary Behaviorists and the American College for Animal Welfare.

“But this far-reaching outdoor life comes with risks. In fact, outdoor cats live only half as long as indoor-only cats, due to exposure to cat fights, infectious diseases, and injuries,” she writes. “Because of these dangers, veterinarians encourage pet parents not to let their cats roam freely outside. This is where a harness comes in. Harnessing a cat and walking them on a leash lets them explore, enhances mental stimulation, and gives them ample exercise—all while keeping your kitty safe.”

Both catios and leash training allow cats to experience the sights and smells of the outside world without endangering them or wildlife. New York–based company Travel Cat features a blog (check their website or Instagram for announcements of their virtual summit events) sharing tips on safe and effective harness and leash training for cat owners.

Bird-safe collars

Simply placing a bell on your outdoor cat’s collar will give wild birds a chance to escape before being pounced on, as they will hear the bell as a cat approaches. It might only give them a second or two as a warning, but that may be enough time to fly away.

As Ada McVean of the McGill University Office for Science and Society points out, “a number of studies have looked at whether or not bells help prey escape from cats, and the general consensus is yes. Bells on collars seem to reduce the amount of prey caught by about half, which could be enough to no longer pose a threat to ecosystems.”

Another option is brightly colored collars, which songbirds can easily see, like the ones made by BirdsBeSafe.com, a product endorsed by the American Bird Conservancy, a nonprofit bird advocacy organization.

Trap-Neuter-Return and Contraception

While the subject of much debate, trap-neuter-return (TNR) programs aim to manage feral cat colonies over time and limit population growth by preventing reproduction. Critics argue that TNR does not go far enough to protect wildlife, as neutered outdoor cats still hunt. Still, humanely reduced or managed feral populations are better for birds than an increasing population. Some conservationists advocate for managed colonies being gradually phased out in favor of adoption or placement in enclosed sanctuaries. However, as Jenny Pierson of the Cat Museum of New York City points out, “The cat overpopulation crisis (in tandem with veterinary professional shortages) in cities like New York means that overburdened shelters and rescuers/foster organizations are often already at capacity—meaning TNR may be the only option available to help save birds.”

During the COVID-19 pandemic, spay and neuter surgeries for dogs and cats decreased, creating challenges for those managing cat populations. During this period, megestrol acetate (MA), a synthetic hormone, emerged as a solution: a short-term contraceptive available by prescription for unspayed female cats.

“Non-surgical methods of contraception and sterilization have long been a passion of mine,” said veterinarian Mike Greenberg, outreach programs director at Maddie’s Fund, a California-based nonprofit pet advocacy group, in 2020. “I hope for the day when we can say to our younger colleagues, ‘Yeah, it was crazy. We used to have to cut animals open and remove organs just to control fertility!’” Greenberg, who co-founded the Veterinary Care Accessibility Project, a nonprofit creating tools for data-driven decisions to improve access to vet care, added, “While megestrol acetate is certainly not the panacea, it is a tool in the toolbox.”

“MA has long been prescribed by American veterinarians to treat various medical conditions in both male and female cats with minimal side effects,” asserts Alley Cat Allies, a Maryland-based nonprofit cat advocacy organization. “But before [the COVID-19 pandemic], it has not been widely used in the United States as a contraceptive.”

“Using the lowest possible dosages, MA and MPA may… be used safely in pet queens as well as (in conjunction with TNR programs) for the control of feral cat colonies,” writes veterinarian Stefano Romagnoli, who teaches animal reproduction at the University of Padova in Italy, in a 2015 paper published in the Journal of Feline Medicine and Surgery.

Public Education

Raising awareness is crucial. Many people are unaware of the impact their pets may have on local ecosystems. Educational campaigns can encourage responsible pet guardianship (as opposed to “pet ownership,” which some experts argue can lead to abuse because pets are viewed as objects rather than individuals). Local elected officials and community leaders can promote indoor living for cats and advocate for wildlife-friendly policies at the community level.

A city council member might, for example, partner with a local animal shelter to launch a public awareness campaign called “Safe Indoors, Safe Wildlife.” The campaign could include social media posts, posters in parks, and community workshops promoting the benefits of keeping cats indoors—for both their health and the protection of local wildlife. That official could also sponsor a resolution recognizing the ecological impact of outdoor cats and encouraging residents to commit to indoor cat care.

Legislation and Policy

Some jurisdictions have begun to pass laws restricting the free-roaming of cats or requiring that pets be kept indoors or on leashes. Madison, Wisconsin, for example, requires that cats follow the same rules as pet dogs, and that means being leashed when they are outdoors. “You aren’t allowed to have an animal off your property without it being under your control,” said Madison and Dane County’s public health supervisor, John Hausbeck. The only way to do that with a cat is to put them on a leash.” While enforcement can be challenging, such laws reflect a growing recognition of the seriousness of the issue.

Society needs to address the hard reality that outdoor cats constitute the leading human-driven cause of bird mortality. While cats have been cherished companions to millions of humans over the millennia (including this author), their outdoor behavior conflicts directly with the health and survival of wild bird populations, and that has knock-on effects across ecosystems, including impacts on humans.

By understanding the scope of the threat and implementing humane, effective, and practical solutions, we can begin to strike a better balance—protecting our beloved pets and the vulnerable birds who share our environment. As stewards of domestic animals, wild animals, and natural ecosystems, we have a responsibility to act with foresight and compassion for all species who call Earth home.

Dauphine and Cooper, the ecologists at the University of Georgia who warned of bird extinctions caused by free-roaming cats in 2008, co-wrote another paper three years later. Its title encapsulates this zero-sum game that we are playing with the natural environment: “Pick one: outdoor cats or conservation.” Clearly, we can’t have both.

[Author’s note: I am an enthusiastic cat lover, having participated in three feline “foster fails.” Also, as co-founder and board member of the Cat Museum of New York City, I am a dedicated cat advocate. I am also a longtime avian advocate and volunteer with NYC Bird Alliance, New York City Pigeon Rescue Central, and the Wild Bird Fund to rescue sick and injured wild birds. Cats and birds may not get along; I love them both. Special thanks to avian expert and fellow Observatory author Jim Cubie and Cat Museum of New York City executive director and fellow Observatory co-founder Jenny Pierson for their help with this article.]

Reynard Loki is a co-founder of the Observatory, where he is the environment and animal rights editor. He is also a writing fellow at the Independent Media Institute, where he serves as the editor of Earth | Food | Life. This article was produced by Earth | Food | Life, a project of the Independent Media Institute.