North America is home to an array of birds showcasing striking blue plumage. These vibrant birds add color to diverse landscapes across the continent. This article explores the biological mechanisms behind their color, identifies common blue birds in North America, and provides guidance for observing them responsibly.
The Science Behind Blue Feathers
The vivid blue seen in many bird feathers is not due to blue pigment. Unlike reds, yellows, and oranges, which are produced by pigments absorbed from a bird’s diet, blue coloration results from structural properties within the feathers. Bird feathers contain microscopic structures, often made of keratin protein, interspersed with air pockets. When light strikes these nanostructures, shorter blue wavelengths are scattered and reflected, while longer wavelengths like red and yellow are absorbed by an underlying layer of melanin.
This phenomenon is known as structural coloration. It arises from the physical arrangement of materials rather than chemical compounds. If a blue feather is crushed, the structural arrangement is destroyed, and the blue color disappears, revealing the feather’s underlying brown or gray hue. The specific size and arrangement of these air pockets and keratin structures can produce various shades of blue.
Common Blue Birds of North America
North America hosts several blue bird species, including the Blue Jay, Eastern Bluebird, Indigo Bunting, Mountain Bluebird, and Lazuli Bunting.
Blue Jay
The Blue Jay (Cyanocitta cristata) is a large songbird found across eastern and central North America, from southern Canada to Florida and northeastern Texas. Its plumage is predominantly bright blue on its back, wings, and tail, with a white chest and underparts, a blue crest, and a black, U-shaped collar. Blue Jays inhabit deciduous and mixed forests, and are also common in residential areas, especially where oak trees are present. While largely resident, some northern populations may migrate south during winter.
Eastern Bluebird
The Eastern Bluebird (Sialia sialis) is a medium-sized thrush found east of the Rocky Mountains, from southern Canada to the Gulf Coast and into Mexico. Males display a vibrant blue upper body, a rusty red breast, and a white abdomen. Females share a similar pattern but are duller, appearing grayer with blue on their wings and tail. These birds prefer open habitats such as meadows, orchards, farmlands, and suburban parks with scattered trees and low ground cover. Eastern Bluebirds are cavity nesters, using natural tree hollows or man-made nest boxes.
Indigo Bunting
The Indigo Bunting (Passerina cyanea) breeds across eastern North America from southern Canada to northern Florida and eastern Texas. The male is a vibrant, uniform blue during the breeding season, appearing almost black in poor light, while the female is a dull brown with faint streaking. Their habitat includes brushy forest edges, open deciduous woods, and farmland. These buntings are migratory, spending winters from southern Florida through the West Indies and Central America to northern South America.
Mountain Bluebird
The Mountain Bluebird (Sialia currucoides) is found in the open country of western North America, breeding from Alaska south through British Columbia. The male has striking sky-blue plumage across its entire body, a lighter blue on its throat and breast, fading to white on the abdomen. Females are gray-brown with pale blue on their wings and tail. These birds inhabit higher elevations, including alpine meadows and clearings, and also use lower-elevation grasslands, plains, and farmlands. Mountain Bluebirds are the most migratory of the bluebird species, with northern populations moving south for the winter.
Lazuli Bunting
The Lazuli Bunting (Passerina amoena) is found in western North America, breeding from southwestern Canada south through the western U.S. states. Male Lazuli Buntings have a bright blue head and back, white wing bars, a rusty chest, and a white belly. Females are brownish-gray with a buff breast and blue on their wings and tail. Their habitats include brushy areas with open grassy ground, such as scrub oak patches, chaparral, and streamside thickets. Lazuli Buntings migrate to southeastern Arizona and Mexico for the winter.
Attracting and Observing Blue Birds
Creating a welcoming environment can encourage blue birds to visit and even nest in a backyard. Providing appropriate food sources is a primary step. Bluebirds primarily consume insects during warmer months and shift to berries in fall and winter. Mealworms are an effective food source and can be offered in open tray feeders. Bluebirds do not typically eat seeds, but may consume sunflower hearts or suet during colder periods.
Offering fresh water is important; a shallow bird bath can draw them in. Planting native berry-producing trees and shrubs provides a natural food source that persists into winter. Choices include junipers, dogwoods, sumacs, hollies, serviceberries, elderberries, and highbush blueberries. Leaving dead trees or limbs, if safe, provides nesting and roosting sites for cavity-nesting bluebirds, or perches for hunting insects. Installing properly designed nest boxes can also provide nesting habitat.
Observing blue birds requires patience and adherence to ethical guidelines to minimize disturbance. Maintain a respectful distance, especially during nesting season, to avoid causing stress. Using binoculars or a spotting scope allows for close-up views without intrusion. Move slowly and quietly, avoid sudden movements, and refrain from using recordings of bird calls, as these can disturb birds. Stay on designated trails and respect private property to ensure habitats remain undisturbed.