It wasn’t until we moved to the Sierra Nevada Foothills that I saw my very first bluebird. I soon discovered that our open fields and gardens with nearby woodlands make the near-perfect “edge environment” for these shy charmers.
Bluebirds are secondary cavity nesters, nesting in holes premade by woodpeckers and other creatures. But as more and more land is developed, we continue to demolish the old trees and wooden fence posts that once made possible an abundance of bluebirds and other cavity nesters.
European starlings and English house sparrows, brought from the Old Country, multiply quickly and out-compete bluebirds for the remaining nesting spots. Food, too, is scarcer and bluebirds now raise fewer thriving families.
THE HOUSING SHORTAGE: Each spring bluebirds frantically scramble and squabble in search of suitable nest sites. Put the right bluebird nest box (or boxes) in your yard and you may soon have eager occupants.
The entrance hole is critical-just big enough for bluebirds but too small for predators like starlings. Our western bluebirds need a 1-1/2 inch entrance hole and mountain bluebirds require a 1-9/16 inch hole. Don’t add a perch since this makes it easier for other birds to harass or attack the box’s occupants.
Look for a box with a hinged front or side for easy cleaning and to aid monitoring and eviction of bullying house sparrows. Bluebirds lay four to six blue or occasionally white eggs. House sparrows produce as many as five to seven cream-colored eggs with brown markings. Bluebirds sometimes nest twice but house sparrows can produce several clutches each year.
Bluebirds like 100 feet or so between their house and that of other bluebirds. Boxes spaced closer often attract tree swallows, another sought-after foothills bird. Bluebirds and swallows may quarrel over territory but eventually settle down to live in bug-gobbling harmony.
BUGS AND BERRIES: A healthy population of birds is one of the best friends a gardener can have, but you must first have bugs in order to feed bluebirds. Do away with bug- and bird-sickening pesticides. Bluebirds in turn are literal death on grasshoppers, flying insects, beetles, and caterpillars.
To further support bugs and the birds that depend on them, protect and plant more California natives. Many insects cannot or will not eat plants from distant lands.
Bluebirds are also gluttons for berries, so look for native species of these eye-catching, berry-producing shrubs and trees: elderberries, snowberries, gooseberries and currents, grapes, dogwood, Oregon grape, coffeeberry, hollyleaf cherry, manzanita, and toyon or Christmas berry.
LIQUID ASSETS: A family of bluebirds frolicking in a birdbath is the crowning touch to any garden. Bluebirds welcome a shallow, regularly-filled birdbath placed in the open so predators cannot surprise the bathers. Nearby trees or shrubs should afford a safe perch for drying off.
With a little help from their friends, bluebirds can continue to grace our fields and gardens. Learn more at www.nabluebirdsociety.org and http://extension.oregonstate.edu/catalog/pdf/ec/ec1571.pdf.
Find native plants and birdhouses of many types at the California Native Plant and Central Sierra Audubon Society sale October 15, Rocha Park, Jamestown. Watch for more details next week.
Vera Strader’s Sonora area yard is a National Wildlife Federation Habitat Garden. A dozen bluebird boxes welcome these voracious bug and berry eaters.