By David Cronenwett
Around March 15th each year, I keep my eyes open, scanning nest boxes as I drive past the Ear Mountain trailhead on the Rocky Mountain Front. It is then, like clockwork that the first Mountain Bluebirds (Sialia currocodies) show up in the country. This month in Montana is mostly an extension of winter; blizzards, high winds and arctic cold snaps are common events. Yet there they are; vivacious, cerulean birds in a landscape that is still mostly dormant and lifeless. Their presence optimistically speaks to the imminence and renewal of spring. Three species of bluebirds spend part of their life cycles in our state; the Western Bluebird (Sialia mexicana) in the northwest and the Eastern (Sialia sialia) in the far southeast. But it is the “Mountain Blue” that dominates in Montana, both on the land and in the hearts of people.
These birds are a type of thrush, related to robins and are similarly gregarious and comfortable around civilization. Their breeding habitat ranges from northern Alaska, down the spine of the Rockies roughly to northern Utah, west to the Cascades and east toward the Dakotas. The overall coloring of the male can be best described as a reflection of the sky, an astonishing, brilliant blue, while females are more muted and subtle. They are a cavity nesting species; in the wild, the birds will search for an abandoned woodpecker hole and occupy it. But anymore, the human-manufactured nest box has become an important part of Mountain Bluebird ecology and survival.
In recent decades, the Mountain Bluebird has seen significant population declines due to a host of factors; the removal of standing dead trees which woodpeckers use for nesting, fire suppression in Montana’s forests has created unfavorable habitat conditions (too many small diameter trees, too close together) and competition for nesting sites with aggressive, non-native species like Starlings and House Sparrows began to take a toll on bluebirds. The bird’s habit of feeding on the ground has also made them particularly susceptible to predation by domestic cats. But the striking beauty of the species, their ease around humans and the fact that they will readily use nest boxes quickly inspired a culture of bluebird aficionados and led to a remarkable recovery.
Bud and Violet Olsen have lived on their ranch along the Teton River since 1949. They purchased the original 800 acres just a few years after Bud returned from the European theatre of WWII. And they are certifiable Bluebird advocates. About 20 years ago, Bud decided to pick up the cause and build nest boxes. He estimates he’s made about 150 or more of them, about 80 of which are in Teton County. A lot of thought went into Bud’s design; considerations for size, entry-hole diameter, drainage and ease of cleaning are all present as is the distinctive “Bench-Cross” brand he finishes each box with.
When I ask him “Why Bluebirds?” Bud, who is in his early nineties, responds with a smile, “They’re so vibrant.” It is easy to understand why this joy-inducing creature has inspired many organizations and individuals to action. There are several “bluebird trails” crisscrossing Montana; stretches of highway and rural routes lined with nest boxes. Many of them are maintained by volunteers; they are cleaned, repaired and information about nest success is recorded to track population trends over time. A portion of one such road, Montana 434 near Wolf Creek, was formally renamed in 2003 after Bluebird enthusiasts Tom and Pat Matsko, who founded the Mountain Bluebird Trails Club in 1980. Today, the organization maintains over 200 such trails in the state.
With such enthusiasm, the future of bluebirds, including the Mountain species, looks bright. I find one attribute particularly interesting about them: the color blue, which is so enchantingly vivid, is actually an illusion. This color is a result of tiny bubbles of air within the barbules of their feathers that refract the blue spectrum of visible light to our eyes. This is why on overcast days, the birds can appear more drab, as they do if backlit by the sun. Under magnification, the feathers of these birds are actually gray, a result of pigments called melanins. So, the brilliant color for which these birds are named and loved is actually something of Nature’s sleight-of-hand. But we are still universally moved when we see Mountain bluebirds, particularly in March; like joyful pieces of sky, in a landscape that is longing for spring.