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Why Do Squirrels Break Branches? Nest Building and Teeth

Squirrels snap green twigs for drey material, to reach buds and sap, and to wear their incisors down. How to tell nest cutting from bark stripping.

By Zakaria 4 min read Save to Pinterest — opens Pinterest in a new tab
A red squirrel at the base of a tree carrying a cut twig in its mouth
Photo: krzysztofniewolny, Pixabay Content License, via Pixabay
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The twigs on your lawn are building material. A squirrel drey is woven from fresh green twigs, and green wood only comes off the tree one way — bitten.

Reason 1: the drey

A squirrel’s nest is a ball of leafy twigs, roughly the size of a football, wedged in a fork or against a trunk. It is built from the outside in:

  • An outer shell of cut green twigs with the leaves attached
  • An inner lining of shredded bark, moss, grass and fur
  • A single small entrance, usually facing the trunk

Green wood is essential. It bends into the woven shell and then dries in place, locking the structure together. Dry twigs collected off the ground snap instead of bending, which is why a building squirrel cuts fresh rather than gathering.

A single drey takes dozens of cuts over a few days, and squirrels maintain more than one at a time and rebuild before each litter. Not every cut twig is used — a squirrel that mis-judges a bite drops it, which is where the lawn litter comes from.

Reason 2: what is at the end of the twig

  • Buds and flowers in spring, which are the most nutritious thing on the tree before leaves harden
  • Sap, reached by biting through to the phloem at a thin point
  • Developing fruit, cones and nuts, taken green well before they ripen

The twig is in the way, so the twig comes off.

Reason 3: teeth

Squirrel incisors grow continuously throughout life — in the region of six inches a year — and must be worn down against something hard or they overgrow. Twigs, bark, nut shells and, unhelpfully, cables and timber all serve. A squirrel with nothing to gnaw develops malocclusion and starves.

Telling the damage apart

signsquirrelstorm
Cut endclean, angled, tooth marks visibletorn, split along the grain
Twig sizeconsistently pencil-thick or lessmixed, some large
Leavesgreen and freshvariable
Timingaccumulates over days, in dry weatherall at once
Location on treescattered through the canopyoften one side, or a failure point

Bark stripping is the one that matters

Snapped twigs are cosmetic. A strip of bark running all the way round a branch or trunk is a girdle, and everything above it dies. On a young tree a few girdles can kill it. If you are seeing bare patches of pale wood rather than twigs on the ground, that is a different problem.

Why bark stripping happens

  • Late spring and early summer, when cached nuts are gone and sap is rising
  • The sugary phloem just under the bark is the target
  • Nest lining — shredded bark is the soft inner layer of a drey
  • Smooth-barked species suffer most: beech, sycamore, maple, young oak
  • High local density makes it worse, which is partly a feeder problem

What you can do

Not much on a mature tree, and usually nothing is needed. For a young or specimen tree:

  • A smooth metal band around the trunk, about 2 ft wide with its lower edge at least 6 ft up — only works if no neighbouring branch or fence gives lateral access, and squirrels jump several feet
  • Prune away bridges from adjacent trees, roofs and fences
  • Remove or relocate bird feeders to reduce how many squirrels the garden supports
  • Protect the specific thing — netting over fruit, mesh collars on young trunks

What does not work: trunk sprays, ultrasonic repellers, mothballs, greasing the trunk — slippery coatings also ruin the bark and trap birds and insects.

The thing worth keeping in mind

A squirrel cutting twigs in February is making somewhere to raise a litter in March, and the lawn litter is the by-product of that rather than an attack on the tree. On an established tree it is not damage worth managing. On a four-year-old maple being stripped in June, it is.

Common questions

Why do squirrels break branches off trees?

Mostly to build with. A squirrel drey is made of leafy green twigs cut fresh from the tree, because green wood bends into a sphere and dry wood snaps, so a nest-building squirrel cuts dozens of small branches in a few days. The other reasons are reaching buds, flowers or sap at the twig tip, and wearing down incisors that grow continuously. Some of the cut twigs are dropped rather than used, which is why you find them on the ground.

Is squirrel branch damage bad for the tree?

Twig cutting is cosmetic on an established tree — a mature oak or maple loses a trivial fraction of its canopy. Bark stripping is the version that matters, because a strip all the way round a branch or trunk girdles it and everything above that point dies. Repeated stripping on a young tree can kill it outright, so the distinction between snapped twigs on the lawn and bare patches of wood on the trunk is the one to make.

Why do squirrels strip bark from branches?

For the sugary phloem underneath, usually in late spring and early summer when sap is rising and cached nuts are gone, and for nest lining — shredded bark is soft bedding material. Grey squirrels in particular do this, and it is worst on smooth-barked species such as beech, sycamore, maple and young oak. High population density and a poor nut year make it more frequent.

What time of year do squirrels cut the most twigs?

Two peaks, matching the two nesting seasons: late winter into early spring, and midsummer. Dreys are built or rebuilt before each litter, and squirrels maintain more than one at a time, so a single animal may be cutting material repeatedly across the year. Autumn twig fall is more often wind or a fungal problem than squirrels.

How do I tell squirrel damage from storm damage?

Look at the cut end. A squirrel leaves a clean angled bite with visible tooth marks, often with the leaves still green and fresh. Storm damage tears, splits along the grain and leaves a ragged stub. Squirrel-cut twigs are also consistently small — pencil-thick or less — and arrive on a dry day, while storm litter is mixed in size and arrives all at once.

Can I stop squirrels damaging my tree?

Not easily on a mature tree, and usually it is not worth trying. For a young or specimen tree you can fit a smooth metal band around the trunk, two feet wide and at least six feet up, to stop climbing, provided no neighbouring branch gives access — squirrels jump a long way laterally. Removing feeders nearby reduces local density. Trunk sprays and ultrasonic devices do not work.

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