Elevating DOC200 boxes in a swamp forest

Looking for communtiy input and advice on how to keep DOC200s dry in a location that regularly floods.

Issue: I trap in a kahikatea swamp forest that floods about once a year on average (or five times this last year :angry:) Typically this pushes traps around, fills them with silt and mud, and makes any catches rot really quickly. Occasionally the floods are powerful enough to carry a trap away.

I’m interested in ways of mounting or setting the traps up above the typical water level (maybe 50 cm) so I don’t have these issues. Ideally the sets would still be equally attractive to the predators that I’m trapping. Anyone else deal with this sort of issue?

Something like a mink raft?


Or Waiheke’s floating bait station.

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What are you trapping? Maybe a tree mounted trap would be better? Like if it’s just rats, then Victors in wooden tunnels on trees, jut out of the water line?

Or if you have the funds, AT220s?

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Kia ora @cooperii , we trap in and around a large wetland in coastal otago. We have very few big trees like you but definitely the same trickiness of wildly fluctuating water levels in some areas!

For our BT200s we have mounted them on posts (we have used a quarter round superpost from Goldpine, about $9 each for 1.8m), screwed through the base into the top of the post with decent length screws, and attached a ramp to the door out of timber or ply offcuts.

We have definitely still had catches in our post traps, in terms of choosing location we have gone with in or beside bushy bits so the animals don’t feel so out in the open. In a more foresty situation I’d go with looking for natural runs and pathways and placing it on them, plus scuffing up that line or even assisting the flow of that by using sticks or leaf litter on the ground a a kind of ‘funnel’ to direct passers by into interacting with the ramp. Things like ponga ferns or dead branches leant against the trap can make it blend in a bit better as well.

It sounds like your traps wouldn’t need to be as high as some of ours so less change from a grounded trap!

We also use A24s on floating platforms with a waratah in the middle that they can slide up and down in high water - a piece of carpet at each end forms the ramp. We use those in more remote areas that we can’t get to as easily or often, where there isn’t very firm ground, and where the water level fluctuates a lot.

I’ll see if I can find some photos on my work phone and pop them up for you, feel free to send me a message if you have any specific questions though.

PS where is your kahikatea grove? we have just one ~4 hectare remnant stand of kahikatea left on the Taiari plains (which would have been all kahikatea amongst other species), and it is quite dry there, although it does have a wee waterway running through the middle. We’ve just last week put a couple of AT220s out as the start of our protection plan for it

We’ve got both ship rats and Norway rats on site. The Norways are always caught on the low ground near waterways. We are just getting to the point of adding Victor rat traps in wooden boxes, which will be mounted in the trees out of the flood zone. Those Victors are mostly intended to target mice and ship rats. But ideally I’d like to keep the DOC200s active and available on the ground for the Norways (NAWAC testing has confirmed that big Norway rats can survive a Victor trap and I don’t want them getting trap shy).

DOC have used floating platforms with trap tunnels attached on top in wetland areas that regularly flood in Fiordland like this for a while -

A couple of sheets of ply with some flotation sandwiched between such as foam pool noodles or closed-cell foam blocks. The platform can be tethered to a tree with rope or chain so it doesn’t float away, just rises & falls with the water level and doesn’t get full of silt.


Found a couple of images, the one on the post isn’t a great location example but you get the idea of the premise. The lower one is attached to the side of a boardwalk


How have these raised traps worked? Did you catch the amount of pests you expected to?

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They seem to have worked well - it did take a bit longer than our ground traps for the first catches to be made, but all the lines where we have raised traps are making catches. It’s a little hard to compare catches between lines as each line has it’s own nuances that influence the numbers we catch in those areas anyway!

The areas we have them don’t really have another option, so given that otherwise we would have no traps, they’re working great!


Oh thanks for the update, really good to hear they’re working well.