Feral Cat Problem

January 28, 2014

The Honorable Sally Jewell


U.S. Department of the Interior

Washington, D.C. 20240

Dear Secretary Jewell,

On behalf of the undersigned conservation organizations, we urge swift action to address the threat to wildlife populations and human health posed by feral cats.

In the past year, a series of new scientific studies have been published documenting extensive wildlife mortality resulting from cat predation, growing risk to human health from rabies and toxoplasmosis spread by cats, and the ineffectiveness of trap, neuter, release (TNR) programs at stemming cat populations. As Secretary, you are in a position to direct action to conserve wildlife and to adopt land management policies that will ensure public lands are not degraded by the presence of cat colonies.

This issue was raised with the Department in an attached April 12, 2011, letter to Secretary Ken Salazar. To date, while discussions with Department of the Interior or U.S. Fish and Wildlife Service (FWS) staff have taken place, no meaningful actions needed to address this problem have been taken by the Department.

As the Smithsonian Institution and FWS 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.1 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.

Most recently, the Centers for Disease Control and Prevention (CDC) has determined that feral cat colonies pose a threat to human health. According to the CDC, cats are consistently the number one carrier of rabies among domestic animals and disproportionately pose a risk of human exposure to rabies because of the increased likelihood of human-cat interactions.

A recently published study led by CDC scientists stated, “The propensity to underestimate rabies risk from cats has led to multiple large-scale rabies exposures.”3 Continued tolerance for roaming feral cats is, according to the Florida Department of Health, “not tenable on public health grounds because of the persistent threat posed to communities.”

Toxoplasmosis also threatens the health and welfare of people and wildlife. This disease is caused by a parasitic protozoan that depends on cats to complete its life cycle. Up to 74 percent of all cats will host the toxoplasmosis-causing parasite in their lifetime and shed hundreds of millions of infectious eggs as a result.6 Any contact, either directly or indirectly, with cat feces risks human and wildlife health. In humans the parasite often encysts within the brain, which may cause behavioral changes and has been linked to schizophrenia, Alzheimer’s, and other neuro-inflammatory diseases.7 Pregnant women may suffer sudden abortion or fetal developmental defects (e.g., blindness).6 Wildlife are similarly at risk, and contamination of watersheds with infected cat feces has been linked to the deaths of a number of freshwater and marine species (e.g., otters, Hawaiian monk seals).

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.

Cat colonies are a common problem on many federal lands managed by the Department of the Interior. We urge that each agency develop a clear policy for the removal of cat colonies on the federal lands they are responsible for stewarding.


Accipiter Enterprises, Educational Birds of Prey

Alaska Wild Animal Recovery Effort Inc.

Allamakee County Protectors

Allegheny Highlands Alliance

Alliance for the Wild Rockies

American Bird Conservancy

American Birding Association

American River Parkway Foundation

Anne Arundel Bird Club

Audubon Minnesota

Audubon Naturalist Society

Audubon Society of Kalamazoo

Audubon Society of New Hampshire

Audubon Society of Northern Virginia

Audubon Society of Rhode Island

Bexar Audubon Society

Bird Ally X

Bird City Wisconsin

Bird Conservation Network

Black River Audubon Society

Black Swamp Bird Observatory

Bridgerland Audubon Society

Central New Mexico Audubon Society

Central Valley Bird Club

Centre Wildlife Care

Chesapeake Audubon Society

Chicago Audubon Society

Chicago Bird Collision Monitors

Chicago Ornithological Society

Citizens Committee to Complete the Refuge

12 Natoli E., L. Maragliano, G. Cariola, A. Faini, R. Bonnani, S. Cafazzo, and C. Fantini. 2006. Management of feral domestic cats in the urban environment of Rome (Italy). Preventive Veterinary Medicine 77: 180-185.

Clearwater Audubon Society

Coastal Bend Audubon Society

Coastal Virginia Wildlife Observatory

Colorado Wild Rabbit Foundation

Connecticut Audubon Society

Cornell Lab of Ornithology

Coulee Region Audubon Society

Delmarva Ornithological Society

Department of Fisheries and Wildlife, Oregon State University

Desert Rivers Audubon Society

Detroit Audubon Society

Eastern Long Island Audubon Society

Elisha Mitchell Audubon Society

Endangered Habitats League

Environmental Protection Information Center (EPIC)

Evergreen Audubon

Five Valleys Audubon Society

Flathead Audubon

Florida Keys Hawkwatch

Florida Wildlife Federation

Foothills Audubon Club

Freedom Center for Wildlife Inc.

Friends of Atascadero Wetlands

Friends of Beautiful Pendleton County

Friends of Dyke Marsh

Friends of the Kalmiopsis

Friends of the Tampa Bay National Wildlife Refuges

Georgia Important Bird Areas Conservation Program

Georgia Ornithological Society

Geos Institute

Golden Eagle Audubon Society

Grand Valley Audubon Society

Great South Bay Audubon Society

Greater Ozarks Audubon Society

Greater Wyoming Valley Audubon Society

High Country Audubon Society

Hilton Pond Center for Piedmont Natural History

Hope Valley Audubon Society

Houston Audubon

Howard County Bird Club

Hoy Audubon Society

Huntington-Oyster Bay Audubon Society

Idaho Conservation League

Illinois Audubon Society

Illinois Ornithological Society

Ivy Creek Natural Area

John Burroughs Natural History Society

Juniata Valley Audubon Society

Kalmiopsis Audubon Society

Kansas Wildlife Federation

Kerncrest Audubon Society

Kettle Range Conservation Group

Kissimmee Valley Audubon Society

Klamath Forest Alliance

Lab of Avian Biology – University of Maine

Lahontan Audubon Society

Lake County Audubon Society

Lake-Cook Audubon

Lane County Audubon

Lehigh Valley Audubon Society

Lindsay Wildlife Museum

Los Angeles Audubon Society

Madison Audubon Society

Madrone Audubon Society


Manistee Audubon

Maricopa Audubon Society

Maryland Ornithological Society

Maryland/Delaware Chapter of The Wildlife Society

Mid-Coast Audubon Society

Minnesota Chapter of The Wildlife Society

Minnesota Herpetological Society

Minnesota River Valley Audubon Chapter

Monmouth County Audubon Society

Montana Audubon

Montana Falconers Association

Montana Fish, Wildlife, and Parks

Montgomery Friends of Open Space

Mt. Diablo Audubon Society

Native Songbird Care & Conservation

Natural History Museum of Los Angeles County

New Hampshire Audubon

New Jersey Association of Wildlife Rehabilitators

New Jersey Audubon

New York City Audubon Society

New York State Wildlife Rehabilitation Council

North Carolina Chapter of The Wildlife Society

North Dakota Birding Society

Northern Flint Hills Audubon Society

Oconee Rivers Audubon Society

Ohlone Audubon Society

On A Wing And A Prayer

Otter Creek Audubon Society

Pamela Jo Hatley Professional Association

People for the Ethical Treatment of Animals

Peregrine Audubon Society

Pomona Valley Audubon Society

Progressive Democrats, Sonoma County

Queens County Bird Club Inc.

Quick Reference Publishing

Rainforest Biodiversity Group

Ralph T. Waterman Bird Club

Redbud Avian Rehabilitation Center, Inc.

Redwood Region Audubon Society

Robert Cooper Audubon Society

Sacramento Audubon Society

Salem Audubon Society

San Diego Audubon Society

San Francisco Bay Joint Venture non-federal partners

Sangre de Cristo Audubon Society

Santa Barbara Audubon Society

Santa Clara Valley Audubon Society

Sassafras Audubon Society

Save Our Allegheny Ridges

Save Our Cabinets

Saving Birds Thru Habitat

Seattle Audubon Society

Sequoia Audubon Society

Shadow Oaks Wildlife Care

Skagit Audubon Society

Soda Mountain Wilderness Council

SoHo Dogs Inc.

Songbird Care and Education Center

South Bend-Elkhart Audubon Society

South Florida Audubon Society

Southeastern Arizona Bird Observatory

Southern Adirondack Audubon Society

Southwestern New Mexico Audubon Society

St. Louis Audubon Society

St. Lucie Audubon Society

Stockbridge Audubon Society

Tampa Audubon Society

Tennessee Chapter of Sierra Club Tennessee Ornithological Society

The Biodiversity Group

The Institute for Bird Populations

The Nature Conservancy - Kentucky Field Office

The Rural Alliance

The Trumpeter Swan Society

The Wildlife Center of Virginia

Tippecanoe Audubon Society

Virginia Beach SPCA Wildlife Program

Virginia Bluebird Society

Virginia Society of Ornithology

Wabash Valley Audubon Society

Warioto Audubon Society

Weeden Foundation

Western Nebraska Resources Council

Whitescarver Natural Resources Management LLC

Wild Utah Project

Wildbird Recovery

Wildlife Care Alliance

Wildlife Care Association

Wildlife Center of Silicon Valley

Wildlife Emergency Services

Wildlife Rehabilitation and Release

Wildlife Research and Consulting Services LLC

Will County Audubon Society

Winnebago Audubon Society

Wisconsin Audubon Council

Wisconsin Society for Ornithology

World Safaris/Safari Professionals

Wyncote Audubon Society

Yellowstone to Uintas Connection

Yellowstone Valley Audubon Society

York Audubon Society

Yosemite Area Audubon Society

Youth Environmental Alliance

Zumbro Valley Audubon Society