Why this happens
Porcupine problems rarely announce themselves as wildlife problems. They start as something inexplicable.
The plywood on the shed has been chewed away along one edge. The handle of a good axe left leaning in the barn is ruined. A section of deck rail looks like it was worked over with a rasp. Someone finds the brake lines on a truck chewed through, or the seat of a boat destroyed, or a saddle wrecked. None of it makes sense as animal behavior, because none of it is food.
Then you notice what the damaged things have in common: salt. Sweat-soaked wood, sodium-containing glues, road salt on a vehicle underside, salt-cured leather. Once you see the pattern the whole thing resolves at once.
Porcupines need sodium and their winter diet supplies almost none, so they hunt for it — and they are remarkably good at finding it. They are large, slow, nocturnal rodents, excellent climbers, and completely unhurried. They cannot chase anything and have no interest in you.
Winter is when this peaks, and everything converges: the diet shifts to bark and needles so tree girdling starts, the sodium deficit becomes acute so the structural chewing starts, deep snow keeps them close to the den so damage concentrates in one area, and road salt is everywhere.
They den in the void under sheds, barns, porches and outbuildings — dry, sheltered, safe from fishers — and they come back to the same den year after year.
What to do now
Deal with a quilled dog first. If that has happened, it is a same-day veterinary visit and it outranks everything else on this page. Do not attempt removal at home.
Follow the salt. Look at what has been chewed and you will usually be able to predict what gets hit next. Move it.
Find the den. Under the shed, barn, deck or porch, marked by a mound of pellet scat at the entrance and shed quills nearby. In snow, follow the worn trails.
Check your trees. Bark stripped in patches high on the trunk and out on branches, with coarse tooth grooves and nipped twigs on the ground below. If a trunk is stripped all the way round, that tree is finished.
Check vehicle brake lines and hoses if anything has been parked outside. This one is a genuine safety issue, not an inconvenience.
Keep dogs leashed at dusk on rural property in winter. That is when most quillings happen, and dogs that have been quilled once frequently do it again.
When to call
Call when you find chewing you cannot explain on plywood, tool handles, deck rails or vehicle components.
Call when you find a den with a scat mound under a shed, barn or deck — that is a resident animal, not a passing one.
Call when trees are being stripped high on the trunk, especially if you have conifers you care about, because girdling is not reversible.
Call before winter if you had a porcupine last year. Autumn is the right window to close dens and protect trees, before the animal is established for the cold season.
Brian handles porcupine work across the rural corridor — Clintonville, Marion, Tigerton, Embarrass, Big Falls, Iola, Manawa, Waupaca and the wooded farmsteads and cabins between them, where woodlots, outbuildings and stored equipment make this a routine part of winter wildlife work.
Full profile at porcupines. Other animals that den under the same structures — worth closing the void against all of them at once — are skunks, groundhogs, foxes and opossums.