Bird Conservationists – What’s Wrong With This Picture?

Bird conservationists are perhaps the most effective opponents of Trap-Neuter-Return (TNR) programs for feral cats. The conservationists argue that scientific studies show that cats kill huge numbers of birds, and that therefore cats must be removed from the environment to protect birds. TNR supporters argue that estimates of cat predation are overblown and, in any event, TNR is the only successful way to manage cat populations. Although most of the bird conservationists won’t come right out and say it, what they all seem to want is to round up and kill all homeless and feral cats and to force people who own pet cats to confine them indoors. Current estimates are that there are at least 80 million pet cats and tens of millions of feral cats in the United States.

Recently I began studying the science of the cat-predation issue. Because the science is controversial I expected to find what I usually see in scientific controversies, which is evidence on both sides of the issue. What I actually found ran completely counter to my expectations, and shocked me. In journal article after journal article, and book after book, I found cat-predation studies that were flawed by small sample size, samples that were not shown to be typical, unjustified generalizations, a failure to account for confounding factors, and a tendency to assume that predation of individual birds necessarily resulted in damage to bird populations at the species level.

After perusing the studies and writings of many bird conservationists I came to the conclusion that they were unable to see the data clearly. As someone who is a great believer in the scientific method, and who respects scientists, I don’t say this lightly. I’m used to scientists being the people we can rely on to look at issues dispassionately and give us objective conclusions based on data. I had always assumed that there must be some “there” there in the cat-predation controversy, simply because there are reputable scientists who strongly believe that cats harm bird populations. So it was a very rude awakening when I began to study the data and saw how unconvincing the evidence against cats in general, and TNR in particular, actually was.

I don’t have the space in this blog post to dissect the weaknesses of all the scientific studies, and others have done that anyway (see Peter Wolf’s “Vox Felina” blog, linked in the left sidebar). The point that I want to make here is somewhat different, and that is that the bird conservationists, regardless of the validity or lack of validity in the studies they publish in journals, exhibit contradictions in their own writings about cats that are clear evidence of their lack of objectivity on this issue. As a case in point, we need only look at John M. Marzluff’s book “Welcome to Subirdia.” Marzluff is a respected professor of Wildlife Science at the University of Washington. I thought “Welcome to Subirdia” was a delightful and important book, and I would recommend it to anyone. The thesis of the book is that green suburbs are unexpectedly wonderful habitat for birds, and nurture a wide variety of bird species.

But in spite of Marzluff’s happy message of birds doing extremely well in the suburbs, his book is marred with inexplicable internal contradictions when he talks about cats. To start with, we know that there are probably as many free-roaming cats in the suburbs as there are anyplace on earth, except possibly for some neglected urban areas. Given this, how would you complete the following syllogism:

In the suburbs we find an abundance of bird species, cats are also abundant in the suburbs, so —

  • Choice A:  cats do not harm and may even help bird species, or
  • Choice B:  we need to confine or kill all the cats in order to save the birds.

It seems to me that any rational scientist would pick “A” to complete the syllogism, but Marzluff pretty clearly agrees with “B.” In fact, on page 85 of the book he says that cat predation on birds is “horrifying.” On page 173 he says that the “most uniformly serious” peril to birds and other animals in the city is the free-roaming domestic cat.

But wait, Dr. Marzluff, wait! Didn’t you just explain to us in a very well-written and convincing way that green suburbs are among the best habitats for birds? Didn’t you tell us on pages 15-16 that you found more bird diversity in Central Park in New York City than you did in Yellowstone? And aren’t there a whole lot more domestic cats in the suburbs than in Yellowstone?– my head is hurting.

There’s more. One of Marzluff’s students did an experiment to examine causes of mortality of fledgling birds (pages 91-93). Unlike many bird-mortality studies, this one seems to have been designed and carried out fairly well. It was perhaps a bit small, with a sample size of 122 fledglings, but that number is large enough to be at least indicative, although not conclusive. The best thing about the study design was that the birds were radio-tracked. This allowed Marzluff and his student to determine the location and movements of the fledglings for the approximately three to nine weeks that the batteries lasted. The period of a few days when a bird is learning to fly is one of the most vulnerable time periods of its life. If cats really do account for 10% of deaths of all birds in the United States (as Marzluff maintains, see pages 85 and 188) then we would expect cats to kill a substantially higher percentage of fledglings – 20%, 30%, perhaps even upwards of 50%.

The results were extremely interesting. What the study actually showed was that cats were “implicated” in the death of only one fledgling. And Marzluff admits that it was not clear that the one fledgling was actually killed by a cat, and it could have been killed by another mammal or even another bird. Now, one would think that a good scientist like Marzluff, on receiving this data from an experiment that he and his student performed themselves, might scratch his head and say — maybe cats really aren’t as bad as we thought. Or at least — this is interesting, we need to study this in more depth. But that isn’t what Marzluff said. Instead, he dismissed the “rarity” of cat predation in the study (by which I think he means the “non-existence” or “near non-existence” of cat predation in the study) by opining that it was due to the presence of coyotes in the area.

If coyotes were prevalent enough in the area of the study to chase away or kill off all the cats, then one would think that coyotes would have killed some of those fledglings themselves. Perhaps they did. But Marzluff believes that coyote predation is good for bird populations (page 199). According to Marzluff, cats kill birds (bad), but coyotes “cull” their prey, which is good because it is nature’s way and they only kill the injured, weak and overly abundant. Predator coyotes are wonderful, while the slightly smaller predator cat is horrible. Okay, now my head is going to explode.

I really don’t mean to pick on Marzluff. Others are worse than him. I’m discussing “Welcome to Subirdia” in this blog post because it happens to offer a particularly clear example of the way the cat issue seems to twist the thinking of even good scientists. So, back to the question – why does this happen? Why are bird conservationists, who make their careers by being logical and fair and sticking to the data, seemingly so blinded by their anti-cat emotions that they cannot see the data clearly?

If I were going to study the issue I would start with two hypotheses. One is the hypothesis that bird conservationists have an animus toward cats because they view cats as an “invasive” species. As I discussed in a blog post last month, there is recent thinking that the whole “invasive species” thing is really just mother nature’s reaction to the massive changes that humans have made in the environment. My second hypothesis is that there is a prejudice against cats due to the perception that they are cruel killers because they sometimes seem to torment their prey or play with it before killing it. Scientists ought to know, if anyone does, that species do not survive and thrive the way cats have if they waste energy. Therefore, there is probably a reason for the way cats sometimes make their kills. One obvious reason would be that they are learning or improving hunting skills. Cats are not very big, and in some habitats they need to kill prey animals, such as rats, that are almost as big as they are. A cat does not have the luxury of the size and weight of a coyote or wolf. Since cats cannot always overpower their prey by brute force, they have to fight with skill and tactics – which takes practice.

Whatever the reason or reasons for the animus that bird conservationists have toward cats, it has consequences. We need look no further than Washington, DC, where a battle is now being waged between TNR advocates and conservationists who want to round up cats and take them to shelters (where the feral ones would be killed) and force owners of pet cats to keep them indoors on pain of death (death to the cats, not the owners, although sometimes one wonders).

This is already a long blog post and I don’t have space here to get very deeply into the related question of why bird conservationists reject TNR. There is one glaring logical contradiction here, too, though, that I want to touch on. Even if we all were to agree that cats are damaging bird populations at the species level (an idea that Welcome to Subirdia very neatly refutes), one would think that bird conservationists and cat advocates could nevertheless agree on TNR, because TNR not only reduces the number of cats, it also reduces the need of cats to hunt, since colony caregivers feed the cats. Moreover, probably 99% of the labor and supplies that are expended on TNR and colony care are donated by volunteers, without costing taxpayers or businesses a dime. Catch-and-kill methods have to be repeated every two years at least, they are expensive, and the advocates of the catch-and-kill method have not figured out how to keep people from sabotaging it by very naturally doing everything they can short of going to jail to save their neighborhood cats.

The bird-conservationist ranks do not seem to contain enough people who are willing to catch and kill cats all over the country with volunteer labor and supplies, so the bird conservationists expect governments to pick up the tab for their cat-killing program. This adds insult to injury, because it means that citizens who pay taxes are forced to pay for killing cats, when in fact the majority do not approve of the wholesale slaughter of cats. This is not a winning scenario for the conservationists. It can only lead to long, drawn-out, pitched battles that the conservationists will ultimately lose, because they are not only in the wrong, they are in the minority. One would think that the bird conservationists would realize that TNR is the best solution that is actually possible to achieve, even if it is not their favorite solution. Instead, they continue to oppose TNR, holding out for the unrealistic option of somehow finding, catching and killing every cat that wanders outdoors, and forcing people who disagree with them to pay for it.

We can’t send all the bird conservationists back to science school, so all we can do is hope that eventually rationality will prevail. In the meantime, pick up a copy of Welcome to Subirdia. I’m sure you’ll love it. It’s a very convincing argument that birds do better with cats around.


  1. I’ve had and been around cats my whole life. I managed a feral colony for a few years. Cats have taught me just about everything I know … about birds. I was a bird rescuer for awhile. Where I lived it was overrun with mynah birds brought over by the whalers the same way the cats were brought here yet for very different reasons … the mynahs were entertainment, the cats had a very important job to do. Keep the rat population down. So now you have a mynah overpopulation … arguably some of the most disgusting birds on the planet with their loud, raucous banter and ‘gang bang’ technique of culling their own families. The mynahs are so disgusting the cats don’t even bother with them. Too bad because the mynahs are flying rats. Even if the cats can catch them (which most often they can’t) they can’t put at dent in their numbers. Doves they can catch and occasionally an adorable little white eye however even if they got one per day (which they don’t) they could never put a dent in the population of ANY bird species unless it was a protected species. It just ain’t that easy to catch a bird. They can fly. I have a cardinal that eats my cats food out of their dish and has risked his feathers for months with four cats. One of my cats came close … he lost a feather that day … but he came back. He figured it was worth the risk. Smart bird. Much smarter than the cat. Cats don’t compete with the bird’s food supply …. other birds do that. Balance is what is needed and nature is pretty darn good at figuring it all out … if we pesky humans would just get out of the way …

    • Your activities don’t prepare you to objective and measure outcomes, however. Merely “doing it for X years” doesn’t mean you have been applying best practices in the field, standard practices, or even the most appropriate ones. It merely means you engaged in an activity which in which you seemingly failed to see any appreciable reduction in population but are unwilling to acknowledge constitutes failure. So, essentially? You learned…nothing, apparently.

    • Bonnie, Your understanding of ecology and predator prey relationships is monumentally self centered, to include only what you believe…cats are good….all else is bad. The cats are introduced predators and not at all a part of the wildlife or natural predator prey relationships. Why do you defend them when they do such damage? Can you only identify with cats, the introduced non-native predator that spreads infectious diseases like Toxoplasma gondii to the humans and the other wildlife? Cats are not part of any natural balance I’ve ever studies, as they are a domesticated species and NOT “natural” at all.

    • That is a ridiculous argument, both the mynah and cats are invasive in some areas, depending on the area. One doesn’t prove that the other is harmless. One invasive species that is damaging doesn’t prove that all the others are okay or not okay too. It depends on the damage and destruction to the ecology. I’m fine with wiping pythons out in Florida too, that doesn’t I think the feral cats are fine or not fine. It depends on the destruction.

  2. (Standing ovation) FINALLY! Finally, someone has enlightened/educated themselves on the subject BEFORE writing an article on it. Far too many do the opposite.

    STOP blaming cats for things HUMANS do!

        • Let’s assume for the sake of argument that you are right that invasive species are the devil’s spawn. In the case of feral cats, what is the specific plan that you would like to see enacted, how would you pay for it, and what evidence do you have that it would be effective?

          • Hunt them to extinction. Make unrestrained outdoor cats illegal, as is the case with dogs in most municipalities. Establish bounties. Like Australia is attempting. Their stated goal of 10% eradication. Not nearly enough. Cats breed faster than that.

            Historical examples of successful eradication campaigns involving bounties: Timber wolves–nearly eradicated in the lower 48 states after the US govt. established a bounty on them in 1880. Pretty much gone by 1887 (I live in Alaska–we still have them here). And that was at a time when people were far less numerous, urban areas far less extensive, and firearms and other gear far less sophisticated.

            And your childish snipe about invasive species being ‘devil’s spawn’ merely demonstrates your inability to discuss the issue in those terms. Perhaps you’re well-read enough to realize that with respect to invasive species the facts do not support you. Or perhaps you simply prefer childish ‘comebacks’.

          • OK, you’ve laid out your draconian plan, with a ton of ill-concealed emotion behind it. Exactly how are you going to accomplish this? It ain’t the 1880s anymore, and the citizenry doesn’t take kindly these days to extermination campaigns. The citizenry may be right or they may be wrong, but if you cannot put your plan into effect, what good is it? TNR, on the other hand, is very popular and we have an army of people who are doing it. Perhaps you ought to hope that you are wrong about TNR, since your plan doesn’t have a prayer in the real world.

  3. Wow, what an impressive compilation of misinformation and misconceptions. One true statement: you cannot “can’t send all the bird conservationists back to science school,” because many of us have gone already. The bird conservation community includes people with Ph.D.’s and other graduate degrees in ecology, conservation biology, and every other relevant field. The community supporting TNR includes almost no one with any qualifications from any relevant scientific field, as exemplified by TNR’s reigning supporter Peter Wolf (Vox Felina), an engineer with absolutely no training or background in ecology or conservation, and a science-denying hack not substantially different from the “scientists” cited in support of vaccination refusal and creation science. I can supply any number of citations to correct your misunderstandings – as to why Marzluff’s work does not support TNR at all, why coyotes are better for birds than cats, and much more – but nearly every TNR supporter with whom I’ve conversed has been too blinded by their emotional attachment to feral cats to accept scientific reality….

    • I’m quite ready to listen to anything you have to say about why no confirmed cat kills and only one possible cat kill out of 122 fledglings is evidence supporting cat predation, or why coyotes killing birds is good but cats killing birds is bad, or how the suburbs could possibly be a great place for bird species diversity with all those cats around. And while you’re at it, please explain how, exactly, your plan for cats will work better than TNR.

      • I’ll be very happy to explain what I can, as time allows. We’ll see if I can get to it all. I’ll start with your coyote question, as it’s the simplest one and easiest to explain. Cats and coyotes exhibit a syndrome that ecologists call “mesopredator release.” Coyotes in urban and suburban habitats are the top predator; cats are mesopredators, along with raccoons, skunks, and various other critters of similar size and behavior. Feral cats, and any other mesopredators present, can reach very high densities in the absence of the top predator. When coyotes inhabit an area, densities of feral cats and other mesopredators are much lower. So while a coyote might kill an occasional bird, for every bird the coyote kills, it saves the lives of dozens more by killing or chasing away feral cats etc. This is, indeed, excellent for birds; published studies have shown that bird abundance, and better yet bird species diversity, are higher in habitat patches where coyotes are present, than in patches which lack coyotes and have more cats. Mesopredator release is a general phenomenon which has been demonstrated in other top predator-mesopredator-prey systems, not just coyote-cat-bird, and in most of them the removal of the top predator causes a cascade leading to localized extinction of certain prey species.

        The fact that coyotes are preferable to cats goes beyond mesopredator release, though. The problems get worse because, while very few people are stupid enough to intentionally feed wild coyotes, or wild mesopredators like skunks or opossums, great hordes of people are stupid enough to feed feral cats, or to let their pet cats roam freely outdoors. In nature, if predators deplete their prey supply, the depleted prey leads to predator starvation, so predator populations decline, allowing prey populations a chance to recover. Bad news for starving coyotes and other wild predators, but good news for the birds. However, if people are stupid enough to feed feral cats or allow pets to roam outside, those cats become a starvation-proof predator population. No matter how many prey they kill or how rare the prey get, the cat population never decreases, because wild prey are not their sole food source, they also get fed by people. So the cat populations maintain or increase for decades, and bird and other wildlife populations never get any relief from predation but just keep declining indefinitely.

        I have to log off now; it’s late here and I have my own three cats to care for, plus two children, a dog, and more. We’ll see if I have time to come back and answer your other questions later.

        • Thanks for your reply. By your own admission, though, what you said about coyotes and cats applies in “urban and suburban habitats.” So you are not really talking about preserving natural habitat; instead, you are talking about tweaking a highly unnatural habitat so that it looks more like you would like it to look. People like pet cats, though, just as they like cars and manicured grass and impermeable surfaces like roads and driveways. Cats are only one part, and actually a pretty small part, of the profound disruptions to the environment occasioned by people who have built “urban and suburban habitats.” You are not going to succeed in getting people to give up cats any more than you can succeed in getting them to give up roads and driveways. Fortunately, TNR has been shown to be effective at limiting cat numbers in restricted territories, and TNR is enthusiastically embraced by people. So, you can keep trying to get people to give up their cats, or perhaps you could make more progress by helping to perfect how we do TNR in the highly unnatural urban and suburban environment.

          One other point is that simply removing cats from the urban and suburban landscape might have some unintended consequences. Just as coyotes can squeeze out cats, cats can squeeze out rats and mice. If we were somehow able to remove cats from the “urban and suburban habitats,” the trash, empty buildings, and other sources of food and shelter that feral cats use would still be there. Imagine the reaction if you persuaded a city to adopt a program that exterminated all the cats, only to have a huge increase in the number of rats. Conversely, if we got rid of the trash and the empty buildings while managing cat colonies, we could go a long way to solving the problem at its roots.

      • Here’s the documentation you requested. Please read it carefully. It’s supported by experts from accredited institutions conducing peer-reviewed science.

        A recommendation to you: please take at least one biology course before replying. This will alleviate the necessity to explain basic biological terminology to you such as carrying capacity, invasive, domesticated species (selectively bred), zoonotic diseases, and the scientific method in general.

        • Thanks Eva, but I have taken lots of biology courses, enough in fact to earn a degree in zoology. As to the links you have provided above, there has been lots of back-and-forth and analysis of those studies. There is no easy way to accurately measure feral cat predation, due to the nature of the predation and the fact that cat predation varies a lot by habitat and from cat to cat. Furthermore, the question of whether cats are bad for birds at the population level involves a lot more than simple predation numbers.

      • If you cannot see the difference in predation by indigenous animals and that by feral animals, I can see why you do not understand the rest of the TNR opposition. All feral animals in all states and provinces have been found to have grave ecological impacts.
        The southern US and indeed all states and provinces, have issued capture/kill orders for all feral animals except for feral domestic cats. It is not because they enhance the environment. It is not because we do not have an effective method of eliminating them. It is because of a lack of political will from the ‘Bambi Effect’. It is quite sad that conservation laws are written by people who need to popular to retain their positions and not by people who actually work with wildlife. Feral animals should not elevated to some imaginary status or category. Cherry picking which ferals should die and which shouldn’t removes you from the entire debate.
        We either remove them all or we let it all go and see what happens. We do not TNR pythons, hogs or any other feral, and it should not be done with cats.
        And yes, I am a real wildlife biologist and I do believe it is important to set aside emotions when dealing with such a massive problem as feral animals.

        • I’m not sure why this is, but bird conservationists seem unable to hold the concept in their minds that proponents of TNR are not for it because of what you so condescendingly call the “Bambi effect,” but because TNR at least has a chance to reduce the number of free-roaming cats, whereas the catch-and-kill method has no chance. People like cats. They will hide cats from you, so you will never be able to find and kill them all. They will protest loud and long about their tax dollars being spent to kill cats. Those same people, by contrast, will happily spend their own time and money doing TNR.

          You don’t get to decide who is “in the debate” and who isn’t. Ultimately, public policy is set by citizens. You may feel that wildlife biologists should be able to direct everything that happens in the outdoors without any interference from the rest of us plebeians, but that’s an arrogant and self-defeating attitude.

          I suspect that the ultimate solution for reducing the number of free-roaming cats will be a combination of dealing with trash and abandoned structures in and around human habitation, TNR, and continued availability of free sterilization for owned cats. We will accomplish that with or without you, but if the bird conservationists would join us in getting these things done instead of blocking progress by opposing the only programs that have a chance of working, it would go faster.

          • And I quote. “Trap-Neuter-Release programs are intended to reduce cat populations by surgically sterilizing as many feral cats as can be caught. These cats are then released back into the environment. In some instances, the groups attempt to “manage” these feral populations by feeding cats in a specific area, the intention being to keep them from preying on other animals.

            This solution on its face has a certain moral palatability and logical origin. If all feral cats are prevented from reproducing, then eventually the population will be reduced to zero, and this can be accomplished without killing a cat. But the flaws in this thinking should be apparent. Not all cats can be captured, and these continue to reproduce. New individuals can enter the TNR area at will, and they will reproduce. And surgical sterilization does nothing to prevent continued predation on native wildlife. TNR can neither eliminate feral cats, nor reduce predation, and does not address illness or disease, facts supported by actual scientific study.

            Proponents of TNR ignore these facts. They downplay or deny outright the problems with rabies and other diseases. They counter that feral cats are a natural part of the ecosystem and play an important role in the biologic control of pest species, that the estimation of wildlife killed by cats is grossly exaggerated, and that conservation groups have more important things to worry about. They have provided no studies that refute the numbers of wildlife killed. The studies that they do refer to regarding the effectiveness of TNR are of limited scope, and often contradictory in their findings. All of these studies openly admit that TNR will not be effective at eliminating feral cat populations.

            What is not in dispute is that domestic cats are an invasive species, with a population of 60-70 million in North America. Derived from the desert-dwelling wild felines of northern Africa, and brought to this continent by European settlers, cats are exceptionally well adapted to a predatory lifestyle, having keen eyesight, acute hearing and sense of smell, incredible strength and speed, lethal weaponry, and an incredible rate of reproduction. Cats are beautiful, efficient, and almost-perfect predators. And they are an alien species, altering the landscape, and causing- environmental, agricultural, and economic harm. There is no other small cat native to North America similar to Felis sylvestris, and thus
            they have a huge and disproportionately damaging effect on wildlife.

            Cats have their own biology, ecology, and ethnology, and their behaviors directly impact the biome. There are 60-70 million feral cats in the North America. Feral cats draw their sustenance almost entirely from wildlife that they catch and kill. A cat will eat as often as possible, and must eat several times a week (at least) to survive. These are facts, undisputed by both sides. One shouldn’t need to use statistics or years-long research to see how quickly the numbers of dead prey add up.

            Clearly, given the stated facts, feral cats must be completely removed from the environment, and by that I mean active extermination. From an ethical perspective, this may sound like a difficult thing to do, and I understand the visceral response concerning the outright extermination of an individual life. But only the complete elimination of feral cats will provide the solutions that both conservationists and feline advocates want. Disease, health problems, public safety, and environmental concerns are all addressed successfully by eliminating the feral feline population. I have considered all other possible solutions from the perspective of both a veterinarian and a conservationist, and they are either impractical or impossible.” Brian Monk, DMV.

          • Actually, the 60-70 million figure is not only “in dispute,” it is nothing more than a guess. And there has been quite a bit of evidence, starting as long ago as the 1970s with Roger Tabor in England, that cat colonies deter new cats from entering their territories. And you do not explain how cats are to be “completely removed from the environment.”

          • You may think the numbers are ‘in dispute” but the impact feral cats have on the environment is certainly not in dispute.

            Trap-Euthanize, or, just like we do for other feral animals, shot them on site. This is obviously the most cost effective measure.

            Not to mention, Trap-Neuter-Re-Abandon is a direct violation of abandonment laws in many states. “A person commits the crime of animal abandonment if the person intentionally, knowingly, recklessly or with criminal negligence leaves a domestic animal at a location without providing for the animal’s continued care.”

  4. “OK, you’ve laid out your draconian plan, with a ton of ill-concealed emotion behind it.”

    Draconian? Unavoidable. And at least you dump your ton of emotion out where nobody can miss it. You are to be commended for that, I suppose…

    “Exactly how are you going to accomplish this? It ain’t the 1880s anymore, and the citizenry doesn’t take kindly these days to extermination campaigns.”

    Yeah, my son and two of my grandchildren live in Australia–I go there pretty much every year for extensive visits. And there are maudlin, ill-informed individuals who whine about ‘poor kitties’ like you do. The responsible agencies are ignoring their, and Bridgette Bardot’s, objections basically because they have no choice.

    “The citizenry may be right or they may be wrong, but if you cannot put your plan into effect, what good is it?”

    Remains to be seen. The Australians are trying to do so. You assume that you and your ilk will remain the dominant voice in this controversy. That’s starting to change–PetCo funding notwithstanding.

    “TNR, on the other hand, is very popular and we have an army of people who are doing it. Perhaps you ought to hope that you are wrong about TNR, since your plan doesn’t have a prayer in the real world.”

    Fair enough–show me a real-world example of TNR actually WORKING, then let’s talk about it. And I’m not talking feral cat-lobbyist ‘testimonials’. Peer-reviewed scientific studies.

    PS: I ask that you not waste my time with the three studies in which J. K. Levy participated. They don’t support you. She’s already admitted that TNR achieves minimal population-level effects.

  5. “As someone who is a great believer in the scientific method, and who respects scientists…”
    So where is the science that shows TNR is effective?
    “… one would think that bird conservationists and cat advocates could nevertheless agree on TNR, because TNR not only reduces the number of cats, it also reduces the need of cats to hunt, since colony caregivers feed the cats.”
    Now my head is going to explode…but I digress, again, where is the science that shows TNR reduces cat numbers?

    • There are lots of examples of TNR reducing colony size. I don’t think there is any experimental model that could determine whether or not TNR reduces the number of cats in the US as a whole, because we don’t even know how many ferals cats there are in the US as a whole. By the same token, though, there is no evidence that catch-and-kill will reduce feral cat numbers in the US either. It boils down to the fact that TNR is a practical solution, because people will support it and it is largely paid for and carried out by volunteers. Catch-and-kill is not practical because people will not support it and no one will do it unless they are paid. Try getting the taxpayers to stand for that. If you are a betting man you would be well-advised to bet on TNR, because it is the only horse in the race.

      • “There are lots of examples of TNR reducing colony size.”

        Example? It’s no sufficient merely to assert something–one must demonstrate it. By other means than through quoting ‘testimonials’ from fellow feral cat-lobbyists.

        “I don’t think there is any experimental model that could determine whether or not TNR reduces the number of cats in the US as a whole, because we don’t even know how many ferals cats there are in the US as a whole.”

        Sure there is. Do a rate comparison: Feral cat annual population increase (from whatever population estimate you accept) vs TNR rate based on number of feral cats TNR’d annually. If you don’t have that data it’s because your cat-lobbyist friends aren’t keeping it. But I think the numbers are available–I’m finding some as part of a work-in-progress on this very question.

        “By the same token, though, there is no evidence that catch-and-kill will reduce feral cat numbers in the US either.”

        I gave you an historical example. I can provide more–some even more ‘extreme’. So far your only objection to the one I gave is that such a course wouldn’t be publicly popular. At one time not that long ago anti-smoking campaigns weren’t publicly popular. That’s changed. Despite considerable corporate opposition.

        And of course you and your ilk are doing your damnedest to float all the pro-TNR propaganda PetCo and PetSmart money can buy. Nonetheless, there are other voices in opposition to yours, and when the situation becomes desperate enough maudlin public sentiment will be overcome and rational policies will be implemented. We see this happening in Australia as we speak. It’s a beginning, and if done correctly will almost certainly prove to be a damned sight more effective than TNR–but then, that’s not saying much, is it?

        “It boils down to the fact that TNR is a practical solution, because people will support it and it is largely paid for and carried out by volunteers.”

        For the words ‘practical’ and ‘solution’ to apply, one must have a program that works. You don’t.

      • Please list one from a credible source.

        A credible source would be an scientific institution, such as a research organization, institution of higher learning, or governmental research agency.

        A non-credible source is a organization’s website with unsupported testimonials, or claims made that a behavior is “effective,” without any testing, measurement, or outcomes which can be documented and/or subjected to scrutiny.

        • I’m not aware of any research organization, institution of higher learning, or government research agency in the United States that has done a formal study on whether TNR in a limited area reduces colony size. There are several such studies that have been done by veterinarians, some of whom are associated with universities. Not sure if that meets your criteria or not.

  6. Joshua Rose’s comment is rather typical, I’m afraid, of what I’ve come across. Lots of arrogance and broad generalizations.

    At the risk of hijacking the conversation, a couple brief comments… While it’s true that I have no formal training in biology, zoology, etc., I think my training and experience as an engineer is hardly irrelevant. For one, it’s taught me to be skeptical of extraordinary claims (e.g., cats in the U.S. alone kill up to 4.0 billion birds each year). I also read the work I cite, a rarity, apparently in the conservation community (or at least among those engaged in the witch-hunt against outdoor cats).

    I’m not kidding, either. I’m astonished at how many misrepresentations (intentional or not) I see repeated time and time again. Had the author in question read the work, s/he never would have cited it in the way s/he did.

    And there are the statistical/analytical errors—again, you don’t need to have a PhD in biology to pick this stuff out. That 2013 paper claiming cats kill up to 4.0 billion birds/year? The authors’ model used a uniform distribution for prey killed/cat. No study—including those cited by the paper’s authors!—has ever documented such a distribution. This error alone has enormous consequences on the eventual “estimates” the authors generated.

    As anybody familiar with my blog can attest, I could go on and on. What I find truly puzzling, is this: if I’m so wrong about these things, how come nobody’s set me straight. Somebody explain to me, for example—just as a start—(1) why it’s acceptable to use a uniform distribution in the context I describe above, and/or (2) how doing so is inconsequential to the predation “estimates.”

    Again, if I’m so off-the-mark, it shouldn’t be difficult to make the case.

    • Nice strawman. The Smithsonian paper said up to 3.7 billion birds a year are killed by cats. That is the top end of a range they provided. By citing only the top estimate you betray your lie. That number is only a worst case scenario based on the research available but the low end of the range in that peer-reviewed paper is 1.4 billion birds. Still a completely unacceptable number that makes cats the top cause of direct bird mortality in the country.

    • Perhaps a better question would be “Why has no actual scientist confirmed your conjectures”? Surely many scientists have seen your blog and read your theories, yet none have stepped forward and said, “Hey, he’s right”. Not one. You don’t suppose they’ve all dismissed it because they see it for what it is, do you?

      • Actually, there are scientists who have presented studies showing that TNR decreases colony size — i.e., showing that in-migration does not make up for the reduced reproductive rate. Wildlife biologists seem to discount those studies because most of them were performed by scientists who are not wildlife biologists. But the studies done by wildlife biologists on cat predation are, I’m sorry, lousy. One of the reasons that the “scientific” papers put out by wildlife biologists have been so bad is that they are trying to cobble together conclusions from inadequate data. And presumably the reason that the data is inadequate is that the rest of society (i.e. people other than wildlife biologists) just doesn’t see feral cats as a question of burning importance, and therefore feral cats are not attracting a lot of research dollars.

    • You’ve submitted an awful lot of comments to the blog, and I’ve posted almost all of them. The ones I have not posted are ones that are repetitive and do not contribute to the conversation. I allow comments, but it is not fair to other people who are trying to participate to have one person taking up so much space.

  7. “…please explain how, exactly, your plan for cats will work better than TNR.”

    Almost easier to to explain how it couldn’t possibly work worse:

    “…virtually no information exists to support the contention that neutering is an effective long-term method for controlling free-roaming cat populations.” “…free-roaming cats do not appear to have sufficient territorial activity to prevent new arrivals from permanently joining colonies.”

    Levy, Julie K., David W. Gale, and Leslie A. Gale. Evaluation of the Effect of a Long-Term Trap-Neuter-Return and Adoption Program on a Free-Roaming Cat Population. Journal of the American Veterinary Medical Association 2003, 222(1): 42-46.

    • As I’ve said several times now, it doesn’t get you anywhere to say that TNR doesn’t work, because your preferred solution of catching and killing feral cats is not politically viable in the cities and suburbs where the great majority of feral cats actually live. You cannot point to any American city in this century that has had a comprehensive, sustained (at least every two years) program to round up and kill all feral cats – because such a program has not been approved in any city, and never will be approved.

  8. Never say never. I know, as I have family in Australia and spend considerable time in that country, that there were and still are Australian cat lobbyists saying the same. I’ve debated them. Nonetheless their conservation agencies are going ahead, because they recognize that doing nothing will result in the irrecoverable loss of much of their unique native wildlife. They also recognize that TNR = doing nothing.

    And these are the points you overlook in your response:

    TNR doesn’t reduce feral cat populations, even according to the only TNR proponent who has actually attempted a rigorous study on it (and despite her cooking her numbers). The rest of the cat-hoarders and feeders aren’t even keeping shot records, let alone accumulating meaningful data.

    Therefore pursuing a failed policy isn’t going to accomplish anything meaningful–which is precisely your objection to ‘trap-and-kill’. But what I advocate has never been tried against this species in North America, although it has been successfully waged against other species.

    It has also been waged successfully on a smaller scale against invasive cats, and dogs, and foxes, and goats, and plants, elsewhere. I refer you again to the IUCN website, wherein you will find 41 peer-reviewed scientific studies documenting such efforts. One study performed in northwest Mexico even provides instructions on mounting local-level eradication programs against feral cats.

    Your primary objection for a mass eradication campaign is predicated on lack of political will among Americans. I remind you that can change. When I was a teenager to even suggest that a black American could be president would have been greeted with incredulity and dismissed as impossible. Just like you’re dismissing my proposal now.

    The only question remaining is how much ecological destruction will be tolerated, and how many irreplaceable North American species will be lost, before there is sufficient political will to stop listening to the ‘pet’ lobbyists’ and their corporate sponsors’ selfish objections and do what needs to be done.

    • People’s attitudes can and do change, of course, but I think people’s attitudes are changing opposite to the way you hope for. You sneer at ethical concerns regarding the species you would like to see wiped out, but those ethical concerns are growing. Conservationists would do better to realize this and try to work with it rather than labeling people who object to mass slaughter of intelligent creatures as Bambi-huggers.

  9. No, I’m not sneering at ethical concerns–merely espousing different ethical priorities. Specifically, emphasizing the importance of species-level survival of native organisms over individual survival of selectively bred and debased invasive one.

    And the direction of ‘attitude shift’ will only continue in the direction you would prefer as long as enough people continue to swallow the lie that TNR works to reduce feral cat populations. And the lie is being exposed in more than one municipality in this country as we speak.

    And I would of course question the ethics of claiming efficacy of a policy that’s been pretty much proved to be an abject failure.

  10. Australia does not have the answers to this debate. There is no way that our invasive species are going to be eradicated, they are here to stay. Here is QLD dingos are still considered pests and they have been here +/- 6000 years, haven’t been eradicated yet despite bounties, free for all on shooting and tons and tons of poisonous baits being dropped.
    Political grand standing aside, there is not really a will to tackle feral cats as even our ill informed politicians realise that eradicating all “feral” cats falls into the too hard basked. Besides, without feral cats, dogs, pigs and cane toads to blame we might have to take some responsibility for poor farming practices, bad urban planning,unchecked expansion and development. By far the biggest impact on native wildlife is humans not cats.
    By the way, Mr Minshall, you must be a true ray of sunshine to have come visit.

    • Moderator–hit ‘post’ button in error. Following, if accepted, is the reply I wish to make to Eileen Fletcher:

      Heh. Concerning your last little comment, Ms. Fletcher, my two granddaughters in Sydney seem to think so. And theirs (and my son’s) opinions in that regard are pretty much the only ones that matter to me.

      And this tiresome strategy of ‘deflection’, as if somehow the very act of drawing attention to the egregious destruction feral cats inflict on native wildlife means those who do so have no concern for pollution, poor farming practices, urban mismanagement and unneeded development is…what’s the expression…”a load of dingo’s kidneys”.

      How does eliminating an invasive predator alleviate or even address pollution or habitat loss? It doesn’t and we don’t need to ‘scapegoat’ cats to deflect attention away from these very serious problems. It is absurd to claim that we want everyone out in the bush shooting cats so they won’t see the high-rises and shopping malls being built-up behind them, or the filth being pumped into the Georges River. I submit that such misdirection is precisely what the feral cat advocates are up to–in reverse.

      I’m uninterested in COMPARING problems, particularly when they’re brought up as a distraction merely because the proposed remedy negatively impacts on domestic animals you and those like you find emotionally appealing. But I do wish to address, and hopefully resolve, the ones I can–in this case so my granddaughters at least have a chance to grow up seeing wallabies, shingleback skinks, galas, king parrots, White’s treefrogs, kukaburras, carpet pythons, echidnas and bandicoots somewhere other than in a picture-book of extinct Australian animals.

      Thank you.

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