Backyard Birds

Bird Houses & Nesting Box Woodworking Plan for Boreal Owls

The below Nestbox is designed for Boreal Owls. squirrels may use this box.

Suitable Nestbox Size: ~ 9 – 10 ” inches high x 7 wide x 7″ deep. Mount about 4 to 6 feet high on a metal pole. No perches at the entrance holes as they would aid predators.

Floor Dimensions: At least 7″ x 7″.

Material to be used: Red Cedar (more durable than other wood material), rough cut boards or exterior-grade plywood at least 1/2″ thick. Unpainted. Ventilation openings in the floor and under the roof. Although some experts disagree with the notion that ventilation openings are needed at all. Please refer to this article for further information. This may also depend on location of nest box, exposure to direct sun as well as material used to build the nest box.

Entrance Hole: About 2.5″ h x 4.5 ” w x, about 14 – 15 inches above the floor.

Roof: Hinged, secured with shutter hooks. Sloped down, overlapping on the sides and the front reduces exposure to rain and makes it more difficult for predators to get to the chicks or eggs.

Hardware: Best to use corrosion resistant, stainless steel and dichromate plated screws

Predator Guard: An inverted metal cone attached below the nextbox will provide some protection against predators.


Mount either on a pole or in a tree at a height of at least 10 feet.

Close to forest edge or clearings.

The entrance hole in particular should be protected from the elements as much as possible.

Position nest far enough from roads, paths or trails to minimize disturbance.

Take nest box down after each breeding season, and repair and sanitize before reusing.


Gordon Ramel

Gordon is an ecologist with two degrees from Exeter University. He's also a teacher, a poet and the owner of 1,152 books. Oh - and he wrote this website.

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