January 21, 2014

The Honorable Sally Jewell
Secretary
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.1,2

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.3,4

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.”5

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).8,9,10

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. 4,11,12 TNR colonies may actually lead to increased numbers of cats.11, 12 One long-term study of TNR in Rome, Italy, went so far as to call TNR a “waste of money, time, and energy.”12

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.

Sincerely,

Allamakee County Protectors
American Bird Conservancy
Audubon Naturalist Society
Audubon Society of Kalamazoo
Audubon Society of Northern Virginia
Audubon Society of Rhode Island
Bird City Wisconsin
Bird Conservation Network
Black Swamp Bird Observatory
Bridgerland Audubon Society
Central New Mexico Audubon Society
Central Valley Bird Club
Centre Wildlife Care
Chesapeake Audubon Society
Clearwater Audubon Society
Connecticut Audubon Society
Delmarva Ornithological Society
Eastern Long Island Audubon Society
Elisha Mitchell Audubon Society
Endangered Habitats League
Evergreen Audubon
Five Valleys Audubon Society
Flathead Audubon Society
Foothills Audubon Club
Friends of the Kalmiopsis
Friends of the Tampa Bay National Wildlife Refuges
Georgia Important Bird Areas Conservation Program
Georgia Ornithological Society
Golden Eagle Audubon Society
Great South Bay Audubon Society
Greater Ozarks Audubon Society
Greater Wyoming Valley Audubon Society
High Country Audubon Society
Hope Valley Audubon Society
Hoy Audubon Society
Huntington-Oyster Bay Audubon Society
Illinois Ornithological Society
Ivy Creek Natural Area
Juniata Valley Audubon Society
Kettle Range Conservation Group
Kissimmee Valley Audubon Society
Lahontan Audubon Society
Lane County Audubon
Maryland Ornithological Society
Monmouth County Audubon Society
Montana Fish, Wildlife, and Parks
North Carolina Chapter of The Wildlife Society
North Dakota Birding Society
Ohlone Audubon Society
Otter Creek Audubon Society
Salem Audubon Society
Sangre de Cristo Audubon Society
Santa Barbara Audubon Society
Save Our Cabinets
Saving Birds Thru Habitat
Seattle Audubon Society
Skagit Audubon Society
Soda Mountain Wilderness Council
Southern Adirondack Audubon Society
Southwestern New Mexico Audubon Society
Stockbridge Audubon Society
St. Louis Audubon Society
St. Lucie Audubon Society
Tampa Audubon Society
Tennessee Chapter of Sierra Club
Tennessee Ornithological Society
The Institute for Bird Populations
The Nature Conservancy - Kentucky Field Office
The Wildlife Center of Virginia
Tippecanoe Audubon Society
Tufts Cummings School of Veterinary Medicine
UC Davis Wildlife Health Center
University of Tennessee College of Veterinary Medicine
Virginia Society of Ornithology
Weeden Foundation
Western Nebraska Resources Council
Whitescarver Natural Resources Management
Wildbird Recovery
Wisconsin Society for Ornithology
World Safaris/Safari Professionals
Wyncote Audubon Society
Yellowstone Valley Audubon Society
Yosemite Area Audubon Society

1 Loss S. R., T. Will, and P. P. Marra. 2013. The impact of free-ranging domestic cats on wildlife of the United States. Nature Communications 4:1396.
2 Lepczyk C. A., N. Dauphiné, D. M. Bird, S. Conant, R. J. Cooper, D. C. Duffy, P. J. Hatley, P. P. Marra, E. Stone, and S. A. Temple. 2010. What conservation biologists can do to counter trap-neuter-return: response to Longcore et al. Conservation Biology 24: 627-629.
3 Blanton J. D., J. Dyer, J. McBrayer, C. E. Rupprecht. 2012. Rabies surveillance in the United States during 2011. Journal of the American Veterinary Medical Association 241: 712-722.
4 Roebling A. D., D. Johnson, J. D. Blanton, M. Levin, D. Slate, G. Fenwick, and C. E. Rupprecht. 2013. Rabies prevention and management of cats in the context of Trap-Neuter-Vaccinate-Release programmes. Zoonoses and Public Health doi: 10.1111/zph.12070.
5 Florida Department of Health. 2013. Rabies prevention and control in Florida, 2013. Florida Department of Health, Tallahassee, http://www.floridahealth.gov/chdPasco/publications/Rabies/RabiesGuide2013Final.pdf.
6 Tenter A. M., A. R. Heckeroth, and L. M. Weiss. 2000. Toxoplasma gondii: from animals to humans. International Journal for Parasitology 30: 1217-1258.
7 Webster J. P., M. Kaushik, G. C. Bristow, and G. A. McConkey. 2013. Toxoplasma gondii infection, from predation to schizophrenia: can animal behavior help us understand human behavior? The Journal of Experimental Biology 216: 99-112.
8 Kreuder C., M. A. Miller, D. A. Jessup, L. J. Lowenstine, M. D. Harris, J. A. Ames, T. E. Carpenter, P. A. Conrad, and J. A. K. Mazet. 2003. Patterns of mortality in southern sea otters (Enhydra lutris nereis) from 1998-2001. Journal of Wildlife Diseases 39: 495-509.
9 Conrad P. A., M. A. Miller, C. Kreuder, E. R. James, J. Mazet, H. Dabritz, D. A. Jessup, F. Gulland, and M. E. Grigg. 2005. Transmission of Toxoplasma: clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment. International Journal for Parasitology 35: 1155-1168.
10 Honnold S. P., R. Braun, D. P. Scott, C. Sreekumar, and J. P. Dubey. 2005. Toxoplasmosis in a Hawaiina monk seal (Monachus schauinslandi). Journal of Parasitology 91: 697-699.
11 Castillo D. and A. L. Clarke. 2003. Trap/Neuter/Release methods ineffective in controlling domestic cat “colonies” on public lands. Natural Areas Journal 23: 247-253.
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.