Is killing animals an effective way to regulate populations?

Nature Talk
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From the article (PNAS): “Definitive evidence on the efficacy of lethal control is hard to come by. Arguments for and against are infused with questions about ethics as much as the science.”

On November 23, 2023 - I observed a Barred Owl on my deck railing - perched on a water dish - and posted here - https://www.inaturalist.org/observations/192221322
and this article (in PNAS) discusses the issue of the Barred Owl - which I did not know (at that the time- 2023) was a controversial topic - having just moved from the intermountain west to the Pacific Northwest…

(From the article: “The owl case is one of the most meticulously studied. Barred owls, native to eastern North America, have spread west over the last century (an expansion unintentionally facilitated by humans) and are now encroaching on the last western old-growth forests where threatened spotted owls roost. The hope is that by killing thousands of the encroachers, wildlife biologists can stabilize spotted owl populations.”

I could not believe that this owl (in my backyard) was the subject of a much larger topic of managing populations. I mean to say (even as I have a undergraduate degree in Wildlife Management) that I did (and do) not think I could kill this animal - this Owl (or any Owl) to help regulate populations…which I admit here that I find Owls (in general) to be in some ‘sacred’ category vs. other animals I learned about that were “encroachers” or invasive (e.g, Nutria; Red Imported Fire Ant) to ecosystems.

And so to recent article: April 16, 2025 -
“Is killing animals an effective way to regulate populations”
For discussion and viewpoints - published in Proceedings of National Academy of Sciences of the United States of America (PNAS) - free access
https://www.pnas.org/doi/10.1073/pnas.2506919122
https://doi.org/10.1073/pnas.2506919122
with PDF version

Many species (e.g., raccoons; coyotes) are reviewed in this article as examples of where science and ethics intersect in relation to killing animals to ‘regulate’ populations. Wanted to share the citation/link/article with iNaturalist and Forum participants as I not only observe and identify here (with have preferences with identification) - but I have also have reflected more on ethics, my own selected bias toward some animals, and the role of humans (to some degree) in creating the issues (the problem?) of why ‘we’ need to manage the population(s) to begin with…I look back on my undergrad degree and think it about to this day - that I was learning how to “manage” wildlife as though it needed managing. I shifted gears and went into health sciences with graduate work and then teaching/research in regards to humans and health care (ironically - addressing management systems for people).

In the present, I am a ‘naturalist’ - and the management part - the issue of managing wildlife for human concerns is still here…and for the sake of determining the fate of one species vs. another - as well.

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How close are those owl species? Would they interbreed producing fertile offspring? A hybrid Morse code owl might be more resilient and start spreading.

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Is killing animals an effective way to regulate populations? Yes

Should we kill animals for this purpose? Totally different question . . .

Animal populations are always rising and falling with NO impact from humans. Most of the most interesting mammal species (like rhinos the size of giraffes) arose and went extinct long before humans came down from the trees . . . Continents smash into each other and drift apart. All result in changes in wildlife populations . . .

But today, humans do have a big impact. Probably the biggest impact. So should we kill? That is a philosophical question that I will leave to others . . .

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https://en.wikipedia.org/wiki/Northern_spotted_owl#Hybridization

Doesn’t say anything about fertility.

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Really depends on the species. I volunteer doing invasive plant treatment, and it has a huge impact on the environment, allowing for a more open and natural environment. I would tentatively say yes, but there’s a lot that needs to be considered before taking such drastic measures, obviously.

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I heard birth control was used to control rat populations. For Owls, obviously one would not want a native owl to feed on birth control unintentionally. Yeah, not sure this would work like it does for rats.

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There’s a pretty detailed discussion of this stuff in this topic.

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Hard disagree. I don’t believe animal life is sacred to the same level as human life, although killing them without good reason is still unethical there are many instances in which there is in fact a “good reason.” And I believe part of our stewardship over the earth is to preserve the species diversity to the greatest extent possible.

Dude what? Comparing invasive species control to rape is…one heck of a take

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This definitely has the potential to be a hot button topic that is difficult to moderate on the forum. The original question here focuses on whether killing animals is an effective way to regulate populations, so please keep the discussion focused on that topic. If the discussion veers off and gets too contentious, moderators may close the topic. Thanks!

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Thank you!
I found some discussion on the other other topic as well. Does not look that promising.

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Nothern spotted are as good as gone. They do not spread even under artificially improved circumstances.

Killing large number of barred owls to postpone the inevitable is wrong.

The northern spotted could be saved if there is a habitat for them where they would be competitive against the barred or if a hybrid population could be established that is at least as effective as the barred.

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This is definitely a complex topic. My opinion is that if the owls (or any invasive animal) are negatively affecting and threatening local species, killing them is often the best method of population regulation. As long as it is done ethically, it is okay, but still sad. I don’t know if I would be able to kill an owl, but if there’s no better alternative, then that’s what needs to be done.

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https://theconversation.com/sniping-koalas-from-helicopters-heres-whats-wrong-with-victorias-unprecedented-cull-254996

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How prolificly do they reproduce? If you’ve ever had a cockroach infestation, you will have seen that no matter how many you kill off, if there are any fertile survivors, the population will soon be right back where it was before.

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It is species as a whole, not individuals, that scientifically have an effect on the environment. Ethics aside, scientifically the individual’s only worth is as it functions as part of the whole species. And species are not an arbitrary construct. The assignment of species can be arbitrary but science assumes an objective reality, and the ‘species concept’ is an attempt to designate real, physical, objective natural phenomena- a certain type of evolutionary lineage. The subjective philosophy denying objective truth that is now popular has no place in science. Science and its concepts, including species, are only arbitrary or subjective in so far as human scientists are human with human opinions that are subject to error.

I think this is a much more complex issue than you seem to realize here. You’re saying that it’s fine to allow barred owls to indirectly (outcompete) or directly (prey on) kill spotted owls, because it would violate the rights of individual barred owls to kill them. I’m wording this in a way that I hope will make clear that this is purely subjective. What about the rights of the individual spotted owls? You are picking and choosing. Using your human allegories, would it be ‘ethical’ for the last woman on earth to wipe out the entire male population to preserve her rights? Wouldn’t that be a violation of mens’ rights (many would argue that the right to live is far more fundamental and important)? This whole line of reasoning is a fallacy of bifurcation. There needs to be a middle ground.

Your arguments also all stem from the assumption that animal (using the traditional sense of animal) ethics must be the same as human ethics. What evidence do you have for this? Science shows the opposite, where ‘survival of the fittest’ is the primary driver of microevolution, propagating the species at the expense of the individual. As you get into higher and higher taxonomic levels this theory becomes weaker and weaker, with more opposing evidence, but at the level of species it is a scientific fact.

I agree with these statements, but I don’t see how you go from these premises result in:

Rewording this statement it is the same as “if barred owls kill thousands of spotted owls, this is preferable to killing thousands of barred owls”, which is subjectively picking and choosing.

Your argument is based on subjectively preferring the individual barred owl to the individual spotted owl, and upholding the rights of the individual over the rights of the species (making unnatural hybridization fine in your eyes). This seems to be based primarily on the two assumptions that 1) owls’ rights are comparable to humans’ rights, and 2) species aren’t real. Both of these points are brought into your argument without proving them.

And btw this is meant as purely thought-provocative constructive discussion.

Edit: oh I responded to the wrong post lol sorry Seth :laughing:

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Not to get too involved in the discussion, but if you are going by the idea that humans are just another animal species, wouldn’t that justify us killing other animals? After all, animals kill each other and violate each other’s rights all the time.

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Your posts full of hypothetical murders and other illegal activities are increasing support for culling of owls.

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Since the thread has continued to focus on the ethical issues and stray from the original question as noted above, I’ve closed.

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