Claims made by trap-neuter-release (TNR) volunteers are not always true but TNR is effective and humane

TNR volunteer. Great people as far as I am concerned. Image in public domain.

There is a study online dated 2009 (Critical Assessment of Claims Regarding Management of Feral Cats by Trap–Neuter–Return) so it's quite old. I can't read the entire study but I can read the summary which states that the claims that TNR volunteers make are all untrue. These are some of them:

• Feral cats only harm wildlife on islands and not on continents
• Feral cats fill a natural niche and don't contribute to the decline of native species
• Feral cats don't spread disease or they don't act as a reservoir for disease
• TNR eventually reduces the number of feral cats to zero
• TNR managed feral cat colonies "resist invasion by other cats".

Harming wildlife

We know that feral cats harm wildlife. It is common sense. They need to eat and in order to eat they need to kill small mammals, marsupials, insects, birds and reptiles. It depends where they live but there is quite a lot of killing. People who dislike feral cats - and there are many scientists who dislike feral cats - exaggerate the amount of killing by this type of cat. 

They take small sample sizes and work out how many animals the cats kill and then they extrapolate that figure and argue that an entire nation of feral cats kill so many billions of animals. This is liable to produce inaccuracies. 

We can't rely on the numbers disseminated by experts as published in studies on websites such as Google Scholar. We certainly can't rely on the numbers stated by Australian conservationists when arguing that they should exterminate all feral cats on that continent.

But feral cats certainly do not only kill small animals on islands. The reference to islands is there because it is known that on several notorious occasions it is argued that feral cats have made extinct certain small species on islands because those animals had nowhere to escape to. The feral cat dominated the island as a top predator and wiped-out small animal species.

Don't contribute to the decline of native species

This is a big argument. I remember, years ago, the Royal Society for the Protection of Birds saying that there was no evidence at that time (about 12 years ago) that feral cats endangered the survival of a species of bird. Yes, feral cats killed birds but not in sufficient numbers to put a particular bird species on the brink of extinction. And I should add that a lot of the birds that feral cats eat are old, dying or dead birds.

It may interest you to think about dead birds. How many dead birds do you see? When you walk in the park or anywhere else, you never see dead birds do you? And yet millions and millions of birds are dying every day. That's because while animals like foxes and feral cats are eating them.

In short, there is no hard evidence as yet that feral cats, preying on birds, jeopardises the survival of a species. And the same applies to any other animal species. Except, as mentioned about island wildlife where there are differences.

I don't want to defend the feral cat unjustifiably. They do kill a lot of animals and this is of great concern to conservationists. But my argument has consistently been that humans kill a lot more animals than feral cats and are doing so as I dictate this because global warming, an indirect consequence of human behaviour, is killing millions of animals every day. 

An example of that would be the massive floods in Australia coupled with the massive wildfires on that continent. It is said that the latter killed over a billion animals often small mammals, marsupials and reptiles, the kind of prey killed by feral cats. That's the point I'm making.

To global warming you can add herbicides and insecticides used by humans in intensive farming which kills many animals. You can add tall buildings and windfarms which kill many birds. All human commercial activity kills animals because it might lead to deforestation for example. There are numerous ways that humans indirectly kill billions of animals. Humankind should stop being hypocritical about wildlife conservation and look to themselves first is the primary destroyer of nature.

Feral cats don't spread disease

Often you hear spokespersons for local authorities saying that feral cats have to be eliminated because they have a negative impact upon the health of residents. There is no hard evidence to prove this. None whatsoever. I've never seen it. If you can refer to an example then please comment. There is exaggeration about feral cats acting as reservoirs of diseases.

It is notable that the Covid-19 pandemic was caused by humans misbehaving in killing wild animals in a wet market in China in an unregulated way. Nothing to do with feral cats. Or the pandemic was caused by the escape of pathogens from a bio lab in Wuhan, China. Once again, a human-created massive problem. Let's look to humans for the cause of the spread of disease first before we criticise the feral cat which is the victim of human carelessness.

TNR reduces a colony of feral cats to zero

If a volunteer says that TNR reduces a feral cat colony to a population of zero, they are wrong. It might happen from time to time but in general TNR doesn't produce a zero population. It stabilises the population and it means that the cats are looked after to a certain extent and therefore it is a humane practice. Sometimes people dump cats and they add to the colony. Numbers are often significantly reduced and the resulting colony size is manageable.

The volunteers are happy in caring for the cats and the residents of the area are usually happy that the feral cats are being managed. Sometimes people argue with volunteers and they hate TNR volunteers and there can be some nasty altercations but by and large the management of feral cat colonies works out well.

Resisting invasion by other cats

I don't think that this is correct. If TNR volunteers are saying that their work helps to resist the invasion of the colony by other cats it is wrong to say that in my opinion. As mentioned above sometimes people see a feral cat colony as an opportunity to get rid of their cat because they know that somebody else will look after him or her. That's immoral and it doesn't help the TNR volunteers.

One last point, if you kill all the feral cats rather than look after them and neuter them, you end up with this well-known condition where you create a vacuum and other feral cats come into that vacuum. Killing feral cats is arguably less effective than gradually reducing their numbers through TNR programs. #

The problem for a lot of authorities is that the processes too gradual. Politicians need to see instant results to satisfy the electorate. That is one reason why the authorities criticise TNR programs sometimes. More enlightened local authorities support TNR programs and praise the work of these wonderful volunteers.