Terracotta lures for Victor traps

The problems with food based lures are well known to many of you: mould formation, stealing, ants, the need to re-bait, and so on. The clever people from Connovation, Bofffa Miskell and Nara/Futura (I have no affiliation to any of these) have come up with a wide range of scent lures for various applications.

https://boffamiskell.co.nz/news-and-insights/article.php?v=the-newest-predator-control-tool-from-boffa-miskell

https://www.futura-germany.com/product-solutions/nara/

There are a number of ways to use these lures, but one way is to soak a porous substrate with the liquid lure and place the substrate in the trap’s bait receptacle. Connovation sells terracotta substrates for several types of traps, and Nara sells polymer substrates for the same purpose.

What’s missing at the moment is a terracotta substrate for standard Victor traps. Until someone decides to sell these, here is my homemade version.

  • Find an old terracotta plant pot saucer
    This needs to be porous - some are more porous than others - check that it is porous by sitting it in a pool of water and verifying that the water soaks through to the surface - this may take an hour or two. The wall thickness of the saucer bottom needs to around 6 mm or less to fit in the trap paddle.

  • Cut the saucer into approximately 15x15x6 mm pieces
    I used a Dremel with a diamond saw wheel. You could also scribe and break the saucer into pieces if you are less concerned with esthetics. The rats probably don’t care. Some pieces will work, some won’t. Dry/clean (a tiny bit of detergent won’t go amiss) the pieces/substrates for use.

  • Prepare your yellow Victor trap paddles
    You can either cut/grind out a rectangular hole to take the substrate, or simply remove the raised prongs in the bait receptacle (top image). The first method is the most secure, but the second seems to work fine.

  • Impregnate the substrates with the lure
    Place the substrates in a pool of the lure liquid (do it in sealed contained unless you want the house smelling of chocolate/peanut butter/salmon). I warm the liquid on the hot water tank to lower the viscosity and speed things up. After an hour or two you will have a set of perfect lure impregnated terracotta substrates ready for use. Press the substrate into the paddle and your are ready to go. Yay! That wasn’t so difficult was it?

Do they work?
There is some solid evidence out there that they do. I have a few rats that would certainly agree - if they could. I have been using a chocolate Connovation lure. So far the catch rate between the terracotta lures and my standard lure (Nutella) has been pretty similar, but too early to make a definitive judgement. The lures are certainly very robust, unaffected by ants and won’t go mouldy. You can also get a huge range of scents, however without better data it is difficult to judge whether they are effective or not.

The lure liquids themselves are (in my view) expensive, however you actually use very little to impregnate the tiles substrates and the lures (apparently) remain effective for at least three months in the field without re-impregnation. There are even some reports that they become more attractive over time (I will provide links if anyone is interested).

That’s it for me, going out to check the traps!

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As a lure for 200’s might it work to grind up the terra-cotta, wrap and tie that with a piece of cotton, to make a small ball and soak those with cheaper, but hopefully just as effective scents. (Might chalk work the same - in the Victors too?) I’d like to try cod liver oil as one fluid.

Are you familiar with this study?https://www.nature.com/articles/s41598-018-30953-1
Single compounds elicit complex behavioral responses in wild, free-ranging rats.

It concludes with five chemical compounds that rats prefer more than peanut butter.
“This strongly suggests that isopentanol, 1-hexanol, acetoin, isobutyl acetate and 2-methylbutyl acetate may be important communicatory signals or cues for rats.”

Acetoin, apparently is a food additive, as well as a vaping flavour. I tried a few vape shops with no success. Do you (or anybody) know where it might be purchased? Or might any of those other compounds be available (and cheap) under a different name?

Just bought some salmon flavoured ones to try out in SA2s. Had seen references to them before but didn’t know what they were. If these are any good at all at saying here kitty kitty I’ll try making more.

The idea of the terracotta substrate is to have a robust porous material - so I wouldn’t grind it up! I would just use a broken shard of the pot and soak it in a scent, or Connovation lure. Easy as. You might find other scents are effective, but the Connovation lure is more like an oil which releases slowly from the terracotta over several months. Boffa Miskal have done some real science on them. Not all scents are created equal.

Chalk - chalk sticks are made from an extruded mix of calcium carbonate and clay. I am not sure how porous they are. Worth a try certainly. Natural mineral chalk is porous and might work well. Not sure what the advantage is over a terracotta pot. How about using NZ pumice or scoria? I find the terracotta very cheap and easy to use, but I am sure there are many other options, Nara uses a polymer substrate - that is not easy to replicate.

Cod liver oil - good idea, I may try this too. However, the oil is likely to go rancid over time. I am not sure it would be easy to re-use the substrate after that.

I will look at the article. Sounds very interesting. As an ex-research scientist I think these substances are most likely sourced from chemical suppliers e.g. https://www.sigmaaldrich.com/catalog/search?term=isopentanol&interface=All&N=0. Apparently the food industry uses this one to confer banana flavours. I expect Connovation lures are based on similar chemicals. Remind me not to have banana flavoured foods! I found this supplier, I am sure there are many others:

http://www.cakestuff.co.nz/store/oil-flavours-baking-emulsions/banana-oil-flavour-1-oz

Not that cheap for the volume. Probably highly concentrated.

Strangely enough (unllike others) I have never had that much success with peanut butter, but nutella works fantastically. I speculate there are strong differences in the preferences of rats depending the abundance of local food sources.

As I mentioned previously, one uses very little of the Connovation lure, so while the initial cost is high, it might last a very long time - perhaps we could find a couple of people to share a bottle. Are you in the Wellington area?

When you say you have “bought some salmon flavoured ones” - do you mean food additives? Let me know how they go :slight_smile:

My chocolate Connovation lure is going brilliantly so far. Photo below for the sceptics (this was from today). I have had regular catches and no ants, no mould, no stealing, no loss during the strike, and no need to re-bait. Makes me wonder why I bother with food lures! Having said that, I think a diversity of flavours, food types and traps is a good approach to cover different rat preferences.

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On an old thread, somebody was having good results with Worchestshire sauce. It contains sugar and molasses, anchovies, salt, fruit pulp, and garlic and onions, so it has a good cocktail of lures in it. It also contains 2 types of vinegar, which some people say repels rats, but, if that’s true, the amounts may be too low for it to work. A spritz of it inside a trap, or in the general area, might be a good curiosity lure. A PB and WS mixture might be effective, because it would prevent the PB from going stale, and the salt and sugar might reduce the speed with which it grows mold. It’s also possible that insects aren’t fond of it.

This is very interesting for me. I have successfully been using a line of about 30 boxed Victor snap traps for over 10 years. I have caught close to 700 rats in that time, nearly all using peanut butter as the lure. Unfortunately in the last year I have started to catch rifleman (one of the main reasons for rat trapping). It seems that the rifleman numbers have increased to such an extent that they are now foraging on the ground (never previously the case - they had always previously foraged in the kanuka canopy). Rifleman love pastes (previous experience of them removing all the paste from around Feratox lures) so I wanted to get away from anything that they could actually eat. It may be that this terracotta approach could resolve the bycatch problem. I’ll experiment…

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That’s rather unfortunate but useful to hear about the riflemen. The terracotta blocks with a chocolate lure continue to work very well for me. There are many other varieties of lures available (such as peanut butter) should that would work better for you. Strangely peanut butter bait doesn’t work for me, which is interesting in itself, and begs the question whether we should tailor the lure/bait to individual rat populations.

It will be very interesting to hear how it goes - by all means contact me if you need any more information.

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Hi Possums_End, are all 30 traps in locations the rifleman might enter them? or just some? and could some of your Victor traps be replaced by doc 200s? oh, what part of the country are you in? cheers, Tony

Hi Tony,

I am on the Otago Peninsula, near Dunedin.

Rifleman are throughout the 20ha of regenerating, kanuka dominated bush. 17 successful nests in boxes this year, across 2 broods. 30 individuals counted during one count this autumn.

I also run a variety of DOC traps and A24s. The Victor snap traps would typically out catch rats in the DOC traps by about 3 to 1. Interestingly, since I have withdrawn the Victors the DOC traps have improved their catch rate. I also pulse toxins - typically DoubleTap - in 30 odd bait stations whenever I feel that rats or mice are getting out of hand.

I will give the terracotta lures in Victor traps a go and see if I can bring my numbers up. Usually on 60 by this time of year, currently at 50.

Best wishes

Shaun

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