Selecting the right nesting box

What makes the nesting box ideal for the birds to use? Ventilation, drainage, protection against predators and ease of maintenance.

Ventilation. Without air vents, nesting boxes can turn into ovens during hot summer days. There are two ways to provide ventilation: gaps between the roof and a side of the box, or ¼-inch holes just below the roof.

Drainage. Water becomes a problem when it sits at the bottom of the cavity. Driving rain comes in the entrance hole, so face the nesting box in any direction other than northwest as most of our storms come from that direction. There should be gaps at the corner of the floor or holes drilled in the floor for drainage.

Entrance hole. Look at the entrance hole on the front panel of the nesting box. The size of the hole helps determine which bird will seek out the house. A 1-inch hole will welcome House Wrens; 1⅛ inch is ideal for chickadees. Titmice and nuthatches like the same size house but with an opening of 1½ inches. Bluebirds prefer the same size opening but a larger house. 

Predators. Predator guards can make a big difference between a safe brood and one a raccoon or squirrel can reach. The guards fit in front of the opening. Some are metal, which prevents predators from enlarging the hole to reach the hatchlings inside. Other guards are made of wood or plastic and protrude from the house.  

Access. You want a nesting box that can easily be cleaned out after each brood or at the end of the summer. If birds check out the house in spring but don't move it, look inside for English Sparrows, snakes or insects. Check for fleas, flies, lice or their larvae in the house, too.

You can stain a house made of natural wood or put a preservative on it. Only apply to the outside of the house not the inside nor inside the opening. Birds do not care what the house looks like as long as it meets the opening and inside size preferences; so if you want to paint it - go for it!