Trapping squirrels is very simple. First you must identify the type of squirrel you have, because red squirrels are significantly smaller than grey and black squirrels. Therefore you need a trap with smaller grading for red squirrels than you would for black and grey. With red squirrels in mind, you need half an inch by half an inch grading for your trapping. Although you can use 1 inch by 1 inch traps, red squirrels may actually escape through them with lightning speed when they are scared. This will most likely hurt the red squirrel in the process. Grey and black squirrels can be trapped by using an inch by inch grading live trap or smaller.