Hi. I am targeting possums in the Pelorus Sound using cyanide distributed via a series of tree mounted Romark bait stations, approx. 1.5m above ground, with a mix of peanut butter and jam baits. I’ve got possum numbers around the line down ok however most of the baits are now being taken without any sign of kills under the traps. My guess it that rats are taking the lure and baits, with typical size cyanide baits not containing enough chemical to kill the rats (they need to eat a massive dose for it to be toxic) - but its killing the possums outright. I caught a lot of rats with Victor spring traps nailed to the tree beside each Romark station however decided that these are likely to be snapping shut/spooking possums which are the main target at the moment, so have now removed the Victor traps.
Anyone had experience with this or any clever ideas - I’m thinking I’m going to have to go for box traps for the rats…not easy in that territory
Were you catching mostly ship rats or Norway rats in your traps?
I’m wondering if bait stations at/near ground level would be an option for your project? If so, you could try an additional possum-excluding station at ground level with a rat-targeting toxin inside, and perhaps the rats would find and eat that first before going after your possum baits.
Alternatively, D-rat traps are more expensive than Victors, but can be tree-mounted and have an excluder shroud that would reduce the likelihood of possums setting them off (at least on the regular/rat setting, on sensitive/mouse they go off if jostled). As you’ll see on other posts, not everyone likes them, but if box traps aren’t a good option for your site, you could test out a couple and see if they work for you.
Curious. What cyanide bait are you using? Feratox pellets?
Hi attached is the paper for some work I did back in 2019, the Romarks worked well and we continue to use them for possum control and as long as they are set up well ship Rats will not get the feratox, Norway rats are a question mark as no areas I do pest control have Norway rats in any numbers
In the photo you will notice the baffle in the front of the philproof which I developed earlier, the baffle reduced the amount of bait a possum can take from the large philproof station to about 5% most of which was taken by smaller backrider possums.
The idea being possums are attracted to the scent of pindone in bait stations, they can’t get the pindone so turn to the romarks, Ship rats can’t get in the Romarks so are happy to munch away on the pindone, works really well.
I developed another system later where you just use a piece of .5 mm tie wire and hang feratox Bio bags from branches, high enough that a rats can’t get them but easy for a possum to feed, also works great, where that file is eludes me at the moment when I find it I will post it
romark trial.pdf (392.6 KB)
Hi I found the other paper on suspending feratox Bio bags, years since I have read this and I should revise it, The photo of possum taking the bags looks to be the first trial where bags were higher but later I lowered them to 500 mm which is what is in the paper. A nice feature of suspending Bio bags is that they flutter in the breeze providing a visual attractant for the possum
also a few years later I did away with the steel bracket on the tree and for one of operations easier to just hang the wire from branches making sure there is no close foliage a rat can use.
If you have Norway rats then this could be an option worth trying as while they are bigger and can reach higher they are less nimble.
still hundreds of video on my computer so possums and ship rats at both these and the Romarks and baffled bait stations
cheers
Hi a couple of other points on cyanide in Feratox form. In my experience you do not tend to kill many rats with it
A couple of points on cyanide in feratox form I find you do not kill many rats, if rats can get to the feratox like when in a philproof bait station with pindone they tend to lick off the sugar coating then drop the whole now white feratox pellet on the ground, so have a look on the ground and bury any you find, black fine lines on feratox indicates it is degrading and leaking so don’t play around with it.
feratox will get about 70 - 75% of possums one problem is that it is naturally occurring in some plants so some animals will avoid it.
As a suggestion why don’t you throw a few possums traps in the mix sentinel or flipping timmy which will show what you still have around plus maybe get some of the feratox shy possums
In tips tricky there is a method for making the sentinel user friendly
If you have the romarks 1.5 off the ground I guess you have Weka, from memory traps need to be about 800 off the ground for Weka, I run my Sentinels 1.1 m off the ground anyway as it a nice height to set them
cheers
Thanks Christina for your response and suggestion - the rats are norway rats, we had a real plague of them a couple of years ago - I will try some ground bait stations and maybe some D traps and see if that works.
Rgds
Thanks for your response and the papers Dave - I will go through them as I have struggled to get info on rats with cyanide. I have been using a mix of feratox pellets and cyanide paste in good size bait form - the baits are killing the possums but I haven’t found any rat carcasses at all (we don’t have a big weka population but that could be acounting for some carcasses). I have also used chew bags and they seemed to work well enough but not on rats.
I used pindone on an earlier forestry project and that was ok apart from the huge volumes the possums went through - modified the approach to include cyanide paste and feratox pellets mixed with the pindone pellets and that seemed to improve the strike rate - although I’m guessing as pindone doesn’t enable a carcase count… pindone might be a cost-effective way to go for ground bait stations and I’ll give that a go…
many thanks
Ant
Agree on the earlier post regarding feratox and rats. They lick the spheres clean and drop them without breaking. There’s plenty of toxin in the pellet to kill a rat; they just don’t break them.