Bird killed in rat trap/tunnel

Sadly, I have killed my first bird (and reported it on TrapNZ). The immature blackbird was killed in a rat trap, placed inside a normal rat tunnel, with peanut butter as bait. The hole in the mesh was 4 squares by 4 squares. Please, does anyone know if there are some standard specifications for wooden tunnels, as I am wondering if we need to make the holes smaller, maybe 3 * 3? I was surprised recently when I heard that some trappers were catching/killing hedgehogs in rat tunnels. That made me wonder if the holes were too large.

I add green food colouring to the peanut butter. I can’t find any papers proving this deters birds but many commercial baits state they are green for this reason. I also add cocoa powder and walnuts (if I have old ones laying about.) Both of those were found to be the most attractive to rats in a recent Lincoln field trial.

We’ve taken close to 70 rats in a couple of bush blocks over the last two months and haven’t struck a bird yet. Our traps are tree mounted Victor Professionals with a custom hood, so not boxed. We did get a hedgehog in the lowest mounted of them.

Our group are using mainly Victor traps in standard length boxes (400mm) and weka boxes (520mm). We also put a 35mm screw up through the bottom of the box at the mid point, which stops the traps sliding too close to the box entrance. We’ve caught 553 pests and 3 sparrows during this time. While it’s sad to trap birds we’re doing our best to keep this to a minimum. Hedgehogs have great PR agents, and aren’t as cute as they’re made out, so they’re on our list as well.

Thanks for the feedback. The screw idea looks very implementable. And with that in mind, maybe I should stop leaving a little taster pile of peanut butter just inside the entrance. Thanks, Paul

Thanks for the feedback Andy. Tree mounted Victors - I had not heard of that, but maybe not so suitable for backyard trapping. Bait adaptation, that is something for me to work on. cheers, paul