It is not recommended that you trap and move squirrels. It may be illegal in your state, and since squirrels have teeth and may carry disease, it could be dangerous. But if you MUST trap a squirrel to move it, say, to a point a few blocks away, I suggest using a Havahart trap. Havahart traps can also be used to trap other animals such as mice, or larger critters, depending on the size of the trap.
The best way to trap a squirrel is to use the proper bait and a modicum of patience. Also, you must be diligent if you plan to trap the animal live. therefore, place the trap in an area where you can check it regularly (or see it from a distance) but where it is also a bit out of the way and, above all, out of the sun. A squirrel will die in a short time if trapped in a sunny area.
There are two kinds of traps, one with one door, one with two, and they come in various sizes. Basically, you should browse around for the appropriate Havahart trap
In all cases, the trap consists of a wire cage with a bait holding table on the inside, and one or two trap doors that will drop if the bait table is moved even a little. Once the doors drop, they should remain held in place by a bar that falls down with them.
If the animal you are trapping is too larger for the trap, the door will fall onto the animal and it may escape before it is sealed shut. You may need to switch to the larger trap. If in doubt about the size of your quarry, go for the larger trap … it will be effective in trapping smaller critters, up to a point.
If the squirrel is in your attic or elsewhere in your house, be aware that after you’ve trapped the adult squirrel, you may have babies hiding away somewhere. The best way to get rid of such a squirrel may be, if you can manage it, to disassemble or damage the nest to the extent that the mother squirrel carries the young off on her own. Then clean up whatever is left behind and seal off the nest entrance. That will save a lot of trouble and the moral conundrum you may face when left with a bunch of orphaned squirrel-pups.
Anyway, set the Havahart trap out of the sun but not too close to cover, if possible. Squirrels are more comfortable being in the open, as their main defense strategy is to remain vigilant and run to a tree if anything goes wrong. The base of a tree is an excellent place to put the trap if you can manage it.
Get a bunch of unshelled peanuts from the grocery store. Scatter a dozen peanuts around the trap, put two or thee just outside the entrance way of the trap, and then a handful of unshelled AND shelled peanuts on the trigger plate.
When using the two door trap, put the peanuts near the MIDDLE of the trigger plate so the squirrel is more likely to step on the edge of the plate to get to the peanuts.
Remember to check the trap frequently. If there is a period of time over which you can’t be checking, spring it, but leave the trap in place and keep the peanuts in and around it …. to lull the squirrel into a state of complacency.
If you screw up and let an animal die in the trap, remove the animal and wash the trap with warm water. Don’t use soap. Let it air out. I assume, guess, believe based on experience but no real scientific knowledge (so this may not be true) that traps that have had dead critters in them for a while do not attract as many fresh critters.