Step 1: How It Works
Step 2: Materials
1 sturdy box. My city-issued recycle bin was perfect for the job.
Plywood or chipboard (OSB) for the base.
Some scraps of wood for the box hinge (2x4), side rails (1x2), and prop (1x2)
Screws to assemble (for example #8x1" and #8x2" wood screws)
2 hinges, and screws for mounting (for example #8x1/2" wood screws)
1 screw hook
1 clamp-type paper clip
1 small keyring
And, a saw and a screwdriver.
Of course you can improvise with whatever materials you have on hand.
Step 3: The Base
I made my base from 2 pieces of chipboard that were lying around in my basement. I had to screw them together with additional pieces of chipboard, but that worked out well because the extra chipboard pieces also functioned as side rails to hold the box in place when the box is down. If you have a single piece of plywood or chipboard, you may need to screw on side rails, spaced far enough apart that the box will fit loosely between them. Pieces of 1x2 would work nicely.
For the box 'hinge', cut two pieces of 2x4, one short enough to fit inside the box, the other about as long as the width of the box. Screw them to the base as shown, and make sure that the box fits loosely between them and is able to tilt upward at least 30 degrees. If you don't have a recycle bin, you can make a box from plywood, then you would just use regular hinges to attach the box to the base. I didn't use regular hinges for my trap because, really, the recycle bin belongs to the city, and I didn't want to damage it. in any way.
For the prop, cut two small pieces of wood (1x2 would work well), one about 4 inches long, one about 2 inches long. Attach them together with a hinge as shown. Use the second hinge to attach the prop to the base. The hinge I used for this is a cabinet hinge which wraps around and screws to the back of the cabinet door, if you are using a regular hinge it will be screwed to the other side of the prop. Make sure that the prop is positioned so that when it is supporting the box, it is vertical, and when the prop is down (as in the first picture) it is not in the way of the box.
Step 4: The Prop Hardware
The screw you see is used for adjusting the prop. It prevents the prop hinge from going fully straight, so that the prop is just about ready to fall when the trap is set. You can adjust the screw in or out to adjust the prop, making it easy to trip but not so easy that it is tripped by the wind.
You can see that I made the prop from a piece of cheap compressed cardboard stuff which split when I screwed in the hardware. But it still works. Use real wood instead.
Step 5: The Bait
My bin already had holes in the bottom corners, I passed the string through one hole and tied a washer to the end. In the middle (actually, closer to the prop end), I tied a clamp-type paper clip to hold a piece of bait. On the other end I attached a small key ring, this allows easy setting of the trap. You will need to set up the trap and adjust the length of the string so that it is almost straight when the trap is set. An easy way to make the string just a little bit shorter is to tie a knot in the string.
For bait I used a rabbit treat called "Yogurt Yummies" that I got at a pet store. It was very effective. You can try other things rabbits like, carrots, lettuce, apples, etc., but remember it has to be better than what they are already eating in your garden. Put a piece of bait in the clip, and put some more on the base inside the box to get their attention.
To set the trap, put the box in position, reach inside the box and slip the keyring onto the screw hook, then set the prop to hold up the box.
Step 6: Hasenpfeffer!
Surprisingly, after lifting the box the rabbits sat motionless long enough to be photographed before running off into the woods.
July 23, 2010 - finally caught rabbit #3 (4th photo). In this photo you can see that I taped some bricks to the sides of the box to make it heavier. One day I found the trap down but slightly out from between the side rails, and empty, I thought that an adult rabbit might have got caught and was strong enough to escape, so I decided to make the box heavier.
August 16, 2010 - caught a mouse! It was great to find out that the release mechanism is sensitive enough to do that. I had removed the bricks by this time (actually the tape gave out and they fell off).