Gareth Morgan and his cat killing experiment*

By Grant Jacobs 31/01/2013 15


I challenge Gareth to do some science.

Gareth Morgan wants to help New Zealand wildlife by restricting cat numbers. Last night on Campbell Live, Gareth Morgan was brought back on the show for a second run to make an announcement. As I understood it he is offering to pay the SPCA $5 for every cat that is not taken up by a family and micro-chipped, to euthanatise it rather than than, as he implied, have them release it.

If he doesn’t plan the experiment, measure the outcomes and test the results, no-one will have any idea if it helped or not.

I’m not going to argue his final point. Others say it’s true that in some locations cats are released. Something for investigative journalists to look into. (Putting it as the SPCA “has been taken over” isn’t helpful to my mind.)

I’m also not going to argue if these cats not taken up by families should be killed or not. Others can debate the science and morality of that.

But I will say that if you are going to do this, do it properly and treat it as an experiment. Hire ecologists. Plan it. Measure the current situation. Measure the resulting situations. Compare them.

If you just stick the money in without measuring the impact, you’ll have no idea how much effect it had and what effect it had.

Gareth is entitled to put his money where he wants. It’s his money, after all. But it’s evidence that will show if it was to good effect or not.

Anecdotal claims after the fact won’t cut it.

An important element when determining if one thing caused a particular outcome is to know of or rule out the role of any other things that might have caused the outcome. You want to deal with the different factors (variables) that might affect what you’re measuring.

I’m not a field ecologist. The details should be dealt with by people who are. Ecologists will know what previous studies have shown and have a better idea of what is important or not, but I imagine factors like location,[1] type of wildlife, predator competition and environmental conditions[2] all play a role.

You’d have to measure the outcome on each of these.

Don’t say obvious “it’ll be obvious.” That’s just one giant anecdote and will count for diddly-squat.

Don’t say you can work it out afterwards. That just doesn’t work. You have to plan data analysis before you do the experiment.[3] In addition to the usual making sure you have a procedure that will yield useful results, you’ll be wanting to measure how things are ‘before’ doing anything to compare with later.

If you want to tackle this, measure the effect of what you’re doing. Perhaps run a pilot programme or three or whatever it takes. In different settings, perhaps. Fund ecological studies.

Show it works.

Footnotes

Facebook users can see the Campbell Live page for early commentary, e.g. these posts.

* I know my title is just a little unfair. But I’ve got your attention now?

1. I’m thinking of within a large town or city, rural outskirts or fringe of small town, rural farming location, out in the (remote) bush, that sort of thing. (There’s a related thought: what locations matter most in preserving bird life?)

2. The weather, fire, etc. All the things that affect wildlife numbers.

3. I’m a computational biologist. Data analysis is a large part of what I do. For one post lamenting this issue, see External (bioinformatics) specialists: best on the grant from the onset.


Other articles in Code for life:

Thieves in gold-mining era campsites

Vaccination – why learn the hard way?

Mad on Radium

When things grow wild – post-earthquake natural succession in Christchurch gardens

Sea stars and mosaics

 Haemophilia – towards a cure using genetic engineering


15 Responses to “Gareth Morgan and his cat killing experiment*”

  • Reducing the number of cats is a good outcome in itself, without the added benefit (or otherwise) of birds saved.

  • Perhaps, but it’s not why Gareth is doing it. The question here is if what he is doing will actually achieve what he wants it to. If he doesn’t set it up as a formal study, we simply won’t know.

  • Wayne Linklater has a few more articles on this topic – see his latest and the links there to earlier articles: http://sciblogs.co.nz/politecol/?p=563

    Two quick points from his posts. He refers to Gareth’s money as for one particular SPCA centre, rather than the SPCA as whole. The released cats are neutered. Readers can follow the details there.

    One thing I downplayed while editing my piece (in order to focus on just one point) was the location of these efforts – see footnote 1.

  • It’s true that without a formal study, we would never be able to say in this case. But the general consensus of conservation biologists is that TNR is at best expensively useless and often actively harmful, based on multiple studies (e.g. Longcore 2009 [1]). This is pretty much regarded as ‘settled’, inasmuch as any conservation issue can be.

    I am a conservation biologist, and I intend to make my money doing studies like the one you propose. But given that each study has costs, at what point do you think we should we stop studying each conservation intervention, and just start doing conservation?

    Longcore, T., et al. (2009) Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return. Conservation Biology 23, 887-894

  • Shane – It’s a rum one isn’t it? It’d be interesting to learn what research has led him to his suggestions.

    It seems Bob Kerridge has rejected Gareth Morgan’s offer, saying the cats are released to ‘urban colonies’: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10862577 (The piece also features quotes from a transcript of Gareth’s statement to Campbell Live.)

    (This is looking more like two boys having fisticuffs. At least the media impression does.)

  • For those continuing to follow this story, Bob Kerridge has appeared on Campbell Live tonight. A video of his segment should be on their website sometime later tonight or tomorrow.

  • Re: fisticuffs.

    A little bit, yes. But still, someone is crowbarring my preferred breed of science into the media for a semi-extended period of time. I’m receiving requests for copies of academic papers on cats as introduced predators from legitimately-interested bystanders, and getting asked to weigh in on people’s debates. I, for one, am enjoying the side-effects of their wee bout.

  • From where you’re coming from the attention won’t hurt!

    Do you also give them a potted account of the wider backstory? (Ferrets and their introduction, rats, etc.) The narrowness of focus on just/mainly cats bothers me, in particular what approaches to take in what locations.

    (I’m not an ecologist, but I can’t help but think different locations will have different issues and will favour different approaches. Also thinking about where native wildlife is v. where SPCA centres are, etc. Not happy with either “combatants” lines on the wider issues – Gareth seemingly brusquely dismissing these as problems for later and Bob’s line about “the balance of nature” sounding too simplistic and romantic. [Hey, I can put in the odd poke myself…!])

  • Re: backstory. Kind of. In my first post on the topic I put forward an option for dealing with multiple introduced predators at once, and outlined some of the advantages that dealing with each would entail.

    I think the advantage of going after cats (especially owned ones) is that no-one really has made much noise about them in the public sphere before. Public perception-wise, I have the impression that this is breaking new ground. People knew that possums were a problem, they knew that rats were a problem – they didn’t really realise how big a problem cats are. There’s an excellent figure in Tennyson & Martinson’s ‘Extinct Birds of New Zealand’ that shows the number of species thought to have been driven extinct by each introduced mammal, and cats are right at the top of the list (I would cite exact numbers, but I’m in the process of moving so that book is buried in a box on a boat). I’ve been seeing tons of comments about how rats are a bigger problem, or possums, and that we can just ignore cats. I think that view needs to be challenged.

    Bob’s lines about the ‘balance of nature’ have caused me to spit-take and froth at the TV a couple of times, now. If he thinks that there is anything ‘balanced’ or ‘natural’ about maintaining artificially-high population densities of an introduced predator by supplementarily feeding them, either as pets or as TNR colony cats, he needs to be forcibly introduced to a first-year ecology textbook.

    The reality of cats is that, where they are kept as pets in areas that natively have a medium-sized mammalian predator, their population densities are many times higher than the density of medium-sized predators that would be found in an unmodified environment. This extracts a crushing level of harvest on anything cats can eat, even if it is not their preferred food source. The phenomenon is known as ‘hyperpredation’. In places like New Zealand, the problem is of course worse, because our native fauna are not adapted against mammal predation.

    Do not get me started on his ‘black death’ fearmongering. Grrr.

    I take concerns about mesopredator release a bit more seriously – we have observed it before in thin food webs when cats have been totally eliminated, for instance in the cat/rat/cook’s petrel system at altitude on Little Barrier. I’m less concerned about it in this case because
    1) rat bait is cheap, effective, and (used correctly) doesn’t kill birds,
    2) rat population densities are generally more susceptible to food limitation than predator densities,
    3) Gareth isn’t actually proposing the elimination of cats – just a reduction in the population density to reduce their hyperpredator status. If we start talking cat elimination (like on Stewart Island), then we should start looking seriously at elimination-order effects. Before then, it is a terrible argument to support an invasive predator.

  • I realise people will have moved on, but for whatever it’s worth to the odd person who passes this way :-

    In response to a letter to the editor in the Otago Daily Times (2nd February, 2013), Sophie McSkimming, the executive officer of the Otago SPCA wrote,

    “The notion put forward by Gareth Morgan that all domestic (companion) cats should be phased out of existence is totally rejected by the SPCA. Research clearly disputes this presumption in that fewer than 50% of of domestic cats hunt at all, the remainder preferring vermin as prey, with birds being a minor target, with the rare native species representing less than 1% of their total ‘kill’”

    They go on to say that “At the present time SPCA Otago does not trap, neuter and release wild cats.”

  • “At the present time SPCA Otago does not trap, neuter and release wild cats.”

    Is this finessed? Do they TNR any cats AT ALL?

  • Hm. It seems like they’re deep in denial about the amount of damage that domestic cats cause. I wonder if they’ll turn out to be susceptible to evidence, if it’s presented loudly and repeatedly enough.

    Also: be careful interpreting SPCA’s terminology. They define ‘feral’ cats as cats which are not reliant on humans for any part of their wellbeing, ‘stray’ cats as cats which are unowned but reliant on humans in some way, and ‘companion cats’ as kept pets. I’ve read a couple of statements by them which say that any cat living in a city or near human habitation is (essentially by definition) not feral, because any cat in a city will, at some stage, shelter from the rain under something constructed by a human or eat something discarded by a human. I wouldn’t be at all surprised if they’re using ‘wild’ the same way as their definition of ‘feral’ in this statement.

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