The controversial issue of outdoor cats and their effect on wildlife just got a major boost in visibility. More than 200 wildlife protection groups, wildlife rehabilitation organizations, and university biology departments have signed a letter urging Interior Secretary Sally Jewell to remove colonies of feral cats from public lands.
Though both feral and owned cats kill wildlife, says the letter, feral cats account for about two-thirds of the total mortality of birds, mammals, reptiles, and other animals directly caused by outdoor cat predation.
"The number of domestic cats in the United States has tripled over the last 40 years and continues to rise," said George Fenwick of the American Bird Conservancy (ABC), one of the letter's signatories. "We are asking Secretary Jewell to take actions that will protect our native wildlife from 150 million feral and outdoor cats that are decimating wildlife populations in the most sacrosanct of locations, such as wildlife refuges, national parks, and other important public lands."
The letter, sent in late January, was announced in an ABC press release today. Among the more than 200 signatories were local Audubon and other wildlife protection groups. California-based signers of the letter include the Los Angeles Audubon Society and more than a dozen other local Audubon chapters throughout the state, the Citizens Committee to Complete the Refuge, the Garberville-based Environmental Protection Information Center (EPIC), the Klamath Forest Alliance, the Walnut-Creek-based Lindsay Wildlife Museum, and the Natural History Museum of Los Angeles County.
The letter's assessment of the threat to wildlife from outdoor domestic cats, both feral and owned, is bleak:
As the Smithsonian Institution and [the U.S. Fish and Wildlife Service] have found, there is great urgency due to the high mortality wildlife populations face. A peer-reviewed study by scientists from these two organizations estimated that approximately 2.4 billion birds and 12.3 billion mammals are killed in the United States by cats every year. While both owned and un-owned cats contribute, un-owned (e.g., feral) cats are responsible for over two-thirds of these bird deaths and nearly 90 percent of mammal deaths. Cats are now the number one source of direct anthropogenic mortality for birds and mammals, and their impact on wildlife will only increase as the numbers of cats - which have tripled in the last 40 years - continue to rise.
The groups urge Jewell to ensure that all agencies within the Interior Department develop a "clear policy" of removal of cat colonies on lands they manage. That would include National Wildlife Refuges run by the U.S. Fish and Wildlife Service, as well as National Parks and National Monuments, National Forests, and almost 250 million acres of land overseen by the Bureau of Land Management.
In a passage that's bound to attract criticism from feral cat fanciers, the groups criticize the commonly used technique of "Trap, Neuter and Return" (TNR) in which ferals are sterilized and then re-released and (sometimes) fed by caretakers.
TNR programs fail to reduce cat populations and cannot be relied upon as a management tool to remove cat colonies or protect people and wildlife. Multiple peer-reviewed studies, including the CDC's, have found that TNR programs do not adequately reduce feral cat populations or effectively mitigate health concerns. TNR colonies may actually lead to increased numbers of cats. One long-term study of TNR in Rome, Italy, went so far as to call TNR a "waste of money, time, and energy." The only sure way to simultaneously protect wildlife and people is to remove feral cats from the landscape.
"Domestic cats have been either a direct or indirect factor in 33 bird species extinctions and have been identified by the science community as one of the world's worst invasive species," said Susan Elbin of the New York City Audubon Society, one of the signers of the letter. "Rational heads have prevailed in terms of how stray dogs are treated. Stray cats should be treated much the same way. Turning a blind eye to this problem will only perpetuate the escalating impacts to birds and other wildlife, as well as threaten human health and safety."