When the “Wrong” Tenant Moves In: Squirrels in Bird Houses Explained
A flying squirrel in your bluebird house? Yup. It happens.
I saw this issue pop up recently in my neighborhood forum, and because I’m a trained squirrel rehabilitator with the Wildlife Rehabilitation Group of South Carolina, I figured it was worth sharing a little real-world guidance.
Late winter into early spring is the prime nesting season. That means birds are scouting boxes… and squirrels are, too. And when you lift the lid and see a pile of leaves instead of neat little pine needles, it can feel like someone crashed the wrong party.
Let’s walk through what’s actually going on.
First Things First: Squirrels Don’t Just Have One Nest
Even if there are no babies in the bird house itself, that squirrel may absolutely have babies nearby.
Squirrels — including flying squirrels — commonly maintain multiple nests. Think of them as “primary residence” and a couple of Airbnbs. If disturbed, a mama will move her babies between sites.
Which means this: If you trap or remove mom, you may be leaving babies behind in another nest you never saw. And without her? They have no chance of survival.
It’s one of the hardest parts of wildlife rehab — the unintended consequences.
About the Babies (Why They’re Easy to Miss)
Here’s what most people don’t realize: Baby squirrels, especially flying squirrel babies, are tiny. Jellybean-sized. Pink. Hairless. Often buried deep in the softest, lowest part of the nesting material.
They are shockingly easy to miss if you’re not trained to look for them.
So if you feel compelled to check a box yourself, slow down.
If You Check a Nest, Please Do This:
• Wear gloves. Not because squirrels are aggressive — but to protect them from us. *
• Confirm mom isn’t inside first. Watch the box until you see her leave, or use a small endoscope camera to peek inside.
• Wait a bit after she leaves. A stressed mom may return quickly. If she feels unsafe, she can bite in defense — or worse, abandon the nest.
Sift slowly and methodically. You’re looking for small pink babies tucked deep in the nest bowl.
Important: Relocating Squirrels Isn’t Legal (or Kind)
Most people don’t realize that in South Carolina (where I live), and many other states, relocating wildlife without proper authorization isn’t permitted.
The goal of that law? Prevent the spread of disease, ecological disruption, and unnecessary suffering.
Trapping a squirrel and releasing her “in the woods” may feel compassionate. But relocated squirrels often:
• Fail to find food in unfamiliar territory
• Get attacked by resident squirrels
• Die from stress
• Leave behind dependent babies
It’s rarely the happy ending people imagine.
The Humane Solution: Timed Exclusion
If your goal is to protect birds while also keeping squirrels safe, here’s the path forward.
1. Confirm whether babies are present.
If babies are in the box, wait. They typically wean and leave on their own in 4–6 weeks. That’s it. A short window in the grand scheme of things.
2. If you are absolutely sure the box is empty, begin temporary exclusion.
Block access to encourage mom to settle into one of her other nest sites. Because squirrels are site-faithful, if the opening stays accessible, she’ll return — and possibly generation after generation.
3. Keep the box closed for 3–4 weeks.
This gives her time to fully establish elsewhere.
4. Make the box squirrel-resistant before reopening.
If you skip this step, you’ll be back here next spring.
To support birds:
• Install a metal hole guard so squirrels can’t gnaw the birdhouse opening larger.
• Mount boxes on smooth metal poles with predator baffles.
• Avoid mounting on trees or rough wooden posts.
• Place boxes far enough from trees that squirrels can’t easily jump or glide onto them.
Exclusion works. Trapping doesn’t.
A Quick Perspective Shift (From a Squirrel Lover)
I know. Squirrels can be frustrating if you love birds. (Trust me — my husband is a die-hard bird guy.) But squirrels aren’t villains. They disperse seeds. They support forest regeneration. They feed hawks, owls, foxes, and native predators. They’re ecosystem participants, not party crashers.
And honestly? Baby squirrels peeking out of a nest box are pretty magical.
If you’re open to it, one simple option is this: let mama squirrel raise her litter in the box this season — and put up a second birdhouse designed with proper exclusion features.
With a little planning, you can support both. Nature doesn’t have to be either/or.
One Last Thing
If you ever find an injured squirrel or truly orphaned babies, or if you need help safely checking a nest, please reach out to a licensed rehabilitator in your area.
*For the record: squirrels very rarely carry rabies. They typically do not survive a rabid animal bite long enough to transmit it. The bigger risk here isn’t rabies — it’s human error.
