My primary traps are the DoC 200 and the T-Rex. I’ve made homemade tunnels for my T-Rex traps out of scrap timber/ply.
I stopped using poison several years ago. There is a lot of wildlife here that is susceptible to primary and secondary poisoning, and I find trapping to be very rewarding.
In my experience, the key to trapping brown rats is to use high-fat lures/baits.This generally applies to meat, but oily fish should also work. Walnuts are another Grade-A rat lure.
-
Firm pieces of white fat, about the size of a large graps, work very well in DoC tunnels. To reduce theft and disturbance, I skewer fat. If you’re using eggs in nail-mounts, an option is to place a piece of fat underneath the egg to secure it.
-
The semi-solid white fat from frying and roasting is highly-effective as snap-trap bait.
In DoC tunnels, you can put fat on a piece of cardboard/bottlecap/lid, and dispose of them when the fat is gone, or is getting too old. This keeps the tunnel clean, which is important, because fat is difficult to clean off of wood. A tunnel contaminated by rancid fat is practically useless until it’s cleaned, because the smell is a deterrent. -
If you’re operating a large number of traps, you can put a portion of fat on the middle of the treadle (about 1 tsp). A small spray bottle of white vinegar, some paper towels, and your DoC safety clip, and cleaning treadles is easy. Fat is so attractive to rodents and insects that they will probably do most of the cleaning for you.
-
I’ve found white vinegar to be an excellent tool to extend the field-life of fatty baits. I think that the low pH of vinegar must give bait a temporary acidic shield, which hinders the activity of micro-organisms. If you only check your traps once a week, I highly recommend experimenting with it, giving the entire surface area of the fat a coating.
-
In addition to preserving bait, I’m confident that vinegar makes bait, in general, more attractive. One of the best overall trapping baits is egg mayo. In my experience, the longer mayo is in a trap/tunnel, the less attractive it becomes. I believe that this has to do with the high evaporation-rate of vinegar. Whenever I use mayo, I spray it with vinegar to make the scent last longer.
-
If you trap mice, and have a DoC tunnel that you can check 3-4 times a week, mice are excellent lures. They don’t stay good very long, though, so I keep them inside for a maximum of 2 days. On several occasions, brown rats that weren’t quite heavy enough to set off my DoC 200 treadles, were stripping my tunnels of bait on a nightly basis. Placing a mouse on the treadle added enough weight to the treadle that it trapped them.
-
Goodnature’s Stoat Lure/Blood pre-feed is a good long-lasting lure that’s easy to use and inexpensive. I use it as bait in my snap-traps and tunnels, and it’s a good thing to smear on to a large trap, like a Timms. The only downside, is that blackbirds and song thrushes are attracted to it.
As a rule, rats dislike open spaces, because it makes them susceptible to predators. The only rat that I’ve killed in a relatively-open space was in my roadside tunnel, but it was only about 8m from the edge of the scrub.
I recommend doing the exact opposite of putting a cage in a “nice wide open space”. I’ve had great results in the single and double-set DoC tunnels that I’ve modified. I removed the mesh baffles at each end, replaced them with plywood panels, and drilled a 50mm diameter hole in the front panel 100mm above the ground (if it’s at ground-level, the hole gets too wet and muddy). A hole is a natural, burrow-like entrance, and the enclosed tunnel is warm, dry, and safe from predators. As they climb up the plywood and through the hole, rats leave physical and chemical traces that lure other rats to the tunnel. 8 out of my last 10 brown rat kills have been in tunnels with hole entrances (and my last weasel).
I hope these tips help.