It’s a fact. Cats kill birds.

For whom the bell tolls: cats kill more than a million Australian birds every day

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On the prowl in the outback.
Hugh McGregor/Arid Recovery, Author provided

John Woinarski, Charles Darwin University; Brett Murphy, Charles Darwin University; Leigh-Ann Woolley, Charles Darwin University; Sarah Legge, Australian National University; Stephen Garnett, Charles Darwin University, and Tim Doherty, Deakin University

Cats kill more than a million birds every day across Australia, according to our new estimate – the first robust attempt to quantify the problem on a nationwide scale.

By combining data on the cat population, hunting rates and spatial distribution, we calculate that they kill 377 million birds a year. Rates are highest in Australia’s dry interior, suggesting that feral cats pose a serious and largely unseen threat to native bird species.


Read more: Ferals, strays, pets: how to control the cats that are eating our wildlife


This has been a contentious issue for more than 100 years, since the spread of feral cats encompassed the entire Australian mainland. In 1906 the ornithologist A.J. Campbell noted that the arrival of feral cats in a location often immediately preceded the decline of many native bird species, and he campaigned vigorously for action:

Undoubtedly, if many of our highly interesting and beautiful birds, especially ground-loving species, are to be preserved from total extinction, we must as a bird-lovers’ union, at no distant date face squarely a wildcat destruction scheme.

His call produced little response, and there has been no successful and enduring reduction in cat numbers since. Nor, until now, has there been a concerted effort to find out exactly how many birds are being killed by cats.

Counting the cost

To provide a first national assessment of the toll taken by cats on Australian birds, we have compiled almost 100 studies detailing the diets of Australia’s feral cats. The results show that the average feral cat eats about two birds every five days.

We then combined these statistics with information about the population density of feral cats, to create a map of the estimated rates of birds killed by cats throughout Australia.

Number of birds eaten per square kilometre.
Brett Murphy, Author provided

We conclude that, on average, feral cats in Australia’s largely natural landscapes kill 272 million birds per year. Bird-kill rates are highest in arid Australia (up to 330 birds per square km per year) and on islands, where rates can vary greatly depending on size.

We also estimate (albeit with fewer data) that feral cats in human-modified landscapes, such as the areas surrounding cities, kill a further 44 million birds each year. Pet cats, meanwhile, kill about 61 million birds per year.

Overall, this amounts to more than 377 million birds killed by cats per year in Australia – more than a million every day.

Which species are suffering?

In a related study, we also compiled records of the bird species being killed by cats in Australia. We found records of cats killing more than 330 native bird species – about half of all Australia’s resident bird species. In natural and remote landscapes, 99% of the cat-killed birds are native species. Our results also show that cats are known to kill 71 of Australia’s 117 threatened bird species.

Birds that feed or nest on the ground, live on islands, and are medium-sized (60-300g) are most likely to be killed by cats.

Galahs are among the many native species being killed by feral cats.
Mark Marathon, Author provided

It is difficult to put a million-plus daily bird deaths in context without a reliable estimate of the total number of birds in Australia. But our coarse assessment from many published estimates of local bird density suggests that there are about 11 billion land birds in Australia,
suggesting that cats kill about 3-4% of Australia’s birds each year.

However, particular species are hit much harder than others, and the population viability of some species (such as quail-thrushes, button-quails and ground-feeding pigeons and doves) is likely to be especially threatened.

Our tally of bird deaths is comparable to similar estimates for other countries. Our figure is lower than a recent estimate for the United States, and slightly higher than in Canada. Overall, bird killings by cats seem to greatly outnumber those caused by humans.

In Australia, cats are likely to significantly increase the extinction risk faced by some bird species. In many locations, birds face a range of interacting threats, with cat abundance and hunting success shown to increase in fragmented bushland, in areas with high stocking rates, and in places with poorly managed fire regimes, so cat impacts compound these other threats.

Belling the cat

What can be done to reduce the impact? The federal government’s Threatened Species Strategy recognises the threat posed by feral cats, albeit mainly on the basis of their role in mammal extinctions.

The threatened species strategy also prioritised efforts to control feral cats more intensively, eradicate them from islands with important biodiversity values, and to expand a national network of fenced areas that excludes feral cats and foxes.

But while fences can create important havens for many threatened mammals, they are much less effective for protecting birds. To save birds, cats will need to be controlled on a much broader scale.


Read more: The war on feral cats will need many different weapons


We should also remember that this is not just a remote bush problem. Roughly half of Australia’s cats are pets, and they also take a considerable toll on wildlife.

While recognising the many benefits of pet ownership, we should also work to reduce the detrimental impacts. Fortunately, there is increasing public awareness of the benefits of not letting pet cats roam freely. With such measures, cat owners can help to look after the birds in their own backyards, and hence contribute to conserving Australia’s unique wildlife.


The ConversationWe acknowledge the contribution of Russell Palmer (WA Department of Biodiversity Conservation and Attractions), Chris Dickman (University of Sydney), David Paton (University of Adelaide), Alex Nankivell (Nature Foundation SA Inc.), Mike Lawes (University of KwaZulu-Natal), and Glenn Edwards (Department of Environment and Natural Resources) to this article.

John Woinarski, Professor (conservation biology), Charles Darwin University; Brett Murphy, Senior Research Fellow, Charles Darwin University; Leigh-Ann Woolley, Research Associate, Charles Darwin University; Sarah Legge, Associate Professor, Australian National University; Stephen Garnett, Professor of Conservation and Sustainable Livelihoods, Charles Darwin University, and Tim Doherty, Research Fellow, Deakin University

This article was originally published on The Conversation. Read the original article.

“Don’t you dare harm my baby!”

Yesterday, I encountered a gull and realized “Oh! You’re a baby!”

I think this was the second time in the past five years or so that I’d seen a young from close enough that I was able to detect the messiness of its feathers. The first time, I mistook it for a gull that had had an encounter with hot exhaust gases. *blush*

I looked up. Would there be a parent around? Sure enough, an adult was sitting on the roof above the youngster and sure enough, it swooped down and signalled “Don’t you dare harm my baby!” by reaching a point no more than about a meter over my head – I instinctively ducked – before it swooped upward again.

Message understood. Roger, willco, over and out.

So I walked on. The parent returned to its high perch, literally watching over its young.
Then I took this photo, with my old mobile.

Solidarity and compassion

There are two kinds of solidarity. Exclusive solidarity is essentially protectionism. Groups rally to stand up for their own kind and do each other favors such as recommend each other and give each other jobs. It exists on the basis of what divides us, what makes us different from others.

Birds do this too. If you are observant and like being outdoors, for instance go for walks, you may on occasion have seen crows appearing from all sides and forming a circle around a crow attacked by someone’s dog. You can also occasionally hear a lot of loud cackling, look up and see a group of magpies around a cat that has climbed into a tree.

Inclusive solidarity, on the other hand, is much closer to compassion. It does not ask many questions and exists on the basis of what we have in common.

Birds do this as well. If for example you happen to have lived with certain parrots, you may be quite familiar with this. I adopted two quaker parrots in 1994 and they both stood up for my cats if they thought some harm might be happening to one of my cats, for example if I had to stuff a pill into a cat’s mouth and make sure the cat swallowed it, for a very good reason. This happened regardless of whether the cat in question was kind to birds or not.

Birds are capable of compassion because they appear to have something called “theory of mind” just like humans do.

I have seen one of my little parrots quickly step forward and snatch a bit of feces off the other bird. It was stuck to a feather. That other bird never even noticed what happened. This was an act of selfless compassion based on the first bird’s reasoning that she would not want to have feces stuck to her own butt and therefore the other bird probably wouldn’t like it either.

I have two kinds of confirmation for this.

In the past, I have seen that particular bird come running down a series of perches (in a huge cage) and then stop short to avoid stepping into fresh feces.

This particular bird was a pretty intelligent rascal who went through phases of pranks involving feces. For a while, she took great delight in pressing her butt against the bars of the open cage to help her aim and then pelt poop at my shoes whenever I sat reading in a chair near the cage, for example. Poopball. Goal! This means that the bird assumed that I would not like getting feces on me and also that she knew that getting feces on my shoes wasn’t so bad.

This bird has forever changed the way I look at birds. I used to see birds as completely devoid of anything resembling human intelligence. Birds flew, hopped and tweeted. That was it. Oh, and they laid eggs, too. Particularly the flying made me experience them as distant, I presume. Removed. Different.

I couldn’t have been more wrong about that.

I still remember the look that parrot – the longest-living of the two – gave me when I apologized to her for it having taken me so long to realize how intelligent she was. How stupid the two of them must have thought we humans were and how desperate they must have felt at times. “Is she ever going to get it?” She was a very wise one, that one. (She started showing me, by anticipating my moves and wishes and acting on them, all by herself. The first time that happened I was stunned.)

We’d all do ourselves a favor if we could focus more on inclusive solidarity and less on protectionism. I believe we’re slowly getting there.