Many careers and hobbies begin because one person has influenced another. Ann McBride and Patty Evans serve as prime examples of this. Upon reading a 2001 article in the Sacramento Bee, they learned of a woman named Barbara Moore, who in 1980 took it upon herself to make nesting boxes for bluebirds with a goal of monitoring their population. She placed 120 boxes throughout Prosser and Russell Valley, returning every spring to count and record the eggs.
McBride and Evans were inspired and eventually joined Moore on her bluebird adventures, learning everything they could about her methods and the ways of the beautifully bright blue bird. “We were like little puppies, following behind Barbara on her bluebird walks,” said McBride. For the past two decades, McBride and Evans have continued Moore’s tradition, not in Prosser and Russell Valley, but rather in the Martis Valley and Kyburz Meadow areas, where they have helped to increase the population of these feathered friends.
McBride shared her experiences with a lecture at the Truckee Library in May, during which she discussed the main distinguishing characteristics between the two types of bluebirds found in our region. “The mountain bluebird (Sialia currucoides), prefers higher elevations, up to 9,000 feet, in our area,” she said, noting that there have been sightings near Castle Peak. “The western bluebird (Sialia mexicana) inhabits lower elevations.”
Although they didn’t construct their boxes, as their mentor Moore had done years earlier (they left that to builder Dave Owen), McBride and Evans distributed them and have continued to maintain them and count the eggs inside year after year.
As is typical of many birds, the male bluebird is much brighter than the female. The male is easily spotted by its bright blue-sky color. The female is grayish with mere touches of blue on its back and wings.
The bluebird carries the sky on his back. ~ Henry David Thoreau, 1852
Bluebirds are labeled in a classification called cavity nesters. “They build their nests in cavities made by woodpeckers or in deep knotholes,” said McBride, noting other such birds include chickadees, nuthatches, and tree swallows. To create their nests, they gather sticks, grass, and feathers — typically from geese — and sometimes shavings from junipers. Before they build, however, bluebirds “shop” for the perfect location. Shopping for the nest occurs in early spring, usually in March. The male picks a cavity, with the female either agreeing to the choice or waiting for another option.
A big consideration in “finding a home is the difference in the temperament of birds,” said McBride. “The bluebird is very docile, whereas the tree swallow is not.”
The tree swallow, she said, a more aggressive bird, will choose its nest first, defending it from a bluebird that might desire the same one. Once the tree swallow is settled in, a bluebird can then choose its own home. For this reason, McBride and Evans place two boxes approximately 3 to 10 feet apart, thereby allowing a tree swallow to inhabit one house while a bluebird takes residence in the other. But like anyone searching for a home, it comes down to location, location, location: Bluebirds prefer open areas like meadows, so placing a bluebird box in a thick forest won’t attract them. Chickadees, however, would be glad to move in to a forest abode.
Humans often desire a flat plot of land on which to build their homes, but bluebirds, not so much. McBride shared the story of a woman who once accompanied her on a bird walk, with a level in-hand, wanting to ensure the boxes were even. “They don’t care,” Evans reportedly told the woman. “Birds will place nesting materials in a way that levels a slope. Consider natural cavities, they’re not level either.”
The diet of mountain bluebirds directly relates to the timing of nesting. Since they eat insects and caterpillars, the birds wait until the weather warms and the bugs come out. Only then will the mountain bluebird find a home and create a nest. After about two weeks of incubating in the new nest, four to six pale blue eggs will hatch. On average, the mountain bluebird produces one brood of chicks, but McBride and Evans have occasionally found two hatchings and, on a rare occasion, even three.
McBride recalled once observing a box that was visibly rocking from all the activity inside. At the time, it was housing at least five chicks, which McBride describes as looking like an “orange pencil eraser with a beak, the chick no bigger than the tip of your little finger.”
Following a three-week feeding frenzy, the young birds fledge, leaving the comfort of their home, although McBride and Evans have occasionally seen parents continuing to feed their brood outside the box on nearby tree branches. For how long, they don’t know, but they’ve been pleased to witness parents caring for their young.
Once the birds fledge in July and August, the mountain bluebird leaves the Tahoe area in October for warmer climes. Unlike the tree swallow, which flies as far south as Costa Rica, the mountain bluebird finds its winter home close by, right next door in our border state of Nevada. The hardy chickadee, on the other hand, remains in the Truckee/Tahoe region all year.
“The birds don’t really need us, but we absolutely need them,” Evans said of the role the mountain bluebird plays. “We need birds as an essential link in the ecology of a healthy world. But more personally as a necessary part of our life in the mountains. The amazing beauty of their feathers, nests and eggs. Such joy from very tiny very strong natural beings.”
For further information on mountain bluebirds or instructions on how to create your own bluebird box, check out the California Bluebird Recovery Project, cbrp.org. And check out the library’s upcoming events for more talks on the natural world.