rksoon,
A bottle trap can be made with a bottle, can, or length of PVC tubing, anything a critter that falls into it can't get out. The "Bottle is inserted vertically into a hole, and the dirt packed around it, the open top flush with the ground surface. a flat bottomed rock, board, or piece of debris is supported so there is a slit opening, so the critter, seeking a place to hide, falls into it.
it is good for scorpions, mice, some bugs, snakes, sometimes chipmunks. You can bait it, or position it so you can "beat" the area and chase critters into it. It works for scorpions without the cover, just bury it right next to the entrance.
Be careful, especially if you use an opaque container. You can use a hiking staff or suitable stick to kill whatever fell into it, or slide a screw lid onto the jar until you can figure what is in there.