GAINESVILLE, Fla., May 2 (UPI) -- A study shows that colonies of wild, untamed house cats are a threat not only to small animals but also the creatures that prey on them.
Many of the animals used for prey are on the endangered species list, the research found. The study was conducted by the University of Florida for the U.S. Fish and Wildlife Service and released Friday.
The number of feral cats in the United States is estimated to be 40 million to 60 million, said Pamela Hatley, a law student who conducted the study for the university's Conservation Clinic. Another 40 million cats live at homes but also roam outside, hunting and killing small animals.
"The domestic cat species is not indigenous to Florida or anywhere else in North America," she said. "They impact native wildlife in three primary ways: predation, competition and disease."
One of the major problems is that humans, avoiding the guilt of euthanizing the cats, have been supporting large colonies with funding and other resources.
The practice is called trap-neuter release in which feral cats are spayed or neutered and returned to colonies where caretakers take care of them.
Although the programs are designed to reduce wild cat populations, irresponsible pet owners continue to release unwanted cats that join feral cat colonies, Hatley said.
There are laws against releasing domestic pets into the wild, but they are not enforced.
In Florida such colonies are known to exist in 17 of 67 counties. The largest, in Key Largo, Fla., may include as many as 1,000 cats and operates on an annual budget of $100,000.
One example is the Lower Florida Keys marsh rabbit, an endangered species with a remaining population of about 100-300. A 1999 study found cats were responsible for 53 percent of the deaths of the rabbits in one year. A 2002 study indicates the species could be extinct within two or three decades.
Cats also have been recognized as a serious threat to the Key Largo cotton mouse, Key Largo wood rat, Choctawhatchee beach mouse, Perdido Key beach mouse, green sea turtle, roseate tern, least tern and Florida scrub jay.
Feline predators also are a serious problem in California and Hawaii. Those states, like Florida, have a climate that is ideal for cats to survive outside and breed year-round.
As a result, endangered animals such as the Hawaiian goose, California brown pelican and blunt nosed leopard lizard also are under attack by cats.
Another problem is higher up the food chain.
"Cats are non-indigenous predators that compete in the wild with native predators like owls, hawks, fox," Hatley said. "Because cats, being subsidized by humans, outnumber these native predators and prey on the same mammals and birds.
"Thus, cats reduce the prey base for native predators, making it difficult for native predators to feed themselves and their young," she said.
Disease is another problem.
The Centers for Disease Control and Prevention reports that rabies is more than twice as common in cats as it is in dogs, and cats have the highest incidence of rabies among domestic species.
"It is essential that our state and local governments take steps to educate the public about the destructive impact of free-roaming cats on native wildlife and strictly enforce against the release of cats into the wild," Hatley said.
