If dogs and feral cats aren’t a problem scavening dead possums, leave their bodies for 1-2 nights at the trap where they were killed. Apparently, the presence of another possum at a trap increases the chances of them exploring the trap. Keep killing the bastards!
All hail cinnamon!
What have your results been lately?
I hope that the cinnamon has continued to work.
Any kills with the highly-modified Snap-E?
Have the T-Rex’s arrived, yet?
Cheers.
I’ve been away for a few days so haven’t checked the rat traps but nothing in the possum traps although there were signs of new possum damage around the rat traps a few days ago when I last looked. The T-Rexes have arrived and are set up, but again haven’t been around to check them yet.
The trail cam has been a bit of a disappointment, the lens is too long for closeup stuff unless all you need to cover is a very narrow field of view, but according to other reviews too short for field work where you’ve got deer some way off, it seems to be a bit of an unhappy medium. I need to check the footage again tomorrow but so far the only revelation is that there’s at least one pukeko down there which I’d never seen here before, and neighbours who have been here in some cases over thirty years had never seen either. If I hadn’t seen the video footage I wouldn’t have believed it, I’ve never seen one in at least a 5-10km radius of here.
I guess I asked about your progress (fingers-crossed) too soon. I hope that the T-Rex’s perform well.
Sorry to hear about the trail cam. Buying one is on my to-do list, but there are too many to choose from!
If it’s just the one pukeko, it’s possible that it’s lost.
A magpie, which I think has just reached adulthood, decided to join our family about 10 days ago, but it doesn’t appear to have caused any trouble. It’s getting tamer by the day, only flying off when you get about 4m away. If you couldn’t see it, you wouldn’t know it’s around, because it’s so quiet.
Cheers.
Reviewed the footage and another one of the possums had torn a hole in the mesh and got in, and the following day an army of birds followed. Argh! Unfortunately the camera didn’t catch it in the process of getting in so I’ve relocated it to the other side, which is a bit iffy since I can’t move it back far enough to capture the entire area of interest due to trees. We’ll see.
I’ll make a separate post about the trail cam, or start a thread if there isn’t already one.
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Thoughts on “Making the Better Rat Trap”.
I found this old discussion and thought I would revive it, and give some updates on what my company has been doing
Like many on here I have tried in vain to make the plethora of snap traps do more than create a catchment of wised up rats. All the snap traps have issues - they often catch badly and often just scare off the rats, many with broken limps or a sore nose. My company works in R&D and five years ago we teamed up with a company called TrapTools to “make a better rat trap” - how hard can it be? Well the truth is quite easy - its called poison. But given some don’t want to use it - or cannot around crops or food or pets or whatever second best its called a DOC 150. SO the issue lies not with it being hard to make a better trap but its hard to make it small, light cheap and safe - the wants and desires become exclusive. So still determined to give it ago - five years ago with TrapTools providing engineering and us the field work, this is where we are at:
We started our project investigating what was available. The best of the lot have passed a NAWAC for shiprats and one has passed with mods for Norway rats also. (you can look up NAWAC on line). I’m not convinced by any of those passes since I have bad catches on all.
I define "bad catch " as rats I kill myself next day or find caught by one leg or by a nose. There is a another category we include in our research stats and that is set-off no animal. Some have left a tail or a leg or some fur and some have the trap dragged by cats or themselves to the hole and are gone, some are just set off empty in place. We constantly had around 35 % all traps which were set off - set off empty. With no proof I believe most of those are probably due to missed or pulled free animals, and that was the starting point of our research program. Many “bad catches” and many set offs no animal. The technical issue was to solve this using the standard traps, easy !!
So we set out to do these things systemically:
We treated the project as we would a factory ( we are from science and engineering) - we wanted to improve productivity ( catches) and quality ( how well caught ) and reduce rejects ( misses), with that in mind. We knew we would not find a miracle cure but were looking for a percentage gain in the three criteria.
Stage 1 Test the traps in the lab to see which one we should use of the cheap light traps - we exclude doc traps which work anyhow.
Stage 2 Then we took this one best trap and worked on the box design to:
Reduce the % set offs with no animal.
Improve the catch quality ( we set up criteria for how well caught)
Increase the total number caught.
The “control” or standard setup we used to compare with was a wood rat box set up exactly as we observed being used all over NZ, as made by councils and men sheds in every town.
And five years later and lots of money into injection moulds we have a half reasonable box. We are now working on improving it of course but the first two trials indicate about 30% more rats ( 200% more mice but thats another issue) and sets off no animal down from 35% to 10% of total offs.
Sorry if the numbers are spinning but basically we caught more and missed fewer. The “catch quality” or how we caught them has been harder to analyse, but we are working on the numbers, and waiting on another trial, see below for comments.
The trap we settled on after lab testing was the Victor professional (VP) - it has about 1.5 the whack energy of the next best. The whack is dependant on the amount of energy in the setting and the long 180 degree set of the VP means more potential energy to convert to kinetic energy and so makes it a good trap to work with to to make better. I also quite like the fact is wood and metal - so can be fully recycled - but that was not part of our criteria.
The design of the box was interesting we starting with some old research indicating better entry rates with a certain side entry design so we worked on that to make it fit the bird criterial and to take the swing of the VP. Then we worked on reducing the number of leg forward approaches and restricted the height to stop high head approach.
Anyhow I can go on - but we would like people to try it after the work that has gone in. Potentially this is Mark 1 but we need to sell some before we make all the changes we now want to make. I do not think we can improve the catch rates much more or improve the misses or set offs with no animal. Most of the remaining ones I suspect are animals knocking the box or mice being missed within the swing of the arm. So any changes from here on will be more to do with usability of the box and only small improvements in catch rate or quality can be made…
Last thoughts now the project is over:
If we are going to rely to a degree on mechanical traps to do some of the predator control work we should do our very best to do it well, even if that costs more for the devices. Buying the cheapest is not an ethical choice but we need more data to make informed choices. Rats matter just like cats , and human time counts too plus it there is no point in training up a heap of intelligent rats that will never come back after a bad trap-trip.
We started way back before the project using e-snap and t-rex and when we shifted to the VP we not only had better catch quality and more catches but also we caught smaller rats. I think with little proof that the lower trigger force of the VP means we now catch the juveniles and Kiore. ( I have not included trip forces in this discussion but we lab-measured that too) I am not anti poison, but using this better box system and a few extra traps along streams I am hoping to do my own catchment on Aotea poison free. Or maybe one pulse per year if need be.
I have not mentioned trap maintenance or replacement when old - but that is a real issue, after 8 years crouched down looking into other peoples trap-boxes I can say many (most) don’t oil or replace traps often enough. They are cheap nasty devices but can be improved by care and routine replacement when the springs decay. I know waste is bad but the animals deserve respect.
The issue of “catch quality” was complicated… We have also tested long life lures to end of the lures viable life and then we had a lot of run throughs. These are animals that enter the box and are not focused on the bait since it has lost odour - instead they run for the light at the other end and are caught mostly badly. So for “good quality” catches the baits must be viable. We are running some more trials to see if we have improved catch “quality”. We catch a lot of smaller animals with the VP traps and they are not really made for that - so the problems are not solved yet!
So after all that:
Even if you don’t want a box ( I’m sure you do !) - have a look at www.rattek.com and comment.
- I can take the bad with the good
The other product is a lure out of VUW but thats whole other story, for another long weekend.
Finally - making a better rat trap is not for the faint hearted - I don’t recommend it but Im sure that won’t stop many more people trying - it probably all started with drawings on a cave wall somewhere.
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I’ve used similar enclosed snap traps and they can work well on rats. Non target bird risk is usually low when the entrance size is right and the trap is placed properly, but I’d still be cautious in areas with curious native birds. I’d probably test a few first before deploying 50.