Feral Cats Are Major Killers of Rats, Not Birds


Guest blog from researcher/author Anne E. Beall, Ph.D. is CEO of Beall Research, Inc. and the author of “Community Cats: A Journey into the World of Feral Cats.” Among her other books, “Strategic Market Research, 2nd Edition,” “Reading the Hidden Communications Around You” and co-author “The Operating Partner in Private Equity.” Beall is internationally respected as a researcher and strategist with clients around the world. 

“I recently read John Kass’s article Feral Cats, Rats and Songbirds form an unnatural mix in the Chicago Tribune.  John Kass talks about cats as if they are killing machines that are on the hunt to decimate bird populations 24 hours a day and who are highly unlikely to kill Chicago rats.  His inflammatory language is amusing but his facts are wrong.  Here are the actual facts from people who have studied this issue in depth.

Feral cats are excellent at killing rats. I say this as a feral cat caretaker who had a rat problem that was out of control in Lakeview. We had the Chicago Streets & Sanitation Dept. on speed-dial for a while. They came out almost once a week to put poison down rat holes.  That effort did nothing.  We also tried gassing them, pouring copious amounts of water and broken glass down their rat holes. Nothing worked until we imported a feral cat colony with with Tree House Humane Society, and their Cats at Work Project.  And contrary to Mr. Kass’s assertion, we did not find piles of dead birds around our yard. We did find a lot of dead rats. And then we stopped seeing rats altogether. Yes, feral cats do take on rats—even large Chicago ones.  We also found similar results in a survey we conducted of Americans nationwide; cats kill rats. (Beall, 2014)

But what about the claim that cats are the biggest killer of birds? We have seen some sensational claims such as one from a Smithsonian article that estimates that cats kill approximately 1.4 to 3.7 billion birds every year in the United States (Loss, Will, and Marra 2013).  However, these estimates have some major issues.  The first problem is that the total number of birds that cats are estimated to kill is implausible (Wolf 2013). The current number of birds who reside in the United States is 3.2 billion and in North America, 5.8 billion (Partners in Flight 2013). If cats were killing this many birds, they would be killing 43 to 100 percent of the U.S. birds each year. If that situation were an actuality, the bird population would be entirely wiped out within one to two years.

Research evidence shows that cats kill mammals (for example, rats and mice) more than they do birds (Crooks and Soulé 1999, Kays and DeWan 2004, Mitchell and Beck 1992). The question is, how many birds and which ones? Cats tend to prey on animals that are weaker and sicker because they are easier to catch (Baker et al. 2008, Moller and Erritzoe 2000). These scientific findings have led the Royal Society for the Protection of Birds to declare on its Web site, “Despite the large numbers of birds killed, there is no scientific evidence that predation by cats in gardens is having any impact on bird populations UK-wide. This may be surprising, but many millions of birds die naturally every year, mainly through starvation, disease, or other forms of predation. There is evidence that cats tend to take weak or sickly birds” (RSPB 2014).

What is killing the bird population?  We are: Habitat loss, global warming and collisions with buildings are killing birds more than cats. A recent article in the Washington Post claims that about 1 billion birds die annually in window collisions.  And according to the Cornell Lab of Ornithology (and many other experts),  (http://www.birds.cornell.edu/AllAboutBirds/conservation/planning/threats) the major threats to native birds are: habitat loss and degradation, increased numbers of competitors, exploitation (hunting, pets), chemical toxins, and pollution.  It’s time to take a look in the mirror and be honest about what’s killing birds.  We are.”


Baker, P. J., S. E. Molony, E. Stone, I. C. Cuthill, and S. Harris. 2008. “Cats about Town: Is Predation by Free-Ranging Pet cats Felis catus Likely to Affect Urban Bird Populations?” Ibis 150: Supplement 1, 86–99. http://www.ingentaconnect.com/content/bsc/ibi/2008/00000150/A00101s1/art00008.

Beall, A. E. (2014).  Community Cats.  Bloomington: iUniverse

Crooks, K. R. and M. E. Soulé. 1999. “Mesopredator Release and Avifaunal Extinctions in a Fragmented System. Nature 400: 563–66.

Kays, R.W. and A. A. DeWan. 2004. “Ecological Impact of Inside/Outside House Cats around a Suburban Nature Preserve. Animal Conservation 7: 273–83.

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.

Mitchell, J. C. and R. A. Beck. 1992. “Free-Ranging Domestic Cat Predation on Native Vertebrates in Rural and Urban Virginia. Virginia Journal of Science 43: 197–207.

Moller, A. P. and J. Erritzoe. 2000. “Predation against Birds with Low Immunocompetence.” Oecolgia 122 (4): 500–504.

Partners in Flight Science Committee. 2013. PIF Population Estimates Database, version 2.0 (2013). http://rmbo.org/pifpopestimates. Accessed on April 14, 2014.

Royal Society for the Protection of Birds (RSPB). 2014. “Are Cats Causing Bird Declines?” http://www.rspb.org.uk/advice/gardening/unwantedvisitors/cats/birddeclines.aspx. Accessed May 3, 2014.

Wolf, P. J. 2013. “The Greater Threat Is Junk Science: An Open Letter to the AVMA.” http://www.voxfelina.com/2013/05/the-greater-threat-is-junk-science-an-open-letter-to-the-avma. Accessed April 30, 2014.