“Don’t fly, Mister bluebird, I’m just walkin’ down the road. Early morning sunshine, tell me all I need to know.” These lyrics from the Allman Brothers’ song, “Blue Sky” always come to mind when I step outside our office building in the springtime. We have several bluebird houses installed on the Extension grounds, and birds have been busily building nests the last several weeks. Despite my attempts to admire from a safe distance, I inevitably disturb them and they fly off.
The Eastern Bluebird (Siala sialis) is a native species of cavity nesting bird, which covers territory from central Canada all the way south to Texas and coastal Florida. The United States is home to two other native bluebirds, the Mountain bluebird (S. currucoides), residing in high plains from Alaska to the mountain southwest, and Western bluebird (S. mexicana), which lives in drier evergreen forests on the west coast, from southern Canada to Baja Mexico. In comparison photos, the bluebird species have redder bellies on the east coast and are progressively bluer as you move west.
Bluebirds’ striking color patterns make them a favorite of amateur birdwatchers and one of the easiest birds to identify in the field. Their brilliant blue is a trick of the eye, though—in reality, birds are unable to produce blue feathers. Flamingos and roseate spoonbills produce genuine pink feathers using pigments from their food (like shrimp), but bluebirds are actually gray. As described by Smithsonian wildlife biologist Scott Sillett, the blue is a “structural color” formed by the angles of sunlight and refraction from keratin, creating the illusion of a brilliant blue. I’ve always thought bluebirds seemed brighter blue on sunny, blue-sky days—turns out they probably are!
Bluebirds have overcome numerous threats to their populations over the last few hundred years in the United States. From habitat loss, fire ants (which attack nestlings), pesticides, and competition from introduced house sparrows and European starlings, bluebirds struggled for quite some time. Thankfully, their populations are now actually increasing and they are a “species of least concern.”
I noted about a year ago that someone in my neighborhood installed half a dozen bluebird boxes in our neighborhood park, and I’m betting that trend is multiplied exponentially around the country. Eastern bluebirds are a species of thrush, and are just one of many species that might utilize a nest box. In the wild, they are secondary cavity nesters. This means they wait for a primary cavity nester, like a woodpecker, to create a hole, then move in after it’s been abandoned. So, they are quite content to move into a prefabricated home built by humans.
For best success, bluebird boxes should be installed in areas with wide open, meadowlike conditions. They prefer to perch up high but fly down to forage for insects on the ground. Their preference for insects makes them a favorite of farmers and organic vegetable growers.
From ancient Chinese, Russian, and Native American mythology to folklore and music of the deep South, bluebirds hold a special place in the human imagination. The song and phrase “bluebird of happiness” reflects their cheery appearance and simple joy. In a quick online search of bluebird references in popular culture, I found more than 25 in the last 100 years. Something about the impossibility of a brilliant blue little bird on a spring day just feels uplifting and joyful. Even in the wistful song from the Wizard of Oz, Dorothy sings, “Somewhere over the rainbow, bluebirds fly.”
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