The hole should be so that your closed hand can just fit inside it. The kick plates from the Al doors is what I use, it is also, RIPPLED so it holds the FLAT BLACK paint and does not shin up, like the one in the water. When they are trapped inside they swim with their feet and this polishes the metal, were as the ripple does not. There is no rust marks from the Al to consider.
The round ones can be made by incurements of 2 inches each , and then stacked with one end in place. The other end is wired in place at the site. Don't use zip lock plastic fasteners, cause for some reason the teeth find these unred water.

http://www.basspro.com/webapp/wcs/stores...ROSSSELL_SEARCH

Hey jeff I gave some thought to trying something like this at one time , I just have,nt gotten to it yet for some reason I am not sure if it matters but I think the cones are too short. A lot of the traps I have seen the ends / cones are 7-8 inches deep hth

When we did some test work in the 1970's it was found the longer cones were more effective. Seems when they get inside they swim/ scratch more trying to get out and use up the last breath. With the blunt ends they would hit it and swim back and forth and find the holes to get out. The flipper doors are not 100% effective and unless a weight holds the trap to the bottom so they do not roll over, can act as a ladder if the cage is sideways.

Thanks for the help everyone!

Squirrelchaser, Boy, am I ever glad that you showed with all of those years of experience and shared knowledge. I know a lot more about colony funnel traps today than I did two days ago.

Thank you, kind Sir, for the contribution to my continuing education. It is most appreciated!

Jonathan

Thanks for the tips and info in this thread!

A few tricks you can do with colony traps.

1. wrap in black plastic, then dig aritifial run, and cover with mud, plast doesnt let mud fall thru. you can make a fake rat run leading into the buried trap, that works great in some situations. A killer mink set at the right spot.

2. make and 8x12 or 8x16, put in double doors, and wings that you can block a 4' ditch with. double doors keep rats from plugging up outside door so fast. Ive caught 14 rats in one trap i nthe right spot. Kinda like using a 660 for beaver, can block off wider area. shim up w/ T bars to get trap about 2" from surface of needed, dive sticks to get rats into trap.

3. made 8x8, fairly short for hut runs. really just trails thru the reeds. wrap you trap w/ plastic, and attach styrefoam float so top of trap is about 1" underwater. You float trap in wider trails thru the reeds. These are runs per se, but trails that rats usually travel swimming on surface. floats at ends covered with a few reeds become dive sticks, plastic keeps them from sticking nose thru wire and staying alive. Can use in any depth water, usually these swin trails are 2-4' deep in my country.

yep, lot of things you can do with colony traps besides plop down in a run.

In the old days when mink would buy a Texas mikey, funnel traps shone when put around beaver houses, because a lot of times these mink never travel above the ice, but just lived in the houses and swimmed /hunted from them so you never knew they were there.
We did modify some and use them for salmon catches/ counts on the coast one time. There was 2 suprised mammals one time when the trap was lifted. 6 foot me and a 6 foot harbour seal. There was a lot of spashing that went on upon release.

CAD tech from TUNS in Halifax was raised drafting with AutoCad 6 started drafting mechanical plans for my fathers business now I love autodesks inventor and autoCAD 2007 and I play with them some at work for our Municipal unit.

That funnel trap set in the run in the picture - I would add a couple things to that setup.

At each end of the trap I would lay a couple of sticks for dive poles then I would pile grass and cattails up on the sticks to encourage the rat to dive.

They work well in the entry of abandoned beaver huts too.