A new study from scientists at the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service raises concerns about the welfare of Vermont’s wildlife populations. The study found that cats are the single greatest cause of human-caused mortality to birds and mammals, killing an estimated average of 2.4 billion birds and 12.3 billion mammals each year in the United States.
“Cats pose a threat to Vermont’s songbirds, such as robins, bluebirds and cardinals,” said Vermont Fish & Wildlife bird biologist John Buck. “Cats may even restrict the statewide recovery of some rare birds. The whip-poor-will, which is a state threatened species, can easily fall prey to roaming cats during their nesting season.”
In addition to lowering populations of species enjoyed by birdwatchers, cats can depress populations of other species that Vermonters value such as ducks, rabbits, and hares. To mitigate these effects, biologists in the prairie pothole region of northcentral United States post fences around duck nesting areas to exclude cats and other predators from killing the ducklings.
“This is more of a pervasive problem for wildlife than many people realize,” said Fish & Wildlife biologist Steve Parren. “It was a wakeup call for my family when our friendly tabby delivered a still struggling baby bunny to our doorstep. We realized the potential consequences of allowing our cat to roam outdoors.”
According to the study, feral cats account for a significant portion of the deaths. To prevent contributing to feral cat populations, the Fish & Wildlife Department recommends that pet owners spay or neuter their cats to prevent unwanted litters. The department also recommends pet owners consider keeping indoor cats, both for the protection of wildlife and for the health of their pet.
“The lifespan of an indoor cat is roughly double that of an outdoor cat,” said Stowe veterinarian Dr. Richard Levine. “Infectious disease is almost non-existent in indoor cats, whereas outdoor cats are at risk for things like intestinal parasites, trauma from cars, and bites and scratches from other cats. Keeping an outdoor cat can increase the veterinary costs for pet-owners by hundreds or even thousands of dollars over the lifetime of the animal.”
“When you allow your cat to wander freely in nature, your cat becomes a part of the food chain,” added Parren. “Sadly, many people’s pets fall prey themselves to larger predators such as coyotes, fishers, and foxes.”