Small blue birds captivate observers with their striking coloration and lively presence. Their vibrant hues stand out in various environments, from backyard gardens to open woodlands. This article explores the science behind their blue feathers, common species, and how to attract and observe them.
The Science of Blue Feathering
The blue color in many birds’ feathers is not due to blue pigments. Instead, it is a structural color, resulting from how light interacts with the feathers’ microscopic structure. Within the feather barbs, tiny air cavities or keratin particles are arranged to selectively scatter blue light. Longer wavelengths, such as red and yellow, pass through this layer and are absorbed by an underlying layer of melanin, intensifying the reflected blue.
This phenomenon is similar to how the sky appears blue due to the scattering of sunlight by molecules in the atmosphere. If a blue feather is crushed, its structural integrity is destroyed, and the blue color disappears, revealing the underlying melanin. In contrast, colors like red and yellow in birds are often produced by pigments, which are chemical compounds obtained from their diet that absorb certain wavelengths of light and reflect others.
Common Small Blue Birds and Their Features
The Eastern Bluebird, common across eastern North America, measures about seven inches long. Males display vivid deep blue upper parts, a rusty throat and chest, and a white belly. Females are generally duller, with grayish upper parts and bluish wings and tail. They favor open country, farms, and orchards.
The Indigo Bunting, a North American species, is typically between 4.5 and 5.1 inches long. Breeding males are brilliant blue, though their color can appear dark or blackish in poor light. Females and non-breeding males are predominantly brown with faint streaking, sometimes exhibiting subtle blue tinges on their wings or tail. They prefer brushy forest edges, open woodlands, and farmland.
The Lazuli Bunting, found in western North America, is similar in size to the Indigo Bunting, ranging from 5.1 to 5.9 inches. Males are sky-blue on their heads and backs, with a rusty breast, white belly, and noticeable white wing-bars. Females are grayish-brown with touches of blue on their wings and tail, and usually display two thin, pale wing-bars. This species often inhabits brushy areas and streamside shrubs.
In Europe, the Eurasian Blue Tit is about 4.5 inches long. It has a distinctive blue cap, a white face with a thin black eye-stripe, yellowish underparts, and greenish upperparts, with blue wings and tail. These birds are frequently seen in woodlands, gardens, and parks.
The Florida Scrub-Jay, unique to Florida, is larger than the bluebirds, measuring 9 to 11 inches. It has a blue head, wings, and tail, with a gray back and underparts, and a whitish forehead, notably lacking a crest. These jays are found exclusively in scrub oak habitats.
Ecology and Behavior of Small Blue Birds
The diets of small blue birds vary seasonally. During warmer months, many species primarily consume insects like grasshoppers, crickets, and spiders. As temperatures drop, their diet shifts to berries and fruits, including wild grapes, dogwood berries, and sumac. This flexibility allows adaptation to changing food availability.
Nesting habits differ among these birds. Eastern Bluebirds are secondary cavity nesters, often utilizing old woodpecker holes or nest boxes. Females typically construct nests using grasses and pine needles, often lined with finer materials. Indigo and Lazuli Buntings build open-cup nests hidden in dense shrubs or low trees. Eurasian Blue Tits also nest in holes, including tree cavities and nest boxes.
Many small blue bird species are migratory, moving between breeding and wintering grounds. Indigo Buntings, for example, migrate at night, using stars for navigation. Other species, like the Florida Scrub-Jay, are non-migratory, remaining in their habitats year-round. While some species, like the Indigo Bunting, are solitary foragers during breeding season and form flocks in winter, others, like the Florida Scrub-Jay, exhibit cooperative breeding where young from previous broods help raise new offspring.
Attracting and Observing Small Blue Birds
Attracting small blue birds involves providing suitable food and habitat. Offering live or freeze-dried mealworms in tray or dish feeders can be effective, as these birds are not typically attracted to seeds. Planting native berry-producing shrubs and trees, such as dogwood or wild grapes, offers a natural food supply, especially when insects are scarce. Avoiding pesticides is important, as it protects their primary insect food source.
Creating a bird-friendly habitat includes maintaining open areas with scattered trees and minimal underbrush, allowing space for foraging. Keeping grass trimmed helps them spot ground-dwelling insects. Providing a clean water source, such as a bird bath, is beneficial. For cavity-nesting species like Eastern Bluebirds, installing nest boxes can encourage them to take up residence.
Observing these birds ethically involves minimizing disturbance. Maintain a respectful distance, especially around nesting sites, and avoid approaching or flushing birds. Refraining from using call playbacks prevents undue stress or disruption. Staying on designated trails and keeping pets leashed helps protect their habitats and ensures a positive experience.