Packed clearly in my memory from some childhood book's chapter heading is a subtly shaded pencil sketch of a bird house, with a gabled roof and dowel perch, sitting sweetly atop a square peg post with flowers blooming at the base and butterflies fluttering about. It's a charming and cozy iconic visual, but I rarely give nest boxes a second thought while out hiking. The dilapidated state of this one stopped me in my tracks long enough to ponder some questions and provided a reason to look up information.
Is it merely semantics that distinguishes a bird house from a nest box? Are nest boxes like this one placed specifically for bluebirds? Why do bluebird nest boxes have a flat roof? Why don't I see boxes with pegs for perching? How come there aren't more different style nest boxes around? What happened to this box? With our weather incredibly mild since the spring of 2011, I doubt this damage was due to any storm. Did a raccoon tear this box apart? Did unknowing humans vandalize this box? Are these the remains of a bluebird nest or of some other bird?
I know there are different styles of nest boxes for different kinds of birds, even though this medium-sized one with a flat roof is the type I most often see in parks around here. While I don't normally link to commercial sites, this bird house supplier has a nice page of various man-made structures (they're not all boxes!) built to attract nesting birds. I've seen owl boxes at Elkhorn Slough, wood duck boxes at various places I can't recall offhand, and numerous bluebird boxes, including one lone bluebird nest box at Fort Ord in memory of Chuck Haugen, which ironically is one of two places I've ever actually seen a western bluebird, with the other place being Pinnacles.
With the question of which birds also utilize nest boxes placed out for bluebirds, I continued to search. Tree swallows have used them at Hastings Reserve. European starlings and house sparrows compete with bluebirds for nesting sites. Violet-green swallows and mountain chickadees use cammed bluebird nest boxes at James Reserve in SoCal. Are there other birds, too? I'll have to keep looking.
Steve at Blue Jay Barrens has a nice series of posts for bird box, eastern bluebird nest (Sialia sialis), and tree swallow nest. Keeping nest boxes takes dedication and regular maintenance.
