I have tested the treadle movement of a DOC200 and DOC150 and found that the DOC200 has a much larger displacement, even though they are calibrated to the same trip-weight. I’ve made a video and posted it here: https://youtu.be/1p51jZW52o4
That video also shows a trail camera video of a ship rat escaping from a DOC200 after it had fired off. This is similar to one that Tom Agnew ZIP posted recently https://www.youtube.com/watch?v=izyZYX1v6_Q&t=1811s
at about the 30 minute mark in this video.
I wonder if that is leading to pests escaping from the DOC200 more often? I’d be fascinated to hear what other people think of this.
Hi Marcus
always going to be hard to know if more animals escape from a 200 than a 150
I covered the animals not being killed in other stuff I wrote in Tips and Tricks like the covering treadle plates and ramps which we discussed before.
In the papers I have been able to find online with the 200 in the original Nawac testing 15% of animals did not get caught in the trap, changed their mind and left or touched the treadle and changed their mind or the trap went off and they escaped. The most disappointing thing is this was now so many years ago but Landcare, DOC and the manufacture have done nothing to improve the situation. And unfortunatly when the pirate copies of the 200 started they did nothing to improve the faults in the 200 just got them made offshore for a quick buck.
When ZIP tried to make a tunnel with two entrances but one 200 trap ( following on from regional council work in Hawkes bay ) and save the number of escapees they did more testing with Lincoln and had something like 20% of animals not caught
Yet 2050 have already said they will not fund any development of traps unless they are high tech, after more than 20 years in this game I’m of the same opinion as others with better low tech $50 traps they will get 95% of pest animals, but more profit in high tech which groups can’t afford on the scale needed
cheers
Hi I forgot to add that one factor in escapees on 200’s is possibly the vertical opening in the internal mesh, you will see that in the videos the rat is not fully engaged with the trap only part of the body is over the treadle plate. The best practice internal vertical opening could be called restrictive which makes an animal go slower
It is like that because they needed head strikes to get the trap to comply with the NAWAC time to no eye reflex ( death ) . Obviously nobody wants an animal to suffer any longer than absolutely necessary, but one does have to wonder if animals moved freer and were further over the treadle when the trap activated would this reduce the number of escapees ?
I’m NOT in any way suggesting that people should increase the size of internal mesh
cheers
Marcus and I have collected a lot of stats using snap traps also. The worst of them, such as snap have about 30% set offs which I think are mainly escapes. The design encourages front foot to be caught and then pull out broken but escape.
The better one seems to be victor professional but is not good for any small ones or when the bait looses attraction we get run throughs and caught every which way.
Hi Marcus
I don’t have any 150 traps here as I only use 200 and 250’s . I had a quick play and roughly if I take measurements on both a 200 and 250 trap pivot point to sear and pivot to end of treadle then what I get is with a sear set a 1mm which is roughly about right for 80 - 100 g set off weight. Then at the end of the treadle I should have 6.8 mm movement on a 200 and 7 mm on a 250.
I don’t have one so can’t measure a 150 but it would seem funny that your 150 is tripping at 1mm movement in the end of treadle,
Waddington made that video years ago about making traps more sensitive by bending the end of the trigger arm out which makes more of an angle and spring weight would tend to push the arm , more of a hair trigger, but one would think that you should still need the same movement at the end of treadle to allow the sear to go under the arm.
has left me scratching my head,
Hi Dave
I’ve got about 20 DOC150 and 80 BT150 traps in my shed at the moment, all calibrated to 80 grams. Doubtless Conservation switched over to 150s a couple of years ago and although they are a bit more challenging to set up, we are very pleased with their performance. So the average sear height I get from about 6 or them is 0.4 mm
The distance from pivot to sear is 25mm and the distance from pivot to end of treadle is 115mm so the treadle movement to trip the trap should be about 1.8
however there is a small radius on the end of the sear and I suspect that once it has dropped a small amount the trap fires off even though the treadle hasn’t moved the full amount.
Doubtless Conservation has 400 DOC200 and 250 DOC150. The 150s are much more sensitive to bumping off when your rebaiting: you only have to touch them and they go off. Whereas the 200s have quite a wobble before they fire.
I completely agree with you. This is why on the Trap Tools NestGard I made the entry ramp slightly higher than the treadle. My reasoning was that if the pest had to step down onto the treadle then they would be placing more force onto the treadle and have less ability to jump back up.
There are a internal baffles around that are very low so that the pest has to step up onto the treadle. Several times now I have seen hedgehogs get caught by their snout which is underneath the treadle. Two I have found still alive in the trap: snouts under the treadle but held by some spines between the kill bar and treadle.
Hi Marcus
I guess my concern with like you say " only have to touch them and they go off " would be that are they missing catching animals because the animal were not fully engaged with the trap when it went off.
I’m actually looking at some data and traps for a group as when I trolled through their data they have been catching mice in the 250’s, so the first thing I naturally think is a ferret or stoat probably only has to touch the edge of treadle plate and the trap will go off, scare the animal but no catch. One thing I’m looking for in the data is how many times the traps are reported as gone off but NO catch
cheers