Sunday, September 23, 2012

nest box for western bluebird ~ 09/23/12 ~ Toro Park

nest box for western bluebird
nest box for Sialia mexicana

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 ReserveEuropean starlings and house sparrows compete with bluebirds for nesting sitesViolet-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.


Neil Kelley said...

We had a bluebird box in our yard when we lived in Palo Alto, and both years that we were there it was occupied by Bewick's Wrens. I'm pretty sure they hatched second broods both years, though I'm not sure if all broods fledged (at least some did though). I think we left the box there so hopefully it was used this year again!

I never saw a Western Bluebird in our yard, although they are/were abundant on the Stanford Campus near lake Lagunita and the Arastradero Preserve nearby.

Katie (Nature ID) said...

Hey, Mr. Dad. Great to hear from you. Do you miss CA? I imagine you're experiencing a whole different world of nature out there. I had to look up Bewick's Wrens. I bet they were fun to watch and hear. I'll ask a friend of mine if her folks' house in Palo Alto has nest boxes.

randomtruth said...

Not sure about your area, but lots of western bluebirds nest along the east side of the Santa Cruz Mtns. Edgewood Park has a number of nesting boxes for them that are maintained by volunteers and ornithologists. The park even does dedicated docent-led bluebird walks during the summer. If you have bluebird pops down there, you may find similar programs near by.

Katie (Nature ID) said...

Hi, Ken. From the information I found (dated 10-20 years ago), it looks like western bluebirds do not nest right along the coast anymore due to development and climax Monterey pine forest. They're still common inland starting about 12 miles, like where I found this nest box. I'll keep my eye out for bluebird programs through the several park systems we have in the area. Thanks.