How to Tell if Pest Damage Happened During Winter

 

Pest damage that happens during winter has signs that set it apart from damage done in other seasons. The key is to look for clues about the time of year the damage happened and the type of pests that are most active in cold vs. warm months. By carefully examining the damage, checking the condition of plants or stored items, and considering the biology of common winter pests, you can often tell if the harm was caused during the winter.

 

Why Does Timing Matter?

 

Knowing if pest damage occurred over winter is important for several reasons. Many pests behave differently based on the season. Some are dormant in winter, while others, like rodents and certain insects, seek shelter inside buildings or beneath bark and soil to escape the cold. If you know when the damage happened, you can better plan pest control and prevent similar damage in the future.

 

Main Signs of Winter Pest Damage

 

• Type of Damage:  In winter, you’re more likely to see damage from pests that stay active during cold months—like mice, voles, squirrels, rabbits, and insects such as carpenter ants. Winter damage commonly includes:
  • Bark gnawing or stripping on trees and shrubs (especially at the base or just above the snow line).
  • Chewed or clipped stems and twigs on young plants and trees.
  • Girdling—when bark is eaten all the way around the trunk or branch, cutting off flow of water/nutrients.
  • Rodent burrows or runways beneath snow or mulch.
  • Stored products (in homes or garages) with gnaw marks, droppings, or shredded nesting materials.
• Freshness and Condition of Damage:  Winter damage tends to look newer in early spring. If you notice fresh, pale wood or still-green plant tissue at the site of chewed bark or branches as snow melts, it likely happened during winter months when everything else was frozen and growth was dormant.
• Location of Damage:  True winter damage usually appears at or slightly above the snow line, because snow acts as a shield and an access point. Rodents, rabbits, and voles often use the snow as cover for feeding, and damage stops abruptly where the snow depth reaches its highest point on trees or shrubs. This is called a "snow line effect."
• Pest Activity Signs:  Look for tunnels, nests, runways, and droppings under mulch, near the foundation, in garages, or beneath shrubs—especially where snow or ice once covered the ground. Mice and voles leave narrow, smooth-worn paths in grass beneath melting snow, and often you’ll see piles of droppings concentrated in those spots.
• Plant Recovery:  If a tree or shrub shows no sign of healing or regrowth along chewed or girdled areas, and buds near damage are dry or dead in early spring, this suggests the harm was done while the plant was dormant in winter, and no repair was possible at that time.

 

Common Winter Pests and Their Damage

 

• Voles:  Small rodents active under snow that eat bark and roots. They leave trails and little "runways" in the grass, plus gnawed bark at lower trunks.
• Mice:  Often invade sheds, garages, and homes for warmth, resulting in chewed packaging, insulation, or wires and shredded materials for nests.
• Rabbits:  Chew off branches cleanly at a 45-degree angle, often just above snow level. They may also girdle tree trunks.
• Deer:  Tear off branches and buds higher off the ground if snow is deep enough to allow them to reach up further than usual.
• Insects (less common in winter):  Some insects like carpenter ants and overwintering beetles can chew wood or plant material inside protected spaces, but outside insect activity is rare in true winter cold.

 

How to Confirm the Timing

 

• Check the appearance and freshness of damage compared to new growth (bark stripped during winter looks fresh in early spring, but weathers and darkens quickly after exposure).
• Look for the snow line pattern: damage that matches the old snow height.
• Look for signs of current pest activity—old droppings, runways, nests, or gnaw marks that aren’t active now but were fresh when snow first melted.
• Assess weather history—if you had heavy snow cover or long cold spells, and you see damage that fits the descriptions above, it’s very likely winter-damage.

 

What to Do Next

 

If you suspect winter pest damage:

• Clean up and repair as best you can (pruning, wrapping, or supporting injured plants).
• Set up barriers or wraps around tree bases next fall to prevent repeat damage.
• Seal building gaps or cracks to discourage rodents.
• Monitor areas for new pest signs as spring and summer arrive.

You never need to guess—you can always check these signs each spring, and when in doubt, a pest control or horticultural expert can confirm the timing and type of damage.