Backyard Birding

by Judy Brinkerhoff

A Home of Their Own---Bluebird Boxes for February Nesting
Bluebirds are rapidly losing their nesting habitat due to the cutting down of orchards and other trees...also to the asphalting over of open fields. Their preferred natural nesting sites are in tree cavities and abandoned woodpecker nest holes. They are most attracted to open fields, meadows, and lawns, rather than wooded areas. By setting up nesting boxes we can help replace some of these nest sites.

A nesting box must protect the birds from cold, overheating, rain, and predators, which include snakes, cats, raccoons, and nest takeover by other birds or squirrels.

The box should be at least four feet off the ground, mounted on a metal post to deter climbing predators, and open to a field or meadow, with some trees or shrubs within approximately 25 feet for cover. It should face away from prevailing winds, be away from areas where pesticides are used, and be removed from areas of human activity.

Depending on the birds we want to attract, there are very precise specifications for the construction of the box. For Western Bluebirds, the entrance hole must be 1 1/2" round, and 2" down on center from the roof. This size keeps out starlings, but no smaller, or the bluebirds can't enter. Ventilation holes should be drilled in the top of the sides. The box should be mounted with a slight tilt forward, and the inside of the front panel should be scored or scratched to allow the babies to climb to the entrance hole to emerge.

The box can be constructed of any unpainted solid wood; not plywood or particleboard. Select wood at least 3/4" thick for thermal insulation.

Nesting boxes should be designed so that they can be opened and cleaned out. Most experts say the bluebirds prefer that the box be cleared after each nesting season.

Bluebird nesting boxes can be purchased from Madrone Audubon at the monthly meeting for $11, or by mail for $20, including tax and postage. Write to Madrone Audubon Society, Post Office Box 1911, Santa Rosa, California 95402.

You can also build your own box with plans in the Jan.-Feb. 1999 Audubon Magazine, or from the North American Bluebird Society, on line at <www.cobleskill.edu/nabs/index.htm> or phone me at (707) 887-1500.