D-Rat Trap - Risk to Birds?

[kahikateatree]

This is the modified D-Rat, one showing the teeth, one showing (sort of) the cut-back trigger plate:

Results so far: Modified D-Rat, one triggered but nothing in it. Snap-E in a tunnel: Triggered and dragged completely out of the tunnel and lying on its side some way away but nothing in it.

I’ve now also modified the tunnel Trap-E in a similar manner to the D-Rat, let’s see how that goes.

And a challenge to any manufacturers or sellers of rat traps who read this: Think you’ve got a rat trap that works? Send me a pair and I’ll see if they can actually catch the rats here.

[kahikateatree]

For lures, I’ve used both aniseed and peanut butter, both do a fine job attracting rats (and birds, watch out for that, the D-Rat is a great bird killer unless you put a screen around it). The problem isn’t attracting them, it’s finding a trap that’ll actually kill them rather than just scare them.

At the moment they’re just really expensive chew cards.

[willowflat_warrior]

I think that the teeth would be more effective if they were in a uniform row, going from 4 to 6. If a rat approaches the trap straight-on, it’s a goner, but there’s a gap on either side big enough that a rat might not make contact with one of the screws.

Also, the screws probably need to be higher. It’s hard to tell from the photos, but when the trap’s set, they look like they’d be level with the treadle. If rats have to lean over the teeth to reach the lure, they’re in a less stable position, especially when they’re clinging on to a post/ramp/trunk. If the teeth are 20-25mm higher than the treadle when the trap is set, your kill-rate should climb significantly.

To aim the rats where you want them, and to limit the risks to birds, you could put in some nails as excluders on either side, and then have a pair of higher screws in the centre (2-2-2). If the gap is only 1" wide, for example, a rat would have little room to move side-to-side, and would have to lean over the teeth. Using nails may be tricky and expensive, though, so it may not be a viable option. A mesh excluder, plus a pair of front teeth, would be good, but it doesn’t sound like an easy job (but you’re clearly bettter with tools than I am!).

I second your challenge to trap designers to put their traps through rigorous trials in urban and wild habitats, to eliminate flaws and provide consumers with expert tips. To save themselves some time, donate some traps to trapping groups and a few field cameras to document what works. The D-Rat might be a good trap in the back of somebody’s shed in the suburbs, killing the occasional easy-to-trap rat, but I’ve seen nothing but bad reviews about its performance in the bush. It’s too late to ask for a refund now, but I think you would have been justified in doing so.

I hope your results improve soon. I’ve done a lot of experimenting with traps and lures, and patience is definitely required!

[kahikateatree]

At the moment it’s very much a trial-and-error thing, I set the teeth low enough that the rats wouldn’t be discouraged from even going near the thing… without a trail camera (still on the way) I can’t tell how they’re interacting with it, but the thinking was that a barbed fence in front of the trap might discourage any interaction. In any case the Trap-E is in a tunnel and the D- Rats are centered on thin poles so the only way to approach is from the front.

In terms of another negative result, the Mitre 10 sharks-mouth style rat trap: Holy **** are these useless! I’ve had really poor results with a similar style for mice so wasn’t expecting much, but these really took the biscuit. A bird had somehow got inside the mesh screen (I still haven’t figured out how, there are no obvious gaps despite an extensive search, I clipped the edges down a bit more just in case) and gone into the trap. I pulled the trap outside the screen by the chain, opened it up, and the bird flew off completely unharmed, not a mark on it and no sign of discomfort. If this leaves a fragile-boned bird completely unharmed it won’t do anything to a much tougher rat.

The only way these things could ever kill a rat is if one has a weak heart and the flap of the trap closing gives it a heart attack.

[willowflat_warrior]

Most rats aren’t deterred by sharp objects, even if the lure is mediocre. I’ve placed sharp tacks at the front of several traps in tunnels, and I haven’t see any evidence that rats are deterred by them, even when the blood of the previous kill is present. Rats deal with sharp items frequently when they travel and eat (twigs, rocks, barbed wire, mesh, thorns/barbs, broken windows), so I doubt that taller screws would deter them, especially since you’re using lures designed to be very appealing to them. Even a low quality lure is an easy meal compared to hunting around for something else.

I think that it would be worth your while to modify 1 of your traps to see what happens.

One of my traps (mounted vertically in a shed) has several very sharp skewers that rats have licked soft lures off of or nibbled firm lures off of, leaving the skewers spotless. The trap has 4 very sharp metal teeth at its base, which they lean over to reach the lure. I killed 3 large brown rats in the trap this winter, which were hard-to-trap problem rats that burrow under the deck. These rats are the smartest of the lot, yet a row of teeth didn’t deter them. I think that rats get cocky once they’ve figured out a trap, so they might not view a few short screws as a risk.

I’ve killed a few adult rats and small rodents that appear to have died from fright, because there have been no signs of injury. On several occasions, rabbits have died without being hit by the rifle or shotgun, so dying from fright is the only logical cause of death.

A had a look at the M10M traps and they looked awful, so I gave them a pass.
The light grey traps are also rubbish.

Trapping is like using 1080 - killing the occasional bird is a low price to pay for killing hundreds of predators. Birds are very good at finding gaps in mesh/chicken wire and netting, so you’re bound to get one now and then. What species was it?

Once again, good luck getting the bastards!
I hope that you find the magic recipe that transforms the D-Rat into a real killer.

Happy New Year!

[kahikateatree]

So I’ve modded the Snap-E in the tunnel to put the screws all the way through. I really, really need that trail cam to figure out what’s going on here though, got down there today and the tunnel trap was triggered with the tunnel flipped on its back and the trap some way away. This is the setup (tunnel upside down to allow a view inside):

The only way I can explain this is if a possum got inside the mesh and pulled the setup apart, otherwise a rat would have had to go up the tunnel, trigger the trap, flip the tunnel over, and then pull the trap away. I left a bait bar off one of the feed stations, now with a trap inside it, leaning against one of the posts and this sure looks like rats rather than a possum (note also the half-chewed scraps that have fallen to the ground next to it):

I’ve also started a new thread on trap types and what works and what doesn’t, since there’s a lot of stuff that may be of interest to others hiding in this one.

[kahikateatree]

The birds (one killed by the D-Rat right at the start, one annoyed by the flap-trap) were both thrushes, there’s a ton of them in the garden. I set up a bird feeder a few metres from the trees in the hope the birds would go for that instead of the fruit and refill it almost daily so they’re certainly taking advantage of it.

Will see how the modded Snap-E goes tomorrow.

[Wak_Trapper]

Similar experience with the D-Rat trap, the only I got them to work was find a tree that is on 30 degree angle and put a bait trail leading up to the trap.

There are still not as effective as a Victor trap in a tunnel (based on catch rates), but you catch much more than having them vertical. I have only caught one rat on vertical placement.

Thanks…Gary

[kahikateatree]

Ah, thanks for that! Based on willowflat_warrior’s comments I’ve moved two of the D-Rats to posts whacked in at about 45 degrees with a bait trail leading up to them, but after multiple mis-fires, meaning triggerings without catching anything, the rats appear to have learned to avoid them, the bait trail gets eaten but the trap is untouched.

I’ve now modified a second Snap-E and put it into a bait station to see if that helps, the other modified one in the tunnel is still being triggered every night to no effect, it ends up outside the tunnel with the bait gone and nothing in it.

I’m still puzzled how rats are managing to do that, in one particular case they flipped the tunnel over and moved the trap some way away from it, but it’s almost certainly rats and not possums since the Timms is untouched and the rat poison from the bait station which I’d leaned against a post is disappearing at a great rate, this is one night’s worth (compare to the previous photo):

Maybe that’s the trick, frighten them with traps that barely work and they’ll happily devour the poison next to them.

[kahikateatree]

And another round of traps triggered with nothing in them, left it set inside the tunnel, in the morning it’s triggered, outside the tunnel, and with the bait gone:

This is the modified-with-teeth one, not the basic trap. I’ve now got a second trap with the trigger bar cut down even more in the hope that they get far enough in that they trigger the trap once inside the kill zone. The only consolation is that they’re eating the poison moved out of the bait stations at a great rate, it’s almost gone now so the poison at least should do something to the population.

[willowflat_warrior]

I think the reason why the modified Snap-E isn’t working, is that too much of the treadle was removed when you put the screws in. A rat would have to push on the lip with both paws to put enough pressure on what remains of the treadle, probably. What’s left of the treadle looks really flimsy, so it should break easily. Making a rectangular replacement treadle that just fits within the screw border could work, and if you made the treadle higher than a normal Snap-E one, by 10mm, for example, it should be harder for rats to avoid touching it when they lean in to reach the cup. You could also extend a DIY treadle, making it block off half of the bait cup, which would make it harder for rats (and mice) to eat lures. It would make it harder to get some lures inside the bait cup, but lures like smooth PB, Nutella, and mayo could go in a bottle with a snout and be squeezed inside. How would you make such a treadle? Beats me. Attaching a low-weight excluder of some kind on to an unmodified treadle that partially blocks the cup, might trap a few rats. You could try gluing one on, or for an experiment that doesn’t damage the trap, you might be able to use wire/string/blue-tack/a strong rubber band, to see if it makes a difference. Imagine if a treadle add-on was all it took to get them?

I think that you’ll have to make a row of teeth around the trap, instead of modifying the trap itself. A row of teeth through a wood/plywood base is you best shot.

Buying a T-Rex would be a wise idea. I’ve killed numerous rats with vertical T-Rex’s, so they could save you a lot of time, money, and frustration. They usually cost $10-12. Mine have lasted a long time, so the cost per year of using one is low.
In 2022, I killed 49 rats with my T-Rex’s and 7 with my Snap-E’s. Almost all of the lure-consumption out of the T-Rex’s was from mice, but rats regularly left the Snap-E’s spotless (droppings evidence and teethmarks). Only a handful of times did T-Rex’s go off without catching rats or small rodents, but the ratio of kills to empty traps that had been sprung with Snap-E’s was at least 1:4.

Buying one of these traps might also be worth your while.
Times Up Metal Rat Trap - Household Pest Control | Mitre 10™
With this powerful trap, rats push a solid bait on the skewers as they try to bite into it. They’re useless horizontally, IMO, but they’re great when they’re mounted vertically. Small pieces of pork fat and small pieces of jerky both work really well for brown rats and mustelids, and pieces of dried apricot or other fruits should lure ship rats. It’s also way easier, and safer, to set when it’s mounted vertically. 100% metal, they can last for a long time in harsh conditions.

I’m not a fan of the Victor Pro, but trying one of them vertically would also be worthwhile. Tying a firm lure, like a piece of jerky or apricot on to a Victor treadle would make things harder for rats to eat or steal.

Keep soldiering on - it’s only a matter of time before you’ll be posting pics of kills.

Cheers.

[kahikateatree]

Yeah, it was trial-and-error to try and figure out why they were triggering the trap without getting caught in it while waiting for the trail camera to arrive. Shawn Woods, trap supremo, has a video somewhere in his collection of a rat dropping a stick across a trap to trigger it and then eating the lure, but I haven’t found any traces of something like that, or rat-sized lockpicks or crowbars either, so until I get footage of what’s going on it’ll remain a mystery.

I’ve already got some T-Rexes on order, however due to the long holiday shutdown I don’t know when they’ll arrive.

In terms of modifying the treadle, that’s going to be tricky, problem is that the PE/PP that the traps are made of is essentially impossible to glue to, particularly in this case where it’ll need to withstand mechanical shock (you can get pricey plastic glue that supposedly works on PE/PP but it doesn’t actually work very well on those and probably won’t withstand a trap activation). Possibly use some M3 304 stainless bolts to attach a modified treadle to the back of the cut-back existing one.

In any case the problem isn’t rats not triggering it, it’s triggering it without being caught, see the previous photo, thus the move to a smaller and smaller treadle in the hope that they can’t trigger it until they’re well inside the kill zone.

[Maybe_It_s_a_Trap]

Grab some Fenns or DOC150 and put these tricky rodents out of their misery once and for all

[willowflat_warrior]

I like the comment about lockpicks and crowbars. It certainly feels like they’re using tools sometimes!

I’ve also had difficulty gluing things to plastic, and drilling isn’t always an option, due to the risk of thin plastic cracking. It’s bloody awkward, but using wire may be required. Tying a piece of a firm lure, like dried fruit, a firm piece of candy, or a piece of jerky, to the front of a T-Rex treadle might be a good thing to try, especially when they’re mounted vertically. Put in in the middle of the treadle, and then a loop from the lip of the hole above the bait cup to the front. In order to sink their teeth in, rats will have to put a decent amount of pressure on the treadle with their snout and/or paws. Because the lures are tough, mice, insects, and invertebrates will take a long time to eat it.

Jerky would be a good, hard-to-eat lure. In theory, it should be more effective at trapping brown rats, given their dietary preference for meat, but I’ve killed at least 50 ship rats using Goodnature’s Blood Lure (but it’s probably a much higher number) in my snap-traps, so firm, dried fruit, or candy may not be necessary (but rotating lures is a good technique). Goodnature’s lures aren’t eaten by ants here, which is a huge plus, and I’ve never found any evidence that larger insects or invertebrates eat it.

Dried fruit, like apricot, should be effective, and licorice All-Sorts cut in half, to reduce their weight and size to attach them to a treadle. If they eat All-Sorts, it should take insects quite a while to ruin them. There are quite a few gummy and hard candies that should work, instead of All-Sorts. A wide range of animals like anise, the substance in licorice that gives it its distinctive smell. Dried apricots should be more attractive to insects, but they’ll last a while, compared to soft lures like PB, Nutella, etc.

Regarding licorice as a lure, I knew a guy in Southland who used All-Sorts to trap possums, and he racked up impressive totals with it. This poses a problem in terms of possum interference, as do dried apricots, but they can both be used in Timms, and other possum traps with skewers, so placing a possum trap at the base of a trunk/post, or mounted vertically, below a rat trap, would be a good idea. Trapping expert Cam Speedy recommends placing traps targeting different species at the same site, in order to increase interaction-rates.

Once again, good luck! I hope the mini-treadle works.

[kahikateatree]

Three days of nonstop rain may have solved the mystery, or at least, like finding a fish in your beer, provided strong circumstantial evidence for what’s going on: Went down there today in the rain and the two posts I’d whacked into the rock-hard ground to create a 45-degree rat ramp had both been pushed over in the now very-soggy soil. The only explanation I can think of is that a possum walked past the Timms traps and somehow got though the mesh around the trees even though there’s no obvious gap or hole in it (the rain discouraged a lengthy survey). The trail cam arrived earlier today so I’ll be able to confirm tomorrow. In the meantime I’ve rebaited one of the Timms with a cinnamon’d apple and the other with peanut butter just in case it’s more attractive than the same bait in the rat traps.

[willowflat_warrior]

I think you’re right about the poles. I can’t wait to find out what the trail cam shows.

A big advantage that cinnamon-coated apples have, is that rodents rarely eat them. Here, mice and rats nibble them perhaps 1% of the time, and that’s in winter, when their food supplies are low. The one time that a ship rat decided to really sink its teeth into a cinnamon apple, I trapped the bastard. It ranks among the largest ship rats that I’ve ever trapped, so smaller ones might not spring a Timms. You could experiment by changing the sensitivity, to see if medium-sized rats are trappable.
Cinnamon has also kept insects and invertebrates away for me, too.

The problem with using PB is that interference levels should soar, because so many species like it. You could try spraying the PB with white vinegar, because insects and invertebrates dislike the acidity, whereas rats and possums love the smell and taste of vinegar. It just occurred to me that sprinkling some cinnamon on top of the PB might be a good combo. I have to re-lure my possum traps today, so I’ll see what happens.

I’ve killed 3 large brown/Norway rats this year in Timms, once I started using thick pieces of pork fat from the edges of pork steak or a roast. I (very carefully) make an X cut into it, because skewering it on a Timms is impossible without them. Rats and mustelids love fat, so it’s a great lure to use, and its firmness forces rats to really sink their teeth into the fat. Mice and small rats can nibble at it, but they usually only eat a small amount per night. I haven’t trapped a ship rat using pork fat, yet, but it’s possible. I dunk the fat in vinegar for about 5 seconds, because this gives it temporary protection from insects, including blowflies, and mould.

FYI, I learned a few months ago that I’d been luring my Timms incorrectly. I’d been using half a small apple, when I should have been using a thumb-sized piece, and I learned that smaller pieces should be skewered horizontally.

[kahikateatree]

I actually had problems with rats going for the apples previously, every night the Timms had been cleaned out and roughly every second night the entire contents of the possum bait station was removed, which is why I was so sure it was rats again. Since it’s bucketing down again I haven’t done much because the rain is washing everything not under a roof away, got the Timmy on a half-round at 45 degrees which finally makes it possible to arm as easily as the ground-based Timms is, both with well-cinnamoned apples and the trail cam covering the area.

[kahikateatree]

So the amount of circumstantial evidence that the main problem is actually possums just increased quite a bit:

That was with willowflat_warrior’s cinnamon-apple trick, thanks for that! Got it the first night I used cinnamon, this was (presumably) one of the ones that had walked straight past the Timms trap line in the past and got through the mesh cage around the trees to attack them. I assume there’ll be a few more, will be resetting things tonight.

[willowflat_warrior]

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!

[willowflat_warrior]

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.