I have a beautiful new bird house (nest box) to put in our yard this spring. Since I live in northern California I probably should have put up the bird house by now.

Bird houses can be put up one month prior to the arrival of nesting birds. Houses should be up by February in the warmer climates and by late March or early April in colder climates.

Before I put up the new bird house I plan to modify it to protect the bird house and the birds who build a nest from gnawers and predators. We have three bird houses (nest boxes) in our backyard from previous years. The opening of all three houses has been gnawed so that the houses are no longer safe for our backyard birds and birds will probably not nest in them.

Birds choose to nest in a bird house because they feel safe from predators. I’ve found some suggestions to protect my bird house from predators.


  • Make sure that the entrance opening is the correct size for the birds you are trying to attract.
  • Never use a perch on your bird houses. Perches only invite predators. If you buy a bird house with a perch, remove it.

I’m hoping to attract and make a home for one of these species.
The recommended diameter size of the bird house opening is given for each species.

Bewick’s Wren – 1  1/4 inches
Chestnut-backed Chickadee – 1  1/8 inches
Oak Titmouse – 1  1/4 inches
White-breasted Nuthatch – 1  1/4 – 1  3/8 inches

The bird house I ordered from a well-known online bird store has an opening diameter of 1 1/2 inches and while it appears a bit large, the company says it will attract all the species I have listed.

Cats and raccoons will attack the bird house from above. They will either climb the tree that the bird house is mounted on or they will jump from a nearby tree. They will then reach into the nest box and destroy the nest.


  • Mount your bird house on a pole or a tree at least 10 feet from the ground and at least 10 feet away from any structure that a cat or raccoon could jump from.
  • Using a metal baffle will keep many bird house predators from climbing up to the bird house. A piece of metal air duct is inexpensive and a perfect solution for this.
  • A roof that over hangs the front of the bird house at least six inches will prevent cats and raccoons from reaching inside from above.
  • Attach a block of wood ¾” to 1″ around the entrance hole. This will make it more difficult for cats and raccoons to reach inside.

Squirrels will destroy the bird house by chewing at the entrance hole to get inside. This makes is easier for the squirrels and other predators to get inside and destroy the nest and inhabitants.


  • Attach a block of wood ¾” to 1″ around the entrance hole. This will make it more difficult for the squirrels to enlarge the hole.
  • Place a piece of sheet metal around the entrance hole, matched it to the size of the hole. This will protect the entrance hole from being enlarged by squirrels and other birds.

I also found that squirrels can be deterred from chewing or gnawing at the opening by applying a hot pepper solution to the wood around the opening. Squirrels and other mammals taste the hot pepper, while birds do not. The hot pepper is not harmful to birds.

To make a pepper-based squirrel repellent, mix a bottle of very hot sauce with a gallon of water and a teaspoon of mild dishwashing liquid. Mix thoroughly and apply to opening or spray on anything you don’t want the squirrels chewing on.

Another repellent is made from 1 cup crushed chili peppers and dried cayenne peppers mixed with a gallon of water. Allow the pepper-water mixture to steep for a few days. Then strain with several layers of  cheesecloth  and apply to opening. Repellent may need to be reapplied occasionally.

I plan to apply a hot pepper solution to the area around the opening and then attach a block of wood or a piece of metal to protect the opening and the birds inside.

I’ll let you know if I am successful!