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The Wisconsin Study: Bad Science Costs Cats’ Lives

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As the leading advocate for the humane treatment of cats in America, we are continually dismayed and appalled to see opponents of Trap-Neuter-Return threaten cats’ lives by using flawed science to wrongly blame cats for the declining wildlife populations. Nowhere is this more common than with the “Wisconsin Study,” an unpublished research proposal for a study of the number of cats in rural Wisconsin.

The Wisconsin Study has never been peer-reviewed and only parts of it have been selectively published. The numbers from this proposal have been disavowed by one of its own authors, yet major organizations including the American Bird Conservancy1 and even the U.S. Fish and Wildlife Service2 have carelessly and dangerously wielded these flawed statistics when discussing Trap-Neuter-Return. Such high-profile organizations have a responsibility to properly examine their sources and provide Americans with scientifically-supported information.

When they don’t, bad science is unknowingly perpetuated by an oblivious media and abused by biased lobbies. In the case of the Wisconsin Study, both the New York Times3 and the Los Angeles Times4 failed to investigate the accuracy of the Wisconsin numbers, as did the wind power industry.5 As the false data circulates, people aren’t getting the truth about cats.

The Wisconsin Study is not reliable scientific research. The irresponsible circulation of these numbers endangers cats’ lives—and it has to stop.

Where the Wisconsin Numbers Went Wrong

A quick look at the history of the Wisconsin Study reveals that the authors have extrapolated their findings from a survey of residents of rural Wisconsin into wild speculation about the impact of cats on wildlife nationwide—based almost entirely on data not vetted by the scientific community.

  • In 1993, the authors published their projections of the numbers of free-roaming cats in rural Wisconsin in The Wildlife Bulletin. This is the only data from the Wisconsin Study ever to undergo peer review. It does not measure or estimate cat predation at all.6
  • Two years later, in the non-reviewed trade magazine Wildlife Control Technologies, the authors combined unpublished data from the Wisconsin Study with data that was 40-60 years old at the time, in a clearly unreliable attempt to estimate the proportion of cats’ prey that are birds.7
  • The following year, in Wisconsin Natural Resources Magazine, they used this unscholarly, unscientific estimate to make “best guesses” at low, medium, and high numbers of bird deaths attributable to cats annually—failing to mention that their estimates were based on unpublished numbers.8
  • In 1999, the authors took these “guesses” and presented them (again without acknowledging their dubious origins) in Wildlife Control Technologies—the same trade magazine where they had first distorted the study’s findings using old and unpublished data. From their projections of the number of cats in rural Wisconsin, they now broadly concluded:
    “Rural free-ranging domestic cats in Wisconsin may be killing between 8 and 217 million birds each year… Nationwide, rural cats probably kill over a billion small mammals and hundreds of millions of birds each year.”9
  • When interviewed, Dr. Stanley Temple, co-author of the Wisconsin Study articles, later disavowed the estimates of cat predation saying, “Those figures were from our proposal. They aren’t actual data; that was just our projection to show how bad it might be.”10

Mutant Statistics

The term “mutant statistics,” originated by sociologist Joel Best, refers to statistics that have been stretched, manipulated, and distorted until they can no longer be concluded from the original studies that produced them.11 This is what has happened with the Wisconsin Study—its findings have become a mutant statistic. Over time, the authors have taken a small nugget of scientifically valid, peer-reviewed research—the number of cats in rural Wisconsin—and intentionally manipulated it into a much larger, broader statement about a contentious issue—the number of animal deaths attributed to cats nationwide. This number is so unreliable and unscientific, even the study’s co-author can’t stand behind it.

Bad Science Costs Cats’ Lives

We can’t make decisions about animals’ best interests based on flawed research—based on, as Dr. Temple says, what might be.

Sadly, that is exactly what opponents of Trap-Neuter-Return ask community members and policymakers to do every time they dredge up the faulty Wisconsin Study. Whether they are intended to mislead or reprinted through careless research, citing these mutant statistics pollutes the scientific body of research and the public opinion regarding cats and wildlife, costing countless cats their lives.

It’s time to put the tired Wisconsin numbers to bed and start looking at the real science—that cats are not a threat to wildlife and Trap-Neuter-Return is the effective approach for managing feral cat colonies.


[1] American Bird Conservancy, “Domestic Cat Predation on Birds and Other Wildlife.” n.d., American Bird Conservancy: The Plains, VA. http://www.abcbirds.org/abcprograms/policy/cats/materials/predation.pdf. (accessed April 6, 2011).
[2] U.S. Fish and Wildlife Service. “Division of Migratory Bird Management - Cat Predation.” June 1, 2009. http://www.fws.gov/migratorybirds/CurrentBirdIssues/Hazards/CatPredation.html (accessed May 26, 2010).
[3] Barcott, Bruce. “Kill the Cat That Kills the Bird?” New York Times. 2007: New York. http://www.nytimes.com/2007/12/02/magazine/02cats-v–birds-t.html. (accessed April 6, 2011).
[4] Kennedy, J. Michael. “Killer Among Us.” Los Angeles Times. 2003: Los Angeles. http://articles.latimes.com/2003/dec/23/news/os-cat23. (accessed April 6, 2011).
[5] Sagrillo, Mick. “Wind turbines and birds: Putting the situation in perspective in Wisconsin.” Wisconsin Focus on Energy 2007. http://www.focusonenergy.com/files/Document_Management_System/Renewables/windturbinesandbirds_factsheet.pdf . (accessed April 6, 2011).
[6] Coleman, John S., and Stanley A. Temple. "Rural Residents' Free-Ranging Domestic Cats: A Survey." Wildlife Society Bulletin 21 (1993): 381-390.
This article “surveyed farmers and other rural residents in Wisconsin for information about their free-ranging (not house-bound) cats” and “profiled rural residents’ attitudes towards cats and determined the number of free-ranging cats on rural properties and the factors that affected their densities” in an attempt to gauge the number of cats in rural Wisconsin. It did not measure predation or review any information that would enable the authors to estimate the effect that cats might be having on Wisconsin wildlife.
[7] Coleman, John S., and Stanley A. Temple. "How many birds do cats kill?" Wildlife Control Technologies, July/August 1995: 44.
[8] Coleman, John S., and Stanley A. Temple. "On the prowl." Wisconsin Natural Resources, December 1996.
The non-peer-reviewed Wisconsin Natural Resource magazine instructs its authors that “…Wisconsin Natural Resources is not a technical journal for researchers. Only cite research results to make a point and give readers some insight. Cut through years of research and give them the gist. They are not interested in methodology; they want to know what you learned and what your research implies for managing resources.”
[9]Coleman, John S., Stanley A. Temple, and Scott R. Craven. "Cats & wildlife: a conservation dilemma." Wildlife Control Technologies, January/February 1999: 18-20.
[10] As quoted in “The Accused,” by Jeff Elliott, Sonoma County Independent, March 3-13, 1994. Emphasis in the original.
[11] Best, Joel. Damned Lies and Statistics. Berkeley, CA: University of California Press, 2001.