Perhaps the most alarming headline announcing the findings of an Australian study last week was from Newsweek: “Cats Kill One Million Birds Per Day Pushing Many Species to the Point of Extinction.” In fact, the research itself makes no mention of extinctions. Indeed, as the researchers themselves explain in the paper’s abstract, “it remains challenging to interpret this mortality tally in terms of population viability or conservation concern for Australian birds.” 
Challenging, in part, because the mortalities attributed to cats* account for only “about 3.5% of Australia’s terrestrial bird population.”1 Funny, there was no mention of this little detail in Newsweek piece—or in the phys.org article upon which it was apparently based.
Far more troubling, though, was its omission from the media release announcing the publication of the research.
Granted, any broad-scale mortality estimates have their limitations. As the authors admit:
“…the ecological and conservation significance of these kill tallies is difficult to contextualise, because (1) there are no reliable estimates of the total population of birds in Australia; (2) predation may fall disproportionately on some bird species; (3) some bird species may be able to sustain high mortality rates and maintain viable populations but others may not; and (4) as demonstrated here, there is substantial spatial variation in the numbers and proportion of birds killed across Australia.”1
All perfectly valid points. But all of this was known, or could have been anticipated, prior to embarking on the research. So why bother with the project at all?
Bury the Lede, Bury the Truth
The organization behind the research is the Threatened Species Recovery Hub of the National Environmental Science Programme, “a collaboration of 10 leading Australian universities and the Australian Wildlife Conservancy, to undertake research to support the recovery of Australia’s threatened species.” The Hub was also responsible for a related study published earlier this year, unleashed with enough drama to preempt any logical follow-up questions: “Feral cats cover over 99.8% of Australia.”
As with last week’s media release, there’s considerably more to the story. Not that the media demonstrated any great interest in looking past the headline handed to them. Instead, they ran with it—which seems to have been the Hub’s intent.
“Australia Has More Feral Cats Than Internet Coverage,” proclaimed Gizmodo Australia. And Smithsonian.com used the opportunity to once again vilify “fluffy murderbeasts” (as they’ve now dubbed domestic cats) and promote Cat Wars (about which the organization seems schizophrenic—eager to embrace it when it serves their purposes but unwilling to admit they played any role in its publication and promotion).
But “cover” is, as it turns out, a relative term.
Of the 91 data sources used by the researchers, half documented cat densities of 0.67 cats/square mile or less. That’s just two cats for every three square miles. Or about 127 cats “covering” Chicago (considerably fewer than the 182 Starbucks locations in the city).
So, covered? Not so much.
Meanwhile, arguably the project’s biggest take-away received remarkably little attention. According to lead-author Sarah Legge, the estimated number of Australia’s feral cats is now “between 2.1 million when times are lean, up to 6.3 million when widespread rain results in plenty of available prey”—far fewer than the previously suggested 20 million.
One would imagine that these studies would have policy makers rethinking Australia’s War on Cats—with its price tag of $AU30 million and counting. Which is exactly the problem: such a move seems, sadly, relegated to our imaginations.
* The mortality estimates have their own “challenges.” The tally attributed to pet cats, for example, were inflated by 29 percent “to account for the number of birds killed but not returned to the cat’s home,”  but this upward adjustment was based on the authors’ misreading and/or creative interpretation of three of four studies cited. [2–4]
- Woinarski, J. C. Z.; Murphy, B. P.; Legge, S. M.; Garnett, S. T.; Lawes, M. J.; Comer, S.; Dickman, C. R.; Doherty, T. S.; Edwards, G.; Nankivell, A.; Paton, D.; Palmer, R.; Woolley, L. A. Biological Conservation 2017, 214 (Supplement C), 76–87.
- Kays, R. W.; DeWan, A. A. Animal Conservation 2004, 7 (3), 273–283.
- Loyd, K. A. T.; Hernandez, S. M.; Carroll, J. P.; Abernathy, K. J.; Marshall, G. J. Biological Conservation 2013, 160 (0), 183–189.
- 4George, W. The Wilson Bulletin 1974, 86 (4), 384–396.