Trapping Rats - Natural Food(s) vs. Food Group Lures Experiment

[willowflat_warrior]

I run a number of traps on my neighbour’s property, which has 4 large walnuts trees on it, all of which are fruiting. I’ve always wondered if it is possible to still trap rats when they have an abundant, natural supply of a high-quality food available to them. Should I disarm my traps until the walnuts have stopped fruiting, or are there lures that I can temporarily switch to that will still trap rats?

With walnuts, rats have a food that is especially attractive to them due to its high fat and protein content. Walnuts’ fat content is approx. 65g per 100g and protein approx. 15g per 100g. Peanuts have a fat content of 49g per 100g and 26g per 100g, by comparison.

Could lures from other food groups be an effective way to maintain trap interaction rates when seasonal food sources compete with your traps?

• Lures with a high sugar content, like dried fruits, hard candies, or chocolate.
• Lures that contain salt.
• Flesh and/or fish lures rich in minerals.
• Foods that are high in fibre, like cereals, fruits, and vegetables.
• A lure that contains high levels of different kinds of fat than walnuts do.
  Walnuts contain polyunsaturated fats and Omega-3 fatty acids. Tallow, however, is 100% fat - 50% saturated, 45% unsaturated, and 5% polyunsaturated. If you can find tallow at a grocery store or butchers, I highly recommend trying it.

Tomorrow, I’m going to put some tunnels underneath a pair of the walnut trees on my neighbour’s property, to try and find out if lures from other food groups are ignored by rats focused on eating the walnuts. I’m going to put a variety of lures from different food groups inside my DoC tunnels and inside the bait cups of unarmed snap traps to see what happens.

If any trappers out there are able to join me in conducting a similar experiment, I’d love to compare our results. The food that the rats are focusing on doesn’t have to be walnuts, but it’s one of the best foods to test against, because they’re one of rats’ favourite foods.

Cheers.

[mindie]

Hi WFW – a good question that I often contend with when kill numbers drop to low levels – maybe they are on local foods?
I live in a rural/residential subdivision of 30 - 1 acre sections – surrounded by a large kiwifruit orchard, a small untidy avocado orchard and the harbour estuary.
Down each side of the subdivision is a walking track adjoining the orchards – but for some reason the developer planted about 20 walnut trees and about 20 chestnut trees between the track and the orchards – I hate both walnut and chestnut trees – walnut fruits can roll your ankle if you tread on them and chestnut burrs that will spike anything – human or animal that walks on them – vet surgery to remove chestnut burr spikes from a dog foot is expensive – I know!
I trap rats regularly beside the walnut trees – currently with lots of fruit on the ground – peanut butter is working well on a couple of Victor pros and rats keep coming
I did trap rats for two seasons when the chestnuts were on the ground – I got about fifty rats each season before I wiped them out. I was using six core flute boxes with black plastic snap traps – Kness and Chinese copies. It only took a few weeks to wipe them out – on one site I had a couple of boxes with a heap of dead rats chucked on the ground a few meters away in amongst the burrs and trash. Peanut butter on the traps and hundreds of fresh chestnuts on the ground to choose from – they kept coming to the traps until they were wiped out. Due to a property change, the orchard owner took over the chestnut area so I stopped trapping. I walked around there recently and saw rats hopping around in broad daylight. The adjacent house owner is very rich and has two Bengal Tiger cats for rat control – it seems to work as I saw a few partly eaten rat bodies.
My advice with your walnut trees is keep on trapping – mix up the lure a bit – peanut butter or meat lovers will work well with walnuts.
Farmlands have run out of meat lovers so I couldn’t stock up today.
Goodnature did a survey on my recent purchase of ten sachets – I told them my negative thoughts about chocolate, and my positive thoughts about meat lovers and possum paste – Thomas came back and told me they give trappers choices – what works for one may not work for others - but they will not promote possum paste for rats as it has not been tested – after ten years - wow!
Chestnut rats

Walnut rat

[andrea_shepherd]

Hi Willowflat warrior, an excellent test. Looking forward to seeing your results.

[willowflat_warrior]

As a rule, rat kills drop due to their population density and/or food supplies.

If you’ve managed to significantly reduce the rat population within your trapping range(s), the rat-to-trap ratio has decreased, so interaction rates will be low.

Rat kills will/should drop when one or more natural food sources are available, because the edible lures in your traps should become less attractive, by comparison. I doubt that many rats would pass up fruit, seeds, eggs, and chicks for week-old PB, for example. Also, trap-wary individuals aren’t going to risk eating out of a trap, when there’s plenty of food around.

Once the natural food supply starts to dwindle, rats will return to searching all of their territory for food, instead of repeatedly visiting a small area, so interaction rates will start to increase. After feasting on a natural food source, small rats may have grown enough to be killed by snap traps, so a spike in kills may occur for that reason.

Wow, those are excellent rat totals when there is an abundance of high-quality food on the ground! Licking up PB is a lot easier than chewing through a hard shell, so that may have been what made the PB so effective. Would walnut or chestnut butter have been even more effective than the PB?

Your results with PB, another plant high in fat and protein, doesn’t bode well for my hypothesis! I wish you were still at that place, so that you could try a different lure this year. Nutella? You’d still be using a lure containing a nut, but would the chocolate make much difference? I would expect it to, but I had assumed that PB would be a poor rat lure when similar foods were available, so…

Did the orchard owner object to you continuing to trap? Do they know about the rats in daylight? If I owned an orchard and a keen trapper lived in the area, I’d buy them supplies and pay them a bounty! Rats go crazy for avocados, so unless they already have a proper pest control plan in place, they’re an idiot!

I have killed rats using cracked walnuts in DoC tunnels when there were walnuts on the ground a short distance away. The stronger smell of the exposed walnuts, plus the convenience of not having to break open the walnuts, is probably what lured in the rats.

I’ve read numerous times that placing traps on rat runways leading to a natural food source is one of the best ways to trap them, because they can’t avoid encountering the lure(s) that you’re using. Would traps between the trees be more effective than traps by the trees? On their way to the trees, what % of the rats would stop by for an appetizer of PB, etc.? What % would have some PB for dessert on their way home to the nest?

Occasionally, when things are slow, I put some GN cinnamon possum lure in my snap traps, and I have trapped both rat species and several weasels with it. I don’t know if the weasels were lured by the GN possum lure or rodent activity, but it is the kind of scent that might pique their curiosity.

I’ve written numerous times how big a fan I am of GN’s Meat Lovers’ lure. I guess I’m not alone!

I just wrote a post about using solid lures in snap traps. It sounds like you’re in a good position to harvest data. Normally, I would be, too, but I’m recovering from a groin injury, so I’ve had to ramp down my trapping. Luckily, I have a few snap traps in excellent spots, so I can still keep the numbers down a bit.

Thanks for the reply and the photos. I’ve had the chestnut burrs stuck on my shoelaces, which is a delight.

[willowflat_warrior]

Thanks for the encouragement, Andrea.

I’m recovering from a groin injury, so I’m not checking my traps as often as I normally would, and I’m only checking the ones on even ground.
This is one of the reasons why I’ve invited other trappers to join the experiment or to share their experiences.

The rat populations here are quite low, too, so it would take me some time to collect enough data to make any conclusions.

Cheers.

[andrea_shepherd]

Injuries are so annoying when they slow us from doing what we love. Hoping your recovery is steady.
You may be interested in the survey Marc Daglish is putting together. (also on the predator free discussion site). At moment in it’s draft form, he’s looking for feedback on questions to ask. Topic is lures/ trap types/terrain/ vegetation/altitude, what works where and when.

[Springfield_trap_lib]

I pack my traps with what ever if fruiting in my garden.

[willowflat_warrior]

Do you harvest the fruit during the day so that the rats have less fruit to eat at night?
If a trapper only had 1 or 2 fruit/nut trees in their back yard, they could give it a go.

If I was able to harvest a large % of the walnuts under my neighbour’s trees, for example, I would expect the rats to enter my DoC tunnels to get them. If 5 rats normally had enough walnuts to get their fill every night, but there was only enough for 2 rats after a harvest late in the afternoon, the dominant rats would claim the walnuts on the ground, while the subordinate rats would probably explore my DoC tunnels.

Do your “fruits” include veges?
If rats like veges like carrots or spuds, they’d be great winter lures, because they should last for a long time, I’d imagine.
The only downside to using veges, would be that mustelids wouldn’t be interested in them, but if there’s enough rodent activity, they might have a poke around.

One lure that I think could be very effective is sweet corn, but the risk of bird by-kill would increase significantly.

Cheers.

[willowflat_warrior]

I’m already signed up for the survey. I hope that some interesting trends emerge.

[mindie]

Hi WfW – thanks for your interesting post – you have got me intrigued about local food supplies and the chestnut tree patch. I figured that there would still be a couple of my wood trap boxes under the chestnuts – so I scrambled around under the trees and trash and found them – one with a dry rat carcase and one with a clean trap. I decided to reset them in an open area where there was less risk of me slipping on slopes with burrs. There are thousands of chestnuts on the ground and more falling all the time. I got my wife to come and give me some moral support – she brought the kitchen nut cracker so we smashed some chestnuts and stuffed them in the box along with a plastic trap and fresh PICs peanut butter. I cleared the ground in the trap area so rats wouldn’t get spikes in their feet!. Just one small area of about 150m *50m of chestnut paradise.
We also went down the other track to the walnut trees. I had changed out the old Victor pros for clean plastic traps and peanut butter – but after two nights the traps were not tripped but the peanut butter was gone – some evidence of large slimy slugs on the traps and boxes. So we changed back to the old Victor pros, slug bait, peanut butter and we tried and failed to smash some fresh walnuts. So we threw in some freshly smashed chestnuts in the boxes.
Back this morning to the chestnut patch – all as we left it yesterday – a big disappointment. Back to the walnut patch – only one Victor pro tripped and a silly mouse was the victim. Amazing how the Victor pro will trip up a mouse.
On the way to the chestnut patch – I saw a neighbour who had just lost her husband and was waiting for me to reset four box traps around her section – so two around the compost bins, one under the apple tree and one under the pear tree – both with lots of fallen fruit on the ground – some chewed – maybe rats or birds. So interesting to check there tomorrow.

[willowflat_warrior]

Whatever gets trappers thinking about how their techniques and lures is a great thing, so I’m glad that I’ve inspired you to do some scouting and experimenting. I’ve read a lot of articles and studies about trapping, and I’m always trying new things, hoping to discover a fresh approach that increases kill rates.

It was probably a good idea to reposition your traps, because wet leaves and sloping land is a bad combo, especially if there are plenty of nuts around to step on.

The only slug that disturbs my traps is the leopard slug, which can grow large enough to spring my mouse traps! This doesn’t happen very often, though. Other slugs and snails show zero interest in my traps, regardless of the lure(s) used.

Regarding walnuts, I’ve found that they can often be crushed on top of the timber lids of snap trap or DoC tunnels, using a gloved hand or by crushing them with my shoe. A small hammer or mallet would come in handy, because nutcrackers aren’t necessarily easy to use, and I’ve broken several of them.

Even a small crack should make a walnut way easier for rats to smell, so you don’t actually need to break the whole shell. With a crack, less of the walnut will be exposed to the elements, too. Unfortunately, I’ve found that walnuts tend to grow a fuzzy mold fairly quickly when it’s humid or damp. In winter, I leave walnuts intact, so that they remain attractive for as long as possible. Even through the shells, the fatty smell of nuts is easily detected. Unlike soft lures, you don’t have to worry about mice, insects, or slugs and snails, disturbing your lures. I have yet to find a single nut that mice have attempted to nibble through.

Usually, it’s easy to tell what animal has been eating fruit on the ground, because birds peck holes in the fruit, whereas rats use their teeth. With feijoas, the toothmarks that rats leave is easy to see. If the fruit isn’t ripe enough for their liking, there will be a rectangular patch that corresponds to the height of the rats’ jaws.

I’d collect some of the chestnuts and walnuts for future use. When food supplies get low over the next few months, rats will be very attracted to the nuts, which they know are a good source of food and they’re also appealing because they’re a food that they can take back to their nest. One technique that can be used with snap traps and whole nuts, is to put the nut behind the trap. In order to get to the nut, rats have to cross the armed trap.

This technique is more effective, more humane, and more user-friendly, if the traps are mounted to the base of tunnels. You don’t have to worry about traps getting damaged when they go off inside tunnels and injured rats can’t drag the trap to the front of the tunnel, where pets can scavenge carcasses and/or damage traps and tunnels. Traps are more stable when they’re mounted, so small disturbances are less likely to set off traps.

If you ever decided to make your own snap trap tunnels, attach the lids with hinges or a nail in one corner and a screw in the other, allowing the lid to spin out of your way. Checking traps is way easier and faster this way, and it can be difficult to push traps on a sensitive setting into the tunnel without springing them.

I hope that you’ve killed a few rodents since you posted. I trapped 3 ship rats yesterday, and I wouldn’t be surprised to find at least 1 kill today, because we had a cold, rainy night.

If you have a garage or shed, I highly recommend placing a snap trap on top of a workbench or large shelf, because they’ve been absolutely lethal to ship rats. Place another tunnel on the ground, to kill ship rats that aren’t climbing and to kill brown/Norway rats, which rarely climb.

Cheers.

[mindie]

Another really interesting post WfW – thanks, I always learn something
Not much to report on rat food – I put a third box under the chestnut trees – checked them yesterday and no trap action - just more chestnuts falling – must have been twenty stacked up beside one box – heaps of peanut butter in the box and on the trap – so they are either eating nuts, or may have been poisoned by the kiwifruit orchard operator – the orchard wraps around the top of the chestnuts
A bit different on the other track beside the chestnut trees – a mouse in one box every day and one rat still keen on PB – I put a few ton op of the box and they were gone next day – a local cat or hungry rat.
I have a couple of old victors under a hedge a bit further around the street – 20m away from avocado trees laden with fruit – I had heaps of peanut butter on the traps and on the ramps for a couple of weeks and yesterday I got a Norway – but he is still on the ground under the trap so he may not have any mates looking for a feed of red meat.
So - are local fruits keeping the rats satisfied – chestnuts probably, walnuts probably, avocado fruit on the trees or on the ground possibly
I have been making boxes for many years – started off with a swinging top but found it too easy to trip the trap sitting it down on the box floor – so I changed to a drop down mesh entry and a coreflute slider for the trap – I like sliders.
No rats in my shed and not many around the section at present – just hedgehogs – four in the last week – not a lot of fun getting them out of a fenn6 and worse out of a walk through doc200 where they are always still alive. Hedgehogs are coming back big time around here as PFBOP only provided snap trap boxes.

[willowflat_warrior]

Even getting mice is impressive, considering the fact that there are nuts and avocados around.

If the avocados are up for grabs, they’re definitely a lure to consider using inside your DOC tunnels. I’ve trapped a few rats using avo pits in the egg holders in my DOC tunnels.

I don’t trap many hedgehogs, so I’ve reserved one DOC tunnel for them, which has 10x10cm baffle entrances. My DOC 200’s tare set at 80g, so when hedgehogs spring them, the kill bar strikes them on the head. You can buy sets of small weights to change the sensitivity of your DOC series traps. There are some videos on Youtube that show you how to do it, if you’re interested in trying it.

Cheers.

[mindie]

A couple of traps on the edge of rough ground, avocados, rock hard ugly walnuts and a couple of hundred metres to the estuary – I just never know what might show up. I seem to have cleaned out the mice, so just ants keep cleaning up the peanut butter each day – but I persist with heaps more PB.
Yesterday we got an old Norway – he had lost half his tail so he should have known more about a rusty old Victor with PB. So up on top of the box to attract his mate. My wife took the dog for a walk last night and sloshed some possum paste on the trap. I checked this morning and find the rat had been dragged off the box and his mate had bled out just behind the kill bar.
Just another example of Norways hunting in pairs – so many times they follow on and die in the same box. PFBOP system shows I have logged 105 kills at this site in a bit over six years. In excess of 400 for the street residents.
I am not sure rats concentrate on local food such as the trees laden with avocados – they are likely on the move and these two might have come from anywhere – maybe muddy feet around the estuary. Just set the trap, keep it baited and wait with interest!

[willowflat_warrior]

It’s good to hear that you’re still getting a few rats, despite the delicacies in the area. PB’s always effective, to some degree, isn’t it?
In wet weather, I switch to tallow and Goodnature lures to keep the mold at bay.

I’ve found a number of rats with damaged tails, all of which had ragged, tooth-like scars.
I’ve never trapped a rat by the tail, fortunately.

Your wife giving the trap a splash of possum lure was a good idea, because it would have been very easy for rats to detect it when it’s that fresh, especially from a distance. I try to lure my traps later in the day, because it takes longer for the scent of most lures to weaken. It’s a good way to limit mouse interference, too, because they don’t have much time to raid traps before rats turn up.

Where is that productive trap sited? It could be on or near a travel route, AKA runway.
Is there just one trap there? If you have a few underperforming traps around, it might be worth it to move them to that site for a while, to find out how many rats are in the area.

I should have worded my post differently, emphasizing that I was primarily interested in wild rat behaviour. Urban rats have so many sources of food available to them, year-round, that visiting a walnut or avocado tree is a treat, not a potential necessity.

Thus far, my experiment at the walnut trees has been a total failure. The PB and tallow have both gone untouched. I don’t know how large a role neophobia is playing, though, so there may be rats tempted to try the lures, but too wary to enter the tunnels. Judging by the small number of walnuts being eaten, I think that rat numbers are also lower than normal. It was a spur of the moment experiment, so I wasn’t expecting to actually reach a conclusion, anyways.

Your data collection helps, especially since the rats there have several very attractive foods available to them right now. The fact that you’re still trapping some with PB, shows that at least some of the rats in your area aren’t completely focused on the nuts and avocados.

I’ll keep you posted if I finally get any results.

Cheers.