CHARLESTON, W.Va. -- I know it seems like this winter will never end, but days are getting longer, and just a few days ago, I finally saw blue sky and felt the warmth of sunshine.
With longer days and bright sunshine comes hope in the form of bird song. And no voices sound better on a cold February day than those of eastern bluebirds, Carolina chickadees, tufted titmice, and Carolina wrens.
It will be at least another month before these birds start building nests and another few weeks until they lay eggs, so there's still time to build a few nest boxes for these cavity-nesting backyard birds. Few backyard projects are more rewarding.
The supply of dead trees and natural cavities limits the number of cavity-nesters that inhabit any area. Providing nest boxes is a simple solution to this nest site shortage. But only cavity-nesters, not open nesters such as robins and cardinals, use nest boxes or birdhouses. Only cavity-nesters have the strong feet and fearless curiosity required to explore deep, dark nooks and crannies.
The birds that use nest boxes vary with habitat. Eastern bluebirds prefer open country with a few scattered trees. Hay fields, pastures, cemeteries, and golf courses are ideal bluebird habitat, and if there's a pond or wetland nearby, tree swallows may also use nest boxes in these areas.
If you live in a wooded area, don't expect bluebirds. Chickadees, titmice, wrens, and maybe even white-breasted nuthatches use nest boxes in more wooded settings.
A simple four-inch by four-inch by 10-inch box with an inch-and-a-half hole is all bluebirds and these other small cavity-nesters require. Build a bigger box (8" x 8" x 18" high with a three inch hole), and you might get an eastern screech-owl or American kestrel.
Any untreated lumber will do, but exterior plywood is relatively inexpensive and ages well. Use stock that's three-quarters to one inch thick. It insulates nests from spring chills and summer heat.
The actual design and appearance of the box are unimportant to cavity-nesting birds. They simply require a secure site that protects the nest from foul weather and predators. Here are a few basic tips to keep in mind: