There are many cat owners, some of whom are my online friends, who strongly support keeping cats inside all the time. This article is not a criticism of them because I understand the motivation to keep cats inside. It is meant to be a fairly cold, scientific discussion about cats and conservation as at early 2019. I have a fairly neutral stance on this issue.

Concrete evidence
There is no concrete evidence (I emphasis the word ‘concrete’) that outside domestic cats affect wildlife populations year-on-year at a national level. There is a copious amount of speculated statistics on cat predation but it has to be admitted that the evidence is inconclusive that outside cats have a permanent negative impact on wildlife populations nationally (baring the known extinctions on small oceanic islands).
Therefore, in terms of wildlife conservation it is logical for cat owners who want to let their cats go outside to keep doing it. Clearly there are other reasons such as in the US coyotes preying on cats but this page concerns conservation reasons for keeping cats inside, full-time. This is the reason hammered home by ornithologists.
Also for the past ten years there has been a growing campaign against wandering domestic and feral cats. These online campaigns may have hardened the hearts of many cat owners to reject calls to keep their cats inside.
Australia is a testing ground
All of the studies on cat predation are based on ‘estimates’ and guesstimates. You only have to read the studies to constantly see words such as ‘perhaps’ and ‘estimated’ and the conditional tense being used. They often conclude by suggesting further research i.e. they are inconclusive studies. The conclusions do not present hard evidence at a national level. It is only such evidence which will convince cat owners to alter their ways.
For instance the experts in Australia don’t even know the number of feral cats in their country so how can the authorities begin to calculate the impact they have on wildlife? Their estimates of feral cat population size varies wildly.
Also in Australia, where restrictions have been placed on outdoor access for domestic cats, there appears to have been no great improvements in population sizes of animals upon which cats prey.
Cats benefit conservation?
Then there are counter arguments. Cats prey on rats and rats eat bird’s eggs, young birds and mammals. Consequently, in certain areas cats may have a positive impact on wildlife populations.
We constantly read of high number of birds killed by cats in the USA. The numbers are said to be in the billions and yet we don’t see this mass slaughter translated to observed evidence.
Habitat loss
In the UK, the RSPB say that habitat loss is the biggest bird killer and that blue tits are common prey for cats yet over the last 25 years this bird species has grown in populations size. I don’t want to harp on but there is no doubt that humans have a far greater negative impact on wildlife conservation than cats so lets prioritise that.
Until there is concrete evidence that cats have a lasting negative impact on wildlife population sizes, cat owners will be justifiably sceptical and carry on as they are.

I am grown up (76) and I am thinking far more widely and deeply than you it seems. Humans are also invasive species and humans made domestic cats invasive species. Much human failure. You are saying that the only way cats can be domesticated and companions to people is if they are kept indoors all their lives no matter if the home is a bedsit. That’s advocating animal cruelty as far as I am concerned. When the wildcat was first domesticated about 10,000 years ago there was no concept of keeping cats indoors. It is only recently, over the past less than 30 years that people like you insist on full-time indoor cats to protect wildlife. The reason is because wildlife is under dire threat thanks to crappy human behaviour! Humans, directly and indirectly are in a different league when it comes to killing wildlife. Think about that and what humans can do to protect the planet and nature. Humans can’t even stop burning fossil fuels when knowing that they cause globale warming which kills them and wildlife.
You are narrow-minded and programmed to hate the concept of indoor-outdoor cats. Poor thinking in my view. You sound like an arrogant, bullying AH I know called Ken Flick. You aren’t him are you by any chance? You certainly don’t have the guts to disclose your real name. If you are him: F off.
It’s massively irresponsible to allow one’s cat outside in any circumstance. Domestic cats are an invasive species anywhere in the world and should not be allowed to damage fragile ecosystems of which they are not and should never be a part of.
Responsible cat owners know this. It’s the selfish narcissistic owners who gaslight the world that their precious bred killers are nothing of the sort and innocent of their nature to search and destroy who are the problem, like this inane article’s author and his flying monkeys.
Grow up. Stop feigning ignorance. You know you’re wrong and your actions evil. Stop being evil and ruining the world for everyone else. You may not have children to pass on this world to but we do so f… you!
Frances, I don’t read these troll comments or hardly do, so I don’t know what he said or what you are referring to on this occasion. I guess he wants to win an argument. It does not interest me. He’s been banned. I got to it late because I have been busy doing other things.
I really appreciate your comments though 🙂
Quote: “I accept your surrender.” I did not know this was a battle of wits. 🤣 Michael, that was no big deal. I know that you do not like us to interact with trolls. I just had to leave a statement because this is a feline informational website. I am not here to do hours of research and look up statistics to refute or satisfy one person’s skewed viewpoint. If I wanted to argue, I would join a debate club. 😼
Frances, sorry you had to put up with the troll Holden. He has been banned. I got to him late I am afraid.