Where Do Squirrels Go In The Winter?

Almost every quick answer to "where do squirrels go in the winter" reaches for the same word: hibernate. It's wrong for tree squirrels, and it's wrong in a way that costs homeowners real money. Squirrels are exactly as active in January as they are in July — the difference is where they choose to be active, and cold weather pushes that choice toward the warmest, driest cavity they can find.

That's the entire correction this page exists to make. Squirrels don't disappear for the season. They relocate their base of operations, and for a growing number of New Hampshire homes, that base is an attic.

In an ideal world, a gray squirrel spends winter in a tree cavity — an old woodpecker hole or a hollow limb — because a cavity beats an exposed leaf nest (a drey) on every measure that matters in the cold: it blocks wind, holds heat, and hides the animal from predators. The problem is supply. A young suburban tree canopy is short on the large, decayed trunks that produce good natural cavities, and that shortage is exactly what turns an attic into the next-best option.

Once a squirrel is inside, it doesn't stop being a squirrel. It caches food nearby, uses spatial memory and smell to relocate its scattered nut hoard through the winter (documented cache-recovery behavior in the peer-reviewed literature), and comes and goes through whatever gap let it in in the first place. And because one of the gray squirrel's two annual breeding seasons falls in January and February, an attic occupant in midwinter is frequently a female setting up a maternity den — which changes both the urgency and the correct timing of removal.

Hibernation is a specific, profound thing: a multi-day-to-multi-week metabolic shutdown. Squirrels never do it. They thermoregulate normally, rely on a thick winter coat and fat reserves, and only den up through individual cold snaps before coming right back out to forage — behavior that looks like brief hibernation from a distance but is nothing like it physiologically.

The one real nuance in this family belongs to flying squirrels, which use brief, shallow bouts of torpor in severe cold (Olson & Bowman) — but even that is a short energy-saving dip, not a multi-month suppression. If your attic noise is nocturnal and quiet rather than loud and diurnal, you likely have flying squirrels rather than grays, and they're also famous for winter communal nesting: groups of 20 or more sharing a single cavity purely for shared body heat.

The cost of believing squirrels "go away" for winter isn't abstract. A homeowner who hears daytime scratching in January and assumes it will resolve itself by spring is giving a female squirrel two to three more months to raise a litter, chew insulation for nesting material, and gnaw wiring — a documented fire and safety hazard, not a cosmetic one (Alabama Cooperative Extension).

The fix is straightforward and genuinely a winter job: inspect, exclude with a one-way door, seal once empty. The only real judgment call is timing it around dependent young if a maternity den is already established — which is exactly the kind of detail a flat "they're hibernating, ignore it" answer erases.