By SARAH BOWMAN
The Columbus Dispatch
The cardinal that feeds in your backyard is in jeopardy. So are the robins, warblers and migratory birds that call Ohio home for at least part of the year.
The culprit? Those cats you see roaming the neighborhood.
In fact, these felines are stone-cold killing machines, according to new research.
A study published yesterday in the journal Nature Communications estimates that cats kill as many as 3.7 billion birds and 20.7 billion mammals in the United States each year. The mammals include mice, rats, voles and chipmunks. The majority are killed by feral cats. The study’s estimates are much higher than previous studies have suggested.
Ohio is feeling the impact, said Jim McCormac, an avian expert with the Ohio Division of Wildlife. He said birds play a huge role in the ecosystem, and cats are throwing things out of balance.
“Birds are pest-control agents,” McCormac said. “So if there were no warblers, for example - a huge bird population that comes through Ohio - caterpillars would run completely amok, and we’d have an ecological catastrophe on our hands.”
Scientists from the Smithsonian Conservation Biology Institute and U.S. Fish and Wildlife Service performed the research and concluded that cats are the single-greatest source of bird and mammal mortality, out-killing all other sources combined.
The study is based on a review of 90 previous studies and offers the most comprehensive analysis of information on this issue, according to the researchers.
The loss of birds also affects Ohio’s economy, said Kim Kaufman, director of the Black Swamp Bird Observatory in northwestern Ohio. She said bird-watchers bring more than $30 million to the lake-shore area each spring.
“The bird migration through here is really spectacular and a wonderful thing for tourism, so these cats could have a significant impact on the global species that pass through Ohio on their migration,” Kaufman said.
A 2010 University of Nebraska Extension study estimated that cats cause $17 billion a year in damages to bird-watchers, hunters and wildlife. The $17 billion is based in part on estimates that the 60 million stray and feral cats that live in the United States kill six to eight birds per year. There are as many as 88 million domestic cats, many of which spend time outdoors.
Donald Burton, a veterinarian and CEO of the Ohio Wildlife Center, said cat attacks are the leading cause of admissions for the 5,000 animals the center treats each year.
Burton, Kaufman and McCormac said there is an easy solution: Keep cats indoors. All three said they own cats but don’t allow them outdoors.
“Once a cat enters the outdoors, it becomes an invasive species because they don’t have a natural role in our ecosystem,” McCormac said.
Linda Granger, a Granville resident, said her cat, Woody, brings home birds and rabbits.
“I don’t like that he hunts, but he was a feral cat and we saved him,” she said. “Once they start hunting, they have a desire to do that.”
Granger, who also has two indoor cats, said Woody was neutered.
Burton said licensing regulations should be as strict on cats as they are on dogs, which are not allowed to roam free.
Feral cats are a harder problem to tackle, Kaufman said. She said people should think twice about feeding them.
“I know it’s easier to relate to cats that we take into our homes as pets than to small birds people often never see, so we need to give these birds a voice, too,” Kaufman said.