Skunks are good at making themselves known. Most people notice skunks by odor. Be aware that just because you smell skunk doesn’t mean a skunk is on your property. Skunk odor can be noticed from far away. Also, animals that have been sprayed could be dragging the odor close to your home.
You also want to determine if the skunks have a den on your property or are visiting. Look for small divots or dug-out areas along fence lines and around the border of your home. This will tell you if skunks are traveling into your yard. Then, look for divots leading under decks and other structures. This will tell you if skunks are living under these structures. Generally, these divots are around hand width. Larger divots or dug-out areas could be from groundhogs. If you find these around structures, use a strong light to inspect for burrows.
Another sign is funnel-shaped damage in lawns. Imagine a skunk digging its nose into the ground for a grub or worm. There could be a few or many. Depending on how much food is for them and how many skunks are feeding.
These are the main signs of a skunk infestation on a property. You may also look for footprints. Another good sign is looking for the white/black hairs stuck to things like porch lattice or fences.