Chicago Sun-Times
Stray Casts will intelligently report and observe, hopefully with a touch of wit, on daily occurrences, reports and releases related to Chicago-area outdoors from bucks to bass to birds to bugs

Feral cats: $17 billion impact

| 26 Comments | No TrackBacks

It isn't often that birders and hunters are in lock step, but feral cats are a common ground: both groups spend enough time in the outdoors to know the destruction caused by wild cats and even free-ranging house cats.

cat bird

Gaëtan Priour took the photo above of a cat eating a bird.

A major study puts the impact at $17 billion in the United States.

When the announcement of the study came last week, I thought of the black cat that came stalking across the fields on opening day of deer season. And how a reader suggested I should have shot the ``timber cat.''

Cats are just bad outside. It shouldn't happen, even with cute little Fluffy in the backyard.

Here's the American Bird Conservancy with its word on the study:

New Report Puts Economic Impact of Feral Cat Predation on Birds at $17 Billion

(Washington, D.C., December 1, 2010) A new, peer-reviewed report titled, Feral Cats and Their Management from the University of Nebraska--Lincoln, has put the annual economic loss from feral cat predation on birds in the United States at $17 billion. The report analyzes existing research on management of the burgeoning feral cat population - over 60 million and counting -- in the United States, including the controversial practice of Trap, Neuter, Release (TNR).

"This report is a must read for any community or government official thinking about what to do about feral cats. It encapsulates the extensive research on this subject and draws conclusions based on that data. Not surprisingly, the report validates everything American Bird Conservancy has been saying about the feral cat issue for many years, namely TNR doesn't work in controlling feral cat populations," said Darin Schroeder, Vice President for Conservation Advocacy for American Bird Conservancy, the nation's leading bird conservation organization.

"Communities seeking a solution to their feral cat problems need to consider the science on the issue and the well being of animals impacted by feral cats as well as the cats themselves. These other animals - birds especially - don't deserve to die at the hands of a predator introduced into their environment by irresponsible pet owners. A humane decision-making process on this issue must also recognize that feral cats live short, miserable lives because of disease, other predators, severe weather and traffic hazards. Thus their life expectancy is about one third as long as owned cats," Schroeder added.

A key finding of the report was the statement by the authors that they do not recommend the TNR method to eliminate colonies of feral cats. In their extensive research, they were unable to find a single real-world example of TNR succeeding in eliminating a feral cat colony.

Some of the many findings of the report include:

· Feral cats are invasive and pose a threat to native fauna and public health.

· Three separate studies showed that most feral cats (62 to 80 percent) carry the parasite responsible for toxoplasmosis - a condition of special concern to pregnant women.

· Cats are responsible for the extinction of at least 33 species of birds.

· Feral cats kill an estimated 480 million birds in the U.S. each year (the study did not address the question of bird predation by owned cats. Studies suggest that there are 80 million owned cats in the U.S. and that 43 percent have access to the outdoors. Total cat predation on birds is likely around one billion birds per year, though some analyses suggest much higher figures.)

· Feeding feral cats encourages them to congregate which encourages the chances of diseases being transmitted.

· The supplemental feeding of feral cats should be prohibited.

· Cats kill far more native wildlife species than nuisance (invasive) species.

· Cats will kill wildlife no matter how well they are fed.

· One reference to TNR success claimed that one particular feral cat colony numbered 920 cats before TNR, and then 678 after. However, when migrations and births were factored in, the colony had actually increased in size -- to 983 cats.

· The life expectancy of a feral cat is 3-5 years as opposed to 15 years for owned cats.

The report can be viewed by going to the following website and then scrolling to report EC1781:

American Bird Conservancy ( conserves native birds and their habitats throughout the Americas by safeguarding the rarest species, conserving and restoring habitats, and reducing threats while building capacity of the bird conservation movement. ABC is a 501(c)(3) not-for-profit membership organization that is consistently awarded a top, four-star rating by the independent group, Charity Navigator.

No TrackBacks

TrackBack URL:


We should all be cautious about embracing recommendations from the University of Nebraska Lincoln Extension report which consist of flagrantly exaggerated conclusions lacking any scientific foundation. Further questions as to the validity of any claims made in this circular stem from the authors' unavoidable bias. Wildlife damage operators, “pest” specialists, and those who possess a natural resource background profit financially and/or recreationally from killing animals. Obviously, this creates a huge conflict with objectivity.

Unfortunately, the Sun-Times has decided to present this jibberish as a "major study." This is quite disturbing given that one of the authors openly admits that it was written for public consumption and was not submitted to science journals for publication. That’s probably wise given this document would never withstand the scrutiny of scientific review.

What is equally questionable about this document is the repeated concern for feeding feral cats and the resulting harm alleged when large numbers of animals congregate in any given location. This concern is quite ironic given that the authors apparently have no qualms whatsoever about the congregating and feeding of birds. In fact, despite the obvious likelihood of disease transmission that results from birds congregating around feeders and bird baths, the report actually encourages feeding birds …provided feeders are located “at least 10 feet from foliage or objects where cats can hide.”

There is no disputing that some cats kill birds. To my knowledge, however, there have been no determinative findings to support that cats are killing healthy birds. In fact, given the predator/prey relationship, the likelihood of cats preying upon healthy birds is quite slim.

As is the case with all predators other than humans, prey is targeted because it is sick, injured, young or very old. Cats are opportunistic by nature and may capitalize on birds that have been injured, ill or compromised. Cats that prey on the diseased, however, are providing an invaluable service to the remaining population by removing any threat of exposure to other birds.

Caution must also be taken with regard to the word euthanasia. Despite its political correctness, this term is often used to support methodologies that are neither quick nor painless. For instance, one of the authors of the report has publicly supported the injection of acetone/dimethyl-ketone (a/k/a nail polish remover) into the lung cavities of skunks (, casually referring to this brutal act as euthanasia.

A gunshot to the head is another questionable form of euthanasia given there is a high likelihood of error. Even for those individuals who possess proficient shooting skills, how can they be certain that the cat is going to hold still for the shot?

Body-gripping traps, notorious for their indiscriminate nature, have been shown to be incapable of killing animals instantly, despite the repeated assertions from trappers claiming otherwise, yet these too have been recommended by the authors of the report as an acceptable form of “euthanasia.”

Lethal control has proven repeatedly to be ineffective, cost-prohibitive and publicly unpalatable. The negative ramifications to this knee-jerk, ‘get-your-gun’ approach are not remedied simply because it is being recommended by an extension office.

Towns and municipalities across the country are embracing TNR ordinances, not because they are moved by the animal welfare aspect, but because this approach is effective, saves money and protects public health.

Please see the following website for additional information --


I have to take issue with your basic premise here: “Birders and hunters spend enough time in the outdoors to know the destruction caused by wild cats and even free-ranging house cats.” Really?

According to this line of reasoning, we should be consulting birders and hunters regarding West Nile Virus, carbon emissions, and climate change. After all, these are all “outdoorsy” issues, right? As a commuter, I see an awful lot of vehicles on the road. That doesn’t mean I know to design or repair them—only that I can recognize one as such when I see it.

Suggesting that birders and hunters, merely by being outdoors, know anything substantive about feral cats and their environmental impact is simply ridiculous. Experts on the subject will be the first to admit how complex such assessments can be.

Regarding the UNL paper, though, you’re doing readers a real disservice by referring it as if it were valid research. Though the motives of the report’s authors aren’t entirely clear to me, there’s no doubt whatsoever that they have little understanding of the key issues surrounding TNR—never mind the relevant science. Hildreth, Vantassel, and Hygnstrom misread, misinterpret, and/or misrepresent nearly every bit of research they reference. And, some of what they include isn’t valid research to begin with. (For a detailed critique of the UNL paper, please visit

Also, given the bizarre economics presented in the paper (granted, this is not the work of the UNL team), one could argue that hunters value an individual bird more than 500 times as much as a birdwatcher does. Suggesting, it seems, that dead birds are far more valuable than live birds! (Indeed, that could have been the story’s headline.)

The release of this paper adds nothing of value to the debate about feral cat management. The fact that it’s been embraced by the American Bird Conservancy, the Audubon Society, and others, says more about the questionable integrity of these organizations than it does the validity of the report.

As a journalist, you have an obligation to approach such stories with a healthy skepticism. Where’s the critical thinking? The opposing viewpoint(s)? It seems you’ve swallowed the whole thing in one gulp—what you’ve done here is little more than reprint the American Bird Conservancy's press release. Is it any wonder the newspaper business is struggling?

Peter J. Wolf
Reshaping the feral cat/TNR debate.

Reminds me of all the fishermen I've met over the years that hate various predator fish for eating their beloved whatevers.

Some hate muskies and pike, others hate gar, bowfin and catfish. They'll give you a million reasons why they need to be killed off.

Truth is, Laura is right. Predators keep prey populations healthy by eliminating the infirm. This keeps the gene pool of prey species in top shape.

It's also worth mentioning that humans cause way more extinctions than cats.

It is amazing the amount of debate a little pussy can stir up !

Jeff, educate yourself on the subject first, visit and read-up.

What a bunch of baloney. The hate mongerers at the Audobon society blame it all on one species that has its own horrors and is abandoned routinely. Where is the study on the other animals that eat birds....including the bigger birds? Just watch a bird migration and you will see the larger birds dipping down to catch and kill the smaller birds. What about those raccoons, foxes, and squirrels who eat fledglings or babies?

I'm a member of the Audobon society and I also participate in wild bird rehab, and I have to say that the information presented in the "research" and the analysis leading to the 17 billion figure is bogus. Yes, feral cats eat birds. Yes, TNR does not impact the populations of cats in the short-term. NO this does not mean that this results in billions of dollars in lost revenue... If this logic is valid then I can extrapolate that children result in billions of dollars in lost revenue due to the fact that I have observed a few in another state killing ants, thus they have a significant impact on ant populations, reducing the sales of insecticide and calls for exterminators.

Thank you Robert for presenting common sense from the "other side". TNR makes a difference in the long run, but not short-term. I've seen evidence of TNR working at a local college university campus in reducing the cat population.

Give it a break. There are enough birds on earth to feed everyone. That's why their there.

TNR does not work and is animal cruelty at it's best. Humane euthanasia is the only answer to our national feral cat epidemic. We have to start treating cats just like we treat dog colonies around in my area..........that's how we eradicated canine rabies in this country and that's how we will fix the feral cat problem. Let's pass some regulations similar to dog rules that apply to cats. Only then will we be free of these free roaming pests.

Redbud, please don't use the word "euthanasia" when you mean "kill", so I'm not sure how you would define animal cruelty when you want to kill cats. There is a feral cat problem, because people will spend more money on their dogs than on their cats. And yes there are feral dogs in places like East LA where certain breeds are used for dog-fighting, i.e. pitbulls, rotweillers. TNR does work, but it does not produce instant results. TNR also cost less than catch-n-kill, because these programs are all managed by volunteers on their time and dime. If you believe that catch-n-kill is the best solution to the feral cat problem, then I suggest you start your own volunteer program but I'm sure you'll be arrested for animal cruelty.

So I have read the pros and cons of this issue it is my feeling (after talking to responsible cat owners ) that all the stray casts' uh I mean, stray cats are spreading feline aids and killing all their beloved pets so maybe killing them is the right thing to do . Or we can listen to that one guy who thinks it is natural in that case release them on Galapagos island ......yeah that's it ! ! !

17 reasons the economic impact of the domestic cat is not $17 billion:

1) "Feral Cats and Their Management" calculates the cost incorrectly
2) It is based on the work of David Pimentel whose work is flawed and the cost as published in his 2005 update was simply wrong

The premise of the valuation is flawed:

3) There is no strong research to support the viewpoint that cats are a serious threat to wildlife nationwide:
4) Cats kill non-native species;
5) Bird predation by cats may be primarily compensatory;

Pimentel's (and thus the UNL report authors) assumptions are based on poor research that overestimates the impact because:

6) cats are opportunistic feeders
7) not all cats hunt birds
8) 65% of cats do NOT roam;
9) cats kept indoors cannot hunt
10) not all free-roaming pet cats hunt (anything)
11) feral cat population estimates are poor
12) feral cats hunt fewer birds than house cats (dependent upon prey availability)
13) The 2000 and 2005 Pimentel reports use aggressive bird depredation rate assumptions
14) Proper numbers to scale-up study data to population-level estimates must be used

The $30 per bird valuation is subjective and thus not a reasonable estimate of financial loss:

15) why are dead birds more valuable than dead fish?
16) why are dead birds more valuable than dead cats (or dogs)
17) are wild birds 12 times more valuable than chickens or three times more valuable than turkeys?

American Bird Conservancy knows full well that there is no $17 billion dollar economic impact from cat predation on birds and they are doing wildlife a disservice by allowing themselves to devolve into a propaganda organization. I am an avid bird watcher and my first bird guide was published by ABC. They know that bird watchers don't spend money on a per-bird basis any more than movie goers pay the minute or baseball fans pay by the number of pitches thrown. We spend money for the incredible experience of seeing diversity of species and particularly to see "target" species, such as an Elegant Trogon in Arizona or an Arctic Warbler in Alaska. For cat predation to have an economic impact they'd have to wipe out those target species or at least diminish their number to the extent that bird watchers no longer wanted to travel to those locations. There is no evidence that that is the case.

The logic behind the $30 value of each individual bird is also anything but new. It was published in 1992 in a paper on pesticide use based larger on 1985 survey data. I have yet to find a single scientist, including the Nebraska authors or the Cornell authors of the original estimate, who can explain how the $30 figure is arrived at, even if the underlying data was sound.

Feral cats are not native and they are not good for wildlife. However, until we start having rational discussions on how to best reduce their number in various settings, we aren't going to make a dent in this problem. ABC for many years advised communities to build sanctuaries to address their feral cat problems and they used Chico, CA as their model. Of course, the Chico sanctuary quickly filled up and Chico found itself addressing a feral cat problem all over again. ABC just really has no credibility on the issue, unfortunately.

Walter Lamb

For the birds sake. That's all I ask. I see it every yr., the dwindling of the # of birds in my garden. I find feathers every 1 or 2 days after an attack. I see the cats around all the time. For me, I would vote to delete as many cats as possible. I hardly see a beautiful songbird anymore. There is the tragedy. It just seems like the birds are over looked and forgotten. What a terrible species we are to allow the things we let happen to wildlife. I know we can't control all the things animals do to each other. But I do know we could be doing a whole lot better than what we are..... I love birds in the garden

Calling all humans, calling all humans kill all the cats a fast as you can!!!

Ironic it is indeed
That humans should feel the need
To tag other species destructive
The logic is just not deductive

Unparallelled in earthly destruction
The naked ape
Needs no introduction

What the heck is their malfunction?

There is now a peer-reviewed analysis specifically refuting the absurd claim that cat predation of birds causes $17 billion in economic damage a year. There was never any science behind that claim and the wildlife conservation community and the media should now take a step back and ask how this claim went unchallenged for many years.

The point here isn't that birds aren't valuable or that we should not try to reduce the number of outdoor cats and their impact of wildlife. The point is that it is never acceptable for scientists to use science as a tool to push an ideological agenda. I hope the author will have the journalistic integrity to follow up on this story. That would include asking the American Bird Conservancy why they so quickly promoted this obviously faulty "study."

Walter Lamb

Hi Dale,

The problem is that these studies come out and get instant media coverage and it can take months or years to get responses published. Those of us trying to instill some accountability into the process will always be trailing behind. The Loss et al study is highly dubious given current knowledge about bird populations and mortality, but by the time a response gets written and published, the Loss study will be long forgotten and there will be some new study getting the media attention.

What I would ask is that you revisit the topic with a new article, given that the headline of the first article has been discredited. The best way to reduce the number of cats in the environment is for us to focus on sound, objective science when forming policy. That is not the case currently.

It is worth noting that the same organization hosting a copy of the Loss et al study is still also hosting a press release about the bogus $17 billion dollar claim.

ABC published my the first bird field guide I ever owned, so it has been disappointing to see them favor PR spin over scientific objectivity on this issue.

Walter Lamb

Dale - Correcting an errant headline isn't hijacking anything. When an individual journalist decides which scientific information is allowed into the conversation it creates an atmosphere that is not conducive to science-based policy. We don't want the Fox News vs. MSNBC News paradigm to creep into our scientific discourse.


The problem is when people with an agenda are making that distinction. Your headline is based on a discredited study. No need to discuss this further as you have made clear that you don't intend to do a follow up.

Another outdoors issue that you may be more eager to cover, and which desperately needs more coverage is the attempt by the Annenberg Foundation to construct a dog and cat center in a protected ecological reserve here in Los Angeles. This would require the California Fish and Game Commission to rewrite the regulations governing this reserve, which would set a terrible nationwide precedent whereby cash-strapped government agencies would be tempted to trade public resources for cash, even if such an exchange caused them to compromise their publicly mandated missions.

Just search on Ballona and Annenberg for more info.

Walter, a 'commentary' is not a peer-reviewed response. Please try again.

Leave a comment

About this Entry

This page contains a single entry by Dale Bowman published on December 6, 2010 5:57 AM.

Illinois deer hunting: My season was the previous entry in this blog.

Northerly Island: Raves is the next entry in this blog.

Find recent content on the main index or look in the archives to find all content.