We found out we had mice so we looked at mouse traps in Homebase. Most were the old spring loaded ones that kill the mice. Others were poison based, and one electrocuted them. Instead we went for a humane trap that just captured them. Unfortunately the mice were smart enough to escape from this. So I built a mouse trap out of Lego.
Fairly simple swing cage. Bars only swing inwards. Mouse goes in and cannot get out in theory. On the first night we caught a mouse, but by morning he had escaped.
I refined the design. I put the swing gate further inside. This time it swung both ways. But the difference this time was that a cog pulled a lever and released a heavy brick door. Sure enough we caught a mouse but he managed to gnaw his way out through the top slats. So we reinforced the top, and this time the trap held him.
I took the mouse trap to the lake near where I work.
I opened the door but the mouse was too scared to come out.
I opened the top to encourage him to escape.
He was still a bit scared, but finally with a bit of prompting he jumped out and sped off.
The only problem with the Lego mouse trap that in an attempt to be kind I had put windows in it. The edge gave the mouse an opportunity to try to gnaw through the Lego. Given a few more hours he might have made it out.
This time there are no edges inside for a mouse to get his teeth on.