Outdoor cats kill 60 million birds in Canada each year, study finds

Abdul Matin SarfrazCanada’s National ObserverLocal Journalism Initiative April Campbell has five rescue cats at home in Toronto and a bird feeder in her backyard. She loves watching the birds but also cares deeply for her foster cats. To protect both, she built a “catio” — a secure outdoor enclosure where cats can enjoy sun and fresh air without hunting wildlife. She doesn’t want her pets contributing to the millions of bird deaths caused by outdoor cats each year. “I love cats but I also love birds. I love all animals,” she said. “We can give cats everything they need indoors. They do not have to be outside hunting. With a catio, they can explore and relax and the birds in my yard stay safe.” Her house is full of toys, climbing shelves, scratching posts and quiet spots — all meant to keep the cats active without roaming. If more cat owners took the same approach, the number of birds killed each year could drop to almost zero, according to a new study from the University of Guelph. The study estimates that 3.5 million cats spend time outdoors in Canada and together they kill a median of 60 million birds every year. Bird populations in North America have already fallen by more than three billion since 1970 due to habitat loss and climate change. Lead researcher Jonathan Chu told Canada’s National Observer most cat owners never see the true number of birds killed. “Cats don’t typically bring home all their prey, so they may kill four or five birds, but only return one to their owner,” the report says. To understand the real impact, some of the studies Chu’s team reviewed used small cameras on cats to record what happens outside. That footage showed many more kills than owners reported. The team reviewed 58 studies on cat predation and five studies on outdoor cat populations to update Canada’s bird mortality estimate. Instead of using a single calculation, they ran thousands of simulations using different estimates for cat numbers and kill rates. This produced a median estimate of 60 million bird deaths within a range between 19 million and 197 million. The last national estimate of cat predation rates and killing birds was made in 2013, but Chu says much more data has become available since then, making this update more accurate. Cats are now the most popular pet in Canada, recently surpassing dogs. Chu says while no one lets dogs roam unsupervised, many people still believe cats should be free to wander. But cats are highly skilled predators by nature, regardless of whether they are hungry. “They are descended from carnivorous hunters. Some cats will hunt for food, but many well-fed pet cats still hunt simply because it is an instinct,” he said. The study looked at three types of cats outdoors in Canada: Urban-owned cats — pets allowed to roam in cities; rural-owned cats — barn and farm cats with outdoor access; and feral or stray cats living full-time outside. Urban-owned cats made up about 71 per cent of the outdoor cat population estimate and accounted for about half of all bird deaths. Stray and feral cats made up a smaller portion of the population — roughly 20 per cent— but because they spend all their time outside, they were estimated to be responsible for about 30 per cent of bird kills. Chu said many cats hunt more often at night or during early morning and evening. Most birds killed were young birds learning to fly. Nest attacks were rare but documented. Cats were first domesticated about 9,000 years ago, and are found today on every continent except Antarctica. Researchers say pet and feral cats are now one of the most widespread predators on the planet. A global study in Nature Communications found that cats kill more than 2,000 different species, including nearly 1,000 bird species — many already at risk. Their prey list also includes mammals, reptiles, insects and amphibians. The study recorded cats eating 981 bird species, 463 reptiles, 431 mammals, plus insects and frogs, showing how wide their impact is on wildlife. Chu says cats are not the only threat but they are a direct one, so the most effective way to reduce bird deaths is to keep cats indoors, which brings their wildlife impact to zero. For owners who find that difficult, he suggests catios, leashes, shorter outdoor time or supervision. Reflective collars may help birds detect cats sooner, though they do not protect small mammals. However, some farmers say barn cats help keep mice and rats away from stored grain and feed, protecting crops and supplies. Some Canadian cities have introduced bylaws to limit free-roaming cats, but enforcement is weak, Chu says. Still, he believes these rules matter because they set a standard. He says microchipping, registration and clear ownership rules paired with public education could help shift behaviour and make cat owners more responsible. Chu says cats are loved in Canada and any solution must respect that connection. He believes people can care for their pets while also protecting wildlife. Campbell, a board member with Annex Cat Rescue — a volunteer-run Toronto group that helps street cats through a trap-neuter-return program, fostering and adoption — believes cat owners can be part of the solution. The rescue asks adopters to keep cats indoors or use a safe enclosure such as a catio. “It keeps birds safe, but it also protects cats from cars, disease and coyotes,” she says. For cats without owners, she supports trap-neuter-return — catching, sterilizing and returning cats to managed colonies. “It’s the only humane way to reduce the population.”