I run a project in urban Auckland and use rat and possum traps. I had discounted using stoat traps as I was under the impression they weren’t common around urban/suburban areas. I assume the habitat could likely support them? the reason I bring it up is one of our members thought they saw a stoat and had the exact same thought as me until they saw it. Even then would the extra $150 dollars be worth it when they may may be in numbers too low to catch/control enough to make any kind of substantial difference? I’m curious to here opinions and experiences. -cheers Dan
Hi dan, perhaps your project could buy a few tracking tunnels and/or chew cards - check out the Predator Free NZ website for more about these.
This would be the way to know if you have a stoat problem or not before you make the bigger investment in DOC200s. Stoats are in much lower densities than rats, though, so you will need to have maybe 30 - 100 cards out for whatever amount of time PFNZ says (keep a list of where they all are, or set up a monitoring line in TrapNZ? 
)
Various sellers sell chew cards in varying quantities or you can make your own if you can get hold of corflute, the stuff Real Estate signs are made of.
Tracking tunnels are a little more expensive but perhaps easier to interpret the results.
I have experience with the above but I fear they would be around in numbers far too low to detect or catch, so the question I’m sort of wondering is if anyone knows if they are actually around in numbers too low to detect but high enough to merit a stoat trap. I guess the benefit of a doc200 is it also works on rats so it wouldn’t be a total loss if no stoats were caught but still the price tag definitely makes me question if its necessary. I do have access monitering tools like cameras but I fear them and any Doc-200s may be a risk of being stolen or wasted.
Yeah, you probably want to budget as much for security (s/s boxes, s/s “zip ties” and/or chains, security screws and bolts, etc.) as for the trap itself. Yay.
Humans are sad beggars. The project I’m on has a couple of traplines along roads, and a couple more on public tracks, and DOC200s and 250s seem to disappear at a steady rate despite being pegged down. Goodness knows what the thieves do with them.
If you can keep them, DOC200s should last basically forever since they are stainless steel. An heirloom! 
The cost might not be so bad if they last you 50 years.
Edit: our project is rural, and we get about 1 stoat for 20 rats. I’d expect it to be more like 1 to 100 in urban areas because there is so much more food for rats. I don’t know if that helps.
Edit 2: more like 1:15.