In the United States alone, outdoor cats kill approximately 2.4 billion birds every year:https://abcbirds.org/program/cats-indoors/cats-and-birds/
I don't really know what's going on in other parts of the country. Are there stray cats just roaming the forests? I can't imagine why anyone would have incentive to exaggerate these numbers though.
> Un-owned cats, as opposed to owned pets, cause the majority of this mortality.
So, we should start culling feral cats.
The statistic about extinct birds was done in Australia, and included foxes, stoats, rats, and other small mammals, as “alien predators” contributing to the killing of birds in Australia.
The number does sound high, and the paper acknowledges that, but I guess something published in Nature should be taken seriously.
I’ve only had time to barely skim it, but it appears that they might be saying the majority of the issue comes from un-owned cats that roam free, not cats that live with (and are fed by) humans in a house. I think they took data on the number of kills per cat and then multiplied by the estimated number of cats.
Edit: I also looked for rebuttals or critical review, and came across a defense of the paper by the same authors, which has references to the criticism: https://link.springer.com/article/10.1007/s10530-018-1796-y
They address multiple claims about misusing extrapolation in their defense article. I’m not defending them because I don’t know enough about this and it would take a long time to fully evaluate the methodology and criticisms. But, I really doubt this is as obvious or clear-cut as you suggest. It seems like a bad idea to jump to the conclusion that they’ve made the simplest of statistical mistakes and got it past the reviewers at Nature Comms. This journal is one of the more difficult to get into. The authors appear to have tried to be careful, and moreover they are at least using actual data, where the rest of us arm-chair commenters are basing our ideas off of beliefs and emotions and wishes for certain outcomes, which are all notoriously inaccurate, right?
Another thing we do know is that behaviors tend to lump into distributions (often Normal Distributions), and that given enough samples, we can make pretty strong claims about whole populations (as long as you’ve captured true representative samples). I did skim the paper enough to see that they put together probability distributions for the bird and other-mammal killing rates. They explicitly acknowledge a pretty wide range of feline hunting rates, no?
Less facetiously, it's interesting that the turbine birds are somehow more valuable or special. I would imagine that would be easy to prove, and I would expect to see a lot of "America-hating wind turbines murder 100,000 Bald Eagles a year" but for some reason I never see that.
Others have pointed out that there probably is a difference in the kinds of birds killed by cats vs wind turbines, but I've not seen any report breaking down the deaths by species (not that I've looked).
Tom and Jerry tried to warn us.
But I suspect you have a small number of cats that are just murder machines, some that eat birds to stay alive, and the vast majority of fat housecats that just eat chickens via a giant grinder at the pet food store.