In the vibrant realm of birds, few plumage colors invoke a sense of wonder, like the mesmerizing blue tone.
Blue birds can be found in vast areas of the planet, from tropical rainforests to local meadows and backyards. Each species shows unique adaptations and characteristics that help them survive in the ever-changing, challenging world.
Regarding bird plumage colors, most birds get their colors from pigments produced in the body or from food. However, birds with blue plumage don’t follow that agenda. There isn’t a blue pigment for birds, so how does the blue color come about?
The answer lies in the structure of their feathers and the resulting physics. The blue we see on birds is made through light scattering. During light scattering, visible light waves interact with nanostructures in the feather structure made of air and the protein keratin.
When the light reaches the feathers, it encounters the nanostructures. Most light wavelengths are absorbed and pass through the feathers. The nanostructures are similar in size to the blue wavelength of light, which means the blue light can’t pass through and is reflected as a result. That is why we see the feathers as being blue.
But then you may wonder why birds have so many shades of blue. That is because different feathers have different keratin structures, which reflect light differently, creating different intensities of blue.
A blue bird may look greyer under low light conditions on cloudy days because of the lack of light reflecting off the keratin structures.
Now that you know more about the science of why we see blue feathers, we can dive into the rest of the article, where we look at the Sialia genus of bluebirds and other beautiful types of blue birds found in North America.
1. Eastern Bluebird (Sialia sialis)
The Eastern Bluebird is a type of blue and orange bird. Males have a blue head and upper parts, with dark grey wing tips. On the underside, they have a deep orange throat, chest, neck sides, and flanks, along with a white belly.
Females are greyish on the upper side, with blue on the wings and tail. They also have a white belly and orange on the chest, flanks, and neck sides.
They inhabit fields, agricultural lands, orchards, pastures, open woodlands, and suburban environments.
They feed on insects and spiders throughout the year. In winter, they also eat fruit.
Eastern Bluebirds are resident in most of their range in the eastern United States, Mexico, and Central America.
They are migratory in the northeastern United States and southeastern Canada, where they only occur during summer. They winter in the southeastern United States and Mexico.
2. Western Bluebird (Sialia mexicana)
The Western Bluebird males have a dark blue head, throat, back, wings, and tail. The chest, flanks, and upper back are dark orange, while the belly is grey.
The females are dark grey above, with blue on the wings and tail. Below, they have an orange chest and flanks, a buffy throat, and a grey belly.
They occur in fields with scattered trees, open woodlands, and woodland edges.
Their diet mainly comprises insects during summer. In winter, they eat many fruits and seeds.
The Western Bluebird is distributed on the western side of North America. They remain year-round in most of their range, but birds in the interior and northern parts are migratory – moving south to the southern United States and Mexico for winter.
There is also some altitudinal migration as birds move from high to low elevations in winter – particularly in mountainous areas.
3. Mountain Bluebird (Sialia currucoides)
The Mountain Bluebird male is a stunning electric blue bird with a white belly. The wings and tail are darker, the underside is paler, and the wing and tail tips are darker grey.
The female is grey-brown with lighter underparts and blue on the wings and tail. They also have a whitish eye ring, and in some cases, females have rufous on the chest.
Mountain Bluebirds occur across western North America. They are migratory, occurring in northwestern North America during summer and as far south as central Mexico in winter. They are residents in the center of their range.
They occur in open habitats such as meadows, grasslands, prairies, tundra edges, alpine hillsides, recently cleared and burned areas, and pastures.
In terms of diet, they eat insects almost exclusively. They supplement their diet with spiders, fruits, and seeds in winter.
4. Blue Grosbeak (Passerina caerulea)
The Blue Grosbeak is a large bunting with deep blue plumage, blackish wings, and tail, a small black face mask, a sizeable two-toned silver and black beak, and rufous and buffy wing bars on breeding males.
Males in non-breeding plumage have a mix of blue and brown throughout the body. Females are light brown, with a bluish back, dark wings with rufous or buffy wing bars, and a pale belly.
They live in overgrown fields, forest edges, hedgerows, deserts, streamside thickets, savannas, and forests.
They occur in the southern and central United States and northern Mexico during summer and in southern Mexico and Central America during winter. They are resident in parts of Mexico and Central America.
Their diet primarily consists of insects, but they also eat spiders, seeds, grains, and snails.
5. Indigo Bunting (Passerina cyanea)
The Indigo Bunting male in breeding plumage is a brilliant, almost entirely blue bird with dark wings and a black and grey beak. In non-breeding plumage, the males are browner with hints of blue throughout the body.
Conversely, females are brown on top with darker wings and pale whitish-brown underneath with dark streaking. They also have a bluish tail and a whitish throat.
They inhabit forest edges, thickets, and brushy and weedy fields during summer. When migrating, they occur in open grasslands and dense trees. In winter, this species inhabits orchards, fields, savannas, and croplands with weeds.
They occur in eastern North America and parts of the southwestern United States during summer. This species is migratory, wintering in Mexico, Central America, the Caribbean, and northern South America.
During summer, Indigo Buntings feed on insects, spiders, seeds, and berries. They mainly feed on grass seeds, insects, and buds in winter.
6. Steller’s Jay (Cyanocitta stelleri)
Steller’s Jay is a large black and blue bird with a prominent crest. The front portion of their body is black, fading into dark blue on the rest of the body. There is geographic variation across their distribution, with the coastal individuals being the darkest with blue marks on the crest.
Birds from the interior have white streaking on the crest and chin, along with a white mark above the eye. In Central America, they are generally more blue overall, with contrasting white marks surrounding the eyes.
They are distributed across western North America from Alaska into Central America as far south as Nicaragua.
They inhabit forests, woodlands, campgrounds, picnic sites, parks, and yards throughout the year.
Their diet comprises insects, fruits, seeds, nuts, small mammals, reptiles, eggs, nestlings, scraps, and suet.
7. Black-throated Blue Warbler (Setophaga caerulescens)
The Black-throated Blue Warbler is a stunning migratory warbler. The males have a white underside which contrasts significantly with the dark blue head and back and black face, throat, flanks, and wings.
Females are olive-brown on the upper side with buffy underparts. They have a whitish eyebrow stripe and white surrounding the eye. Both sexes have a distinct white wing patch.
They inhabit dense deciduous and mixed forests and woodlands during the breeding season. While migrating, they occur in woodlands, yards, and parks. In winter, they occur in tropical forests, plantations, and woods.
This species breeds in the eastern United States and southeastern Canada. They spend the winter months in the Caribbean and Central America.
They feed on insects and spiders but supplement them with fruit, nectar, and seeds in winter.
8. Blue Jay (Cyanocitta cristata)
The Blue Jay is a blue and white bird with a large crest. Their upper parts are bright blue, and the underparts are greyish-white. They have a distinct black necklace, white wing bars, and black barring on the wings and tail. The face is white with black in front of the eye, and the crest is grey-blue.
They occur throughout the year in the eastern United States and southern Canada. Individuals in the far north of their range migrate south for winter.
They live in woodlands, forests, parks, and yards.
Their primary food sources are insects, nuts, fruits, and seeds. They sometimes feed on grains, eggs, and nestlings.
9. Cerulean Warbler (Setophaga cerulea)
The Cerulean Warbler is a distinct migratory warbler, with the males showing a sky-blue back broken by black streaks. The wings are dark, the rump is greyish-blue, and the tail is blue and black. They have a white throat and belly, a narrow blue necklace, and blue streaks on the flanks.
Females are dull greenish-blue on the upperside with a whitish eyebrow stripe, faint streaking on the flanks, and a yellow tint on the underparts. White wing bars are present in both sexes.
They live in deciduous forests during summer, tropical forests, plantations, and scrubland during migration, and evergreen woodlands, forests, and shade-grown coffee plantations at their wintering grounds.
This species breeds in the northeastern United States. In winter, they occur in northern South America on the eastern side of the Andes from Bolivia to Venezuela.
They primarily feed on insects and eat plant matter in winter.
10. Florida Scrub Jay (Aphelocoma coerulescens)
The Florida Scrub Jay is the only endemic bird of Florida in the United States. It can be found nowhere else because of its specific habitat requirement. It is only found in the endemic Florida scrub habitat, which is composed of low oak scrub.
It is a long-tailed jay with a blue head, wings, and tail, a grey back, a grey belly, a whitish forehead, a blue neck, and a white throat surrounded by a blue-grey bib and greyish-white underparts.
They feed on acorns, insects, berries, seeds, small mammals, birds, and reptiles.
11. Lazuli Bunting (Passerina amoena)
The Lazuli Bunting is named after the bright blue head and throat seen on breeding males. In addition, they have blackish-grey feathers on the back and wings, while the rump is blue, the tail is dark with a bluish tint, and white wing bars are present.
On the underside, they have a white belly and an orange chest. The bill is two-toned, with black on the top and greyish on the bottom. In non-breeding plumage, the males look similar, but their upper side is mottled in brown and blue.
The female is greyish-brown on the upper side and head with a grey-blue rump, blue tinges on the wings and tail, and buffy-white wing bars. We see an orange chest and a whitish-grey belly and throat on the underside.
They live in brushy hillsides, ravines, wooded valleys, thickets, scrubland, weedy pastures, agricultural areas, yards, and along streams.
They are migratory, breeding in the northwestern United States into Canada and wintering in Arizona and western Mexico.
This species feeds on insects, spiders, seeds, and fruits.
In North America, there is a good variety of blue birds. Blue birds can be found throughout most of North America in many habitats, particularly in summer when the migratory species return to their breeding grounds. If you live within their ranges, you may be lucky enough to see more than one majestic blue bird visiting your yard.
Blue birds differ from other birds in the way the color is formed. Instead of being produced through pigments, blue is a structural color made with light. The blue color we see is created through the interaction of light and nanostructures in the feathers consisting of air and keratin that reflect blue light.
Next time you see a species of blue bird, note how the color looks different in variable lighting conditions, and you’ll see physics in action.
Whether you’re an avid birdwatcher or a casual observer of the natural world with an interest in birds, you’ll be taken aback by the beauty that is blue birds.