where i am trapping the culverts are about 2-3 feet wide and the whole culvert is submerged. there are three right next to each other. where is the best place to put the trap either a colony or a 110. i would like to catch mink or muskrat.

thank you.

Depending on your regs I'd stuff them full of colony traps. I set some huge culverts and set funnel traps just on the bottom and they still went in them when they could of stayed on the surface. They went to the bottom out of habit.

I would forget about using 110s or colony traps and set 3 or 4 floats

Best I can tell you is look for the trail. I generally set square culverts on each side. Not many round culverts that have deep water around here.
just

move up or down 20 ft and catch trhem there.

the water is nearly all frozen over just a few openings by the culverts. and i only have one colony trap.

punt.

I don’t know what your regs are but I’ve made funnel traps the size of the culvert. A rill of hardware cloth will make a bunch of traps. For 2’ culverts I make my funnel trap around 22” in case the culvert is slightly crushed.

This would be a perfect time to use the Bottom Edge set. Put your 110's or 160's on the outside lip of these culverts, against any right angle wall/bank under there. Set a bunch because you will find that even though you may have a half dozen spots that are basically all alike.....one or two will, year after year, out-produce all the others....for reasons known only to the 'rats and mink. A colony trap set in each of the three tubes, if you had three, will prove up the same thing. There is always a sweet spot/path that looks no different than the others, yet it always seems to outdo those other sets at the same stop. Only experience at that stop will show you which one is the best.
Another set that I used during the time things are froze up tight was a sort of baited mink set. I would wire a muskrat carcass to a dead stick long enough to shove the stick into the bottom and still have a bit stick up above the ice. I wanted that stick to freeze in tight. I'd wire a 110 or 160 to the stick so it was JUST BELOW the underside of the ice, while that 'rat carcass was actually hanging out above AND below the ice. Mink running along the edge of the creek would work on gnawing the carcass from above, then go below the ice to do the same. The trap was wired on the back side of the stick, opposite the 'rat meat. Even when there doesn't appear to be any access to get under the ice, those mink would get under there and get caught. If you had any amount of snowfall or rising water, those sets were nearly, but not quite, as much work as pocket sets. BE sets are a "set and forget" deal under the ice. About all you had to do is check for leaves on the trigger now and again.

I told you how to do It.

You would have to have 30 some colony traps to trap those culverts effectively. One Isn't going to cut It.

It would be a pain but if you covered the cage with rocks on the bottom/middle of the culvert to make a tunnel that should draw them in.

thank you all for the advice i think i may build some more colony traps. and i will try the bottom edge sets as well.

Make big funnel traps for the small culverts.
Or ordinary size funnel traps with the diverters on the ends.

thats a good idea thanks boco

Someone put a post on about this so I made one of these and it works well. I welded a 5/16'' fence post rod to a brake rotor. You just move the fence insulator to the height you want the body trap to hang at and put it on the outside corner. I have take 5 rats in this contraption in about a week. Three were on the bottom and two on the top edge. It works with a 160 also.

I use a big piece of wire on the front of my colony traps and slide them into the culvert only on the downstream side so in a flood they do not go into the culvert and plug it. Wire is big enough to block off whole culvert opening. Wire the back door shut to avoid it swinging open in the current. Cover top of wire with grass or weeds to prevent passerbys from seeing it. Eric

I like that idea. Better check it a couple times a night / day

Well If these culverts are 3 footers and are completely submerged your going to have a hard time setting colony traps In them. Then your going to have to stack them since lots of times the rats won't be swimming on the bottom.
The other thing about setting bottom edge sets with either BGs or colony traps Is that the rats aren't always swimming along the edges In these culverts.
Eric gives good advise about setting the down stream ends If you have any current.
The problem with blocking off the culvert Is If you have any debris moving through that culvert that wire Is going to plug up and probably be pushed out of the culvert. And your colony traps will also be plugged up and pushed out along with the wire.

Seems like a lot of work for $3.00 rats LOL

thats a good idea i may have to try that too