There are two different kinds of bird colors: pigment-based, and structural. White, blue, green, iridescent and ultraviolet birds derive their color from the structure of their feathers, specifically from the protein keratin in their feathers (also the chief constituent of hair, nails, horns and hoofs).

In the case of the bluebirds (and Blue Jay), the keratin reflects and scatters incoming light, reflecting the shortest wavelength (blue). The blue of the sky results from a similar scattering of light in the atmosphere.

Bluebirds are from the same family as the American RobinŠthe thrush (Turdidae) family. Like the Robin, bluebirds have powder-blue-colored eggs. Their bills are narrow for catching insects, their main diet, and wild fruits and berries during the winter months. Unlike the robins, bluebirds nest in cavities with nests made of finely woven grasses or sometimes of pine needles.

The three species of bluebirds, Eastern Bluebirds (Sialia sialis), Mountain Bluebirds (Sialia currucoides) and Western Bluebirds (Sialia mexicana), are among more than 300 thrushes worldwide. Similar to other species in the thrush family, bluebirds devour large quantities of insects. In the fall and spring, bluebirds in cooler climates switch from insects to berries as they begin a migratory flight to warmer climates.

With the introduction of the more aggressive House Sparrow and European Starling into North America in 1852 and 1880, competition for nesting cavities became fierce. Unfortunately, the sparrows and starlings would often evict, and sometimes kill, the more timid bluebirds.

Then came the replacement of wooden fence posts with metal posts. The old wooden posts were often used as nesting sites by the bluebirds when the posts rotted out. Natural cavities found in dead trees also became scarce as removal of these "unsightly" trees became commonplace. Farming practices, including removal of fence rows and application of pesticides, and expanding urban sprawl destroyed viable habitat and poisoned the bluebird's primary source of food: insects. Climate changes, too, have created problems for bluebirds; excessive heat or sudden winter storms have historically devastated populations of bluebirds unable to successfully cope with the sudden severe weather.

By 1977, according to the late Dr. Larry Zeleny, often considered the father of the organized bluebirding movement, the Eastern Bluebird population, found east of the Rockies down to central Mexico, had declined more than 90 percent since the early 1900s. Western Bluebirds, found in the western United States and Canada, and Mountain Bluebirds, found above 7,000 feet in central and western North America, were also declining.

Zeleny's writings, including a National Geographic article about the plight of North American bluebirds, and his founding of the North American Bluebird Society (NABS) in 1978, inspired millions of people to establish bluebird trails and get organized into community, state, or provincial groups.

Thanks to the efforts of bluebird conservationists across the continent, this alarming trend has been reversed in less than two decades. It was human blunder and unwise development that led to the precarious situation in which the three bluebird species found themselves, so it's appropriate that a grassroots bluebirding movement has prevented these three species from landing on the Endangered Species list.

According to the Breeding Bird Survey (BBS) of the US Geological Survey, between the period of 1976 and 1996, Eastern Bluebirds' have experienced a population increase of about 5% a year, Mountain Bluebirds a 2% increase a year, and Western Bluebirds decline has been at least halted, as the BBS data now indicate no significant further decline in that population. However, in some states, like California, the Western Bluebirds continue their struggle for survival. Other cavity-nesting species, like the Purple Martin, also benefit from a similar conservation movement.

Since 1978, over a million bluebird nest box plans have been distributed by the 3,500-member NABS and 20,000-member affiliated state and provincial organizations. The Camp Fire Boys and Girls have promoted their "Project Save the Bluebird," and numerous state nongame wildlife conservation programs provided resources for bluebird conservation. Schools across North America have long utilized the hands-on aspect of bluebird conservation, weaving habitat, bird migration and bluebird life history into elementary and middle school life science curriculum.

 

Mister bluebird on my shoulder, It's the truth, it's actual, Ev'rything is satisfactual. "Zip-a-Dee-Doo-Dah" Lryics by Ray Gilbert, 1939, from Song of the South, Walt Disney Productions

From schoolchildren to retirees, individuals have joined together to construct one of the largest networks of trail systems in the world to help the bluebirds and other native cavity-nesting species that also that also make their homes in boxes. Bluebird lovers replaced the lost cavities with well-designed nest boxes, erected bluebird trails of five or more boxes, maintained a regular monitoring program, and shared a wealth of information on bluebird conservation and management at the end of each nesting season, leading to a rebound of the bluebird population.

As the late birding expert Roger Tory Peterson often commented with respect to the close human interaction with bluebirds, perhaps the bluebirds, in their acceptance of human interaction, realize that human involvement has helped them survive.

Free-lance writer/author/photographer John Ivanko '88 BBA is co-executive director of NABS. He and his wife, Lisa Kivirist, own and operate Inn Serendipity, a bed and breakfast in Browntown, Wisconsin, where one of their three bluebird nest boxes fledge two broods of Eastern Bluebirds annually.

The Transcontinental Bluebird Trail