New Studies Highlight Impact of Outdoor Cats on Birds and Other Wildlife

from Wildlife Promise

Domestic cat by Sherry and Brian Wood

The animals make great pets, but outdoor cats, whether feral or tame, kill more than a million birds a day in the United States alone. Photo by Sherry and Brian Wood.

This week–National Wildlife Week–scientific organizations announced two new studies that provide more evidence of the havoc outdoor cats wreak on wild birds and other wildlife.

“Crime Against Nature”

On March 15, The Wildlife Society said it was “taking a strong stand in favor of keeping pet cats indoors and removing feral cats from the environment to protect wildlife from cat predation.”

As part of this effort, the spring 2011 issue of the organization’s magazine, The Wildlife Professional, features a series of articles, “In Focus: The Impacts of Free-Roaming Cats.” The articles highlight problems that outdoor, stray and feral cats cause for wildlife and wildlife habitat as well as for animal and human health.

Among The Wildlife Society’s findings:

  • The number of free-roaming cats is increasing, currently between 117 million and 157 million in the United States alone. The domestic cat, Felis catus—a nonnative species—is now the most abundant carnivore in North America.
  • While cat numbers are rising, nearly one-third of more than 800 U.S. bird species are endangered, threatened or in significant decline.
  • By some estimates, outdoor cats in the United States kill more than 1 million birds every day on average. Other studies suggest the death toll is as high as 1 billion per year.
  • Outdoor cats transmit rabies, toxoplasmosis, typhus, plague and other viral and parasitic diseases to both wildlife and humans.

According to the society’s executive director, Michael Hutchins: “Allowing free-ranging pet and feral cats to roam outside, breed unchecked, kill native wildlife and spread disease is a crime against nature.”

The #1 Predator for Catbirds? Cats.

Another new study, on the effects of urbanization on wildlife and published in the Journal of Ornithology, tracked the early lives of gray catbirds in three suburbs of Washington, DC. Conducted by Peter Marra and Thomas Ryder of the Smithsonian Institution and Anne L. Balogh of Towson University, the study involved affixing very small radio transmitters to 69 newly hatched gray catbird chicks. The transmitters recorded the birds’ locations every other day until the animals left the study area or died.

Of the 42 young catbirds that did die, nearly 80 percent were killed by predators, and domestic cats were responsible for nearly half the known predation.

“While this study was not national in scope, it certainly adds more validation to what we’ve been saying for years: that outdoor cats are a highly destructive predatory force that is causing havoc in the world of native wildlife,” says Darin Schroeder, vice president for conservation advocacy at the American Bird Conservancy, an organization that has long advocated keeping cats inside.

Read a Washington Post commentary from Peter Marra, one of the authors of the cat-catbird study.

Learn how to keep your indoor pets entertained by setting up a bird-watching station for cats.

Do more to help local wildlife by making your yard an National Wildlife Federation Certified Wildlife Habitat.

Find out about National Wildlife Week, NWF’s longest-running education program, happening March 14-20, 2011.