A port protector is an easy-to-install piece that goes over the hole of your birdhouse. It is usually made of a metal like copper, though beautiful slate protectors (pictured below) are also available.
Here's why you should buy birdhouses with port protectors or add them to your existing birdhouses.
1. Protect the hole from being enlarged by squirrels.
Squirrels can chew the hole opening of most birdhouses, making the hole bigger than it needs to be for the birds. When the hole is enlarged, it makes it easier for squirrels and other predators to enter the box and cause harm to the eggs, nestlings, and/or parent.
2. Protect the hole from being enlarged by woodpeckers.
Woodpeckers may enlarge the hole to use the box themselves (which is not necessarily a bad thing), but again, if it makes the hole larger, it also makes the inside more accessible to predators.
3. It makes the box look nicer.
Chewed up edges never look nice while a nice copper or slate port protector can add a decorative touch to even a plain wooden nestbox.
4. A port protector can repair a damaged hole.
If the nest hole has been previously widened, you MAY be able to cover up the damage with a port protector and restore the nest hole to its proper size.
5. It's a small investment for lots of benefits.
Basic porthole protector: less than 5 bucks.
Benefits to the birds: priceless