A homeowner in Barrington called us three seasons ago about a wrapped oak that had gone dark on one side. No storm, no ice, nothing loose. The cause was eight inches of cord stripped clean at the trunk, about five feet up, with the tooth marks to prove it.

Squirrels chewing holiday lights is not a rare curiosity in the Chicago suburbs. On heavily treed lots in Hinsdale, Barrington, Inverness and the North Shore it is a routine cause of mid-season outages, and it's almost always misdiagnosed as a product failure.

Why they do it

Squirrels aren't eating the cord. They're wearing their teeth down.

Rodent incisors grow continuously, and squirrels gnaw hard materials year-round to manage that. A cord is roughly the right diameter and hardness for the job — the same reason they chew branches, siding trim, and, memorably for many suburban homeowners, car wiring.

Two things make holiday displays especially attractive:

Cords are new and unfamiliar. A novel object at a familiar height gets investigated. Investigation, for a squirrel, means teeth.

Warmth. Even LED runs are marginally warmer than the surrounding air, which matters in December. Trunk wraps and cords near junctions get more attention on cold nights.

Birds are a much smaller factor — mostly woodpeckers going after siding near a run, or nesting material pulled from a frayed section. Squirrels do the vast majority of the damage.

Where damage actually happens

There's a clear pattern, and it isn't random.

Trunk wraps, three to eight feet up. This is the single most common location. It's the natural travel height on a trunk and where a squirrel pauses.

Junctions and connection points. Anywhere two runs meet creates a bulge — an obvious thing to grab.

Cordage running along fence lines and bed edges. Established travel routes. If a cord crosses one, it gets encountered daily.

Cords resting on the ground under trees. The most vulnerable position in any display, for wildlife and for water both.

Rarely the roofline. Squirrels do run gutters, but a clipped C9 run on a gutter lip presents little to grip. Roofline failures are almost always weather, not wildlife.

Which tells you where prevention actually matters: the landscape layer, not the roof.

What genuinely reduces it

Get cordage off the ground and out of travel routes. The single highest-value measure. Cord routed along a foundation, elevated at junctions, and kept clear of fence tops and low branches simply gets encountered far less.

Use commercial-grade cordage. Thicker jacketing on heavier-gauge outdoor cord is meaningfully harder to strip than thin retail cord. It doesn't make it squirrel-proof; it makes it not worth the effort.

Weatherproof and elevate junctions. A junction wrapped and lifted off the ground is both drier and less grabbable.

Don't leave a chewed section energized. This is the safety point. Exposed conductor in a wet December landscape is a genuine hazard and a GFCI trip waiting to happen. If a run goes dark and you find damage, kill the circuit.

What doesn't reliably work: capsaicin sprays (they wash off in the first rain and need constant reapplication), ultrasonic devices (squirrels habituate), and mothballs (ineffective outdoors and a genuinely bad idea around pets).

If you'd rather not manage any of this, professional christmas light installation routes and elevates all of it as a matter of course — and you can request a free holiday lighting quote to see what that looks like on your property.

Why wooded lots see it most

The correlation is straightforward: more mature trees, more squirrels, more encounters.

Properties in Long Grove, Riverwoods, Inverness and the wooded parts of Barrington run displays with substantially more landscape cordage than a typical subdivision home — a lit drive approach, multiple wrapped specimens, bed lines — and every additional foot of cord in the landscape is additional exposure.

Newer subdivisions with young landscaping see almost none of it, which is why some homeowners find this whole article surprising and others recognize it immediately.

What to do when a section goes dark

Don't assume the bulbs failed. Isolated LED bulb failure is relatively uncommon. A whole section going dark at once points to a break upstream — a chewed cord, a pulled connection, or a tripped circuit.

Check the GFCI first. A chewed cord in a damp landscape will often trip it, which is the protection working.

Then look at the trunk wraps and junctions, three to eight feet up, before anything else.

Call it in rather than splicing it. A field-taped splice in a wet outdoor landscape is a fire and shock risk, not a repair. On a professionally installed display this is a covered call — we replace the damaged run rather than patching it.

Frequently asked questions

Do squirrels really chew Christmas light cords?

Yes, routinely on wooded Chicago suburbs properties. They gnaw to wear down continuously growing incisors, and cords are roughly the right diameter and hardness — trunk wraps three to eight feet up and cable junctions are the most common targets.

How do I stop animals chewing my holiday lights?

Route cordage off the ground and away from fence lines and low branches, elevate and weatherproof junctions, and use heavier commercial-grade outdoor cord rather than thin retail cord. Sprays, ultrasonic devices and mothballs are unreliable outdoors.

Is a chewed holiday light cord dangerous?

Yes. Exposed conductor in a wet winter landscape is a shock and fire risk, and it will often trip a GFCI — which is the protection doing its job. Kill the circuit and have the run replaced rather than taping the damage.

Why did a whole section of my display go dark at once?

Almost always a break upstream rather than bulb failure — a chewed cord, a pulled connection, or a tripped circuit. Isolated LED bulbs failing individually is far less common than a single upstream fault.

Have it routed right in the first place

Most wildlife damage traces back to one avoidable decision: cordage left where an animal encounters it daily.

Twinkle Bros routes and elevates every run as standard across the Chicago suburbs, uses commercial-grade cordage rather than retail, supplies all the product, and covers in-season repairs at no charge through January — so a chewed run is a phone call, not a December project. Everything comes down in January and is stored at our facility.

October dates fill first. Call (708) 316-4569 or request a free holiday lighting quote and keep your display lit through the whole season.