Bluebirds are a captivating species of medium-sized birds native to North America, belonging to the genus Sialia within the thrush family (Turdidae). They are one of the few thrush genera found in the Americas. These charming birds are admired for their vibrant colors and unique behaviors, making them a popular subject of observation for bird enthusiasts.
The bluebird’s diet mainly consists of insects and small invertebrates, although they also consume berries and fruits, classifying them as omnivorous. There are three primary species of bluebirds: Eastern Bluebird, Western Bluebird, and Mountain Bluebird. The male Eastern Bluebird displays an eye-catching combination of royal blue and red-brown plumage.
These stunning creatures raise two to three broods annually, laying an average of 4 to 6 eggs per clutch. Bluebirds often nest in natural tree cavities or artificial nesting boxes, making them a symbol of suburban gardens and rural landscapes alike.
Through understanding and appreciating these beautiful avian species, we can further the conservation of their habitats and cherish their continued presence in our world.
What are Blue Birds?
Bluebirds are a group of medium-sized, primarily insectivorous or omnivorous birds belonging to the genus Sialia, within the thrush family (Turdidae). These attractive birds are known for their beautiful blue plumage, which makes them a sought-after species for birdwatchers and nature enthusiasts alike.
There are three species of bluebirds found in North America: the Eastern Bluebird (Sialia sialis), the Western Bluebird (Sialia mexicana), and the Mountain Bluebird (Sialia currucoides). Each of these species has distinct features and habitats.
Eastern Bluebird (Sialia sialis): The most widespread of the three, its range extends from eastern North America south to Nicaragua. Eastern Bluebirds often nest in birdhouses along designated “bluebird trails,” making them a familiar sight in many rural and suburban areas. They lay an average of 4 to 6 eggs per clutch and can brood two or three times in a year.
Western Bluebird (Sialia mexicana): Found in the western parts of the United States and Mexico, the Western Bluebird has a diverse range of habitats. They can be observed in open woods, farmlands, and even suburban gardens. Like their eastern counterparts, Western Bluebirds also benefit from human-made nest boxes.
Mountain Bluebird (Sialia currucoides): The Mountain Bluebird inhabits the high-altitude regions of western North America, from Alaska to Mexico. This species is the most migratory of the bluebirds, but some populations remain non-migratory in parts of the West and Southwest. Their vibrant, bright blue color is a striking feature against the backdrop of their alpine homes.
As members of the thrush family, bluebirds share similarities with other thrushes like the American Robin, Varied Thrush, and Wood Thrush. Their diet mainly consists of insects, but they consume fruit and seeds when insects are less abundant. This versatility in their dietary preferences contributes to their adaptability and success across various habitats.
Habitat and Distribution
North America Concentration
Bluebirds are primarily found in North America, with a significant presence in the southern United States, Canada, and Mexico. They prefer open country with scattered trees, providing ample space to forage and nest. These birds often inhabit woodlands, parks, and backyards.
Presence in Eastern Regions
Eastern Bluebirds (Sialia sialis) are prevalent in the eastern half of North America, stretching from the Canadian provinces down to Mexico. Their range spans from Missouri and Pennsylvania in the north to Texas and the eastern coast of Mexico in the south. Eastern Bluebirds are common in open woodlands and other environments with a mix of trees and open spaces.
Western and Rocky Mountains Regions
Two other species of Bluebirds can be found in the West and the Rocky Mountain regions. The Western Bluebird (Sialia mexicana) inhabits the western part of the continent, primarily in the southwest. Meanwhile, the Mountain Bluebird (Sialia currucoides) resides in the higher elevations of the Rockies and other mountainous areas.
Bluebirds’ migration patterns depend on their latitude and the availability of food sources. In general, their movements are influenced by seasonal temperature changes and the presence of suitable nesting sites. Some Bluebirds might not migrate if they can access enough food sources in their range. However, others may travel south to find milder climates during the winter months, especially those living at higher latitudes or in colder regions.
Nesting and Breeding
Eastern bluebirds prefer nesting sites that are in natural or artificial cavities. Both cavities can contain a crafted nest platform built by the female. She uses grass, twigs, and bark woven into a loose cup-shaped structure. Bluebirds have been known to occasionally nest outside cavities, such as in gutters that appear enclosures.
Bluebirds begin scouting for nest boxes as early as late February, depending on the region and weather conditions. If favorable, they may continue nesting into August or even September. The breeding season typically starts in the spring.
During the courtship period, the male and female engage in various displays and songs. Once paired, the female focuses on building the nest while the male defends the nesting site from intruders.
Eastern bluebirds tend to lay an egg every day until the clutch reaches 3-6 eggs. The eggs are usually pale greenish blue or occasionally white. The female will then incubate the eggs, typically when the last or second-to-last egg is laid.
The incubation lasts around two weeks, after which the young hatch and remain in the nest until they are ready to fledge. The female and male both care for and feed the young during this time.
To better support bluebirds during nesting and breeding seasons, consider providing them with nest boxes that mimic their favored nesting cavities.
Additionally, place blue-colored bird nest boxes in areas where they will be protected from predators and harsh elements. Supporting bluebirds during this crucial period can encourage a thriving population and contribute to a more diverse and lively backyard bird community.
Characteristics and Identification
Eastern Bluebirds (Sialia sialis) are small members of the thrush family (Turdidae) known for their distinctive plumage. Adult males typically have a brilliant royal blue head and back, with warm red-brown breasts.
Females display a more subdued color palette, sporting dark blue head, gray-brown upperparts and a lighter gray underside, with blue tinges in the wings and tail. Western Bluebirds show more variation; males exhibit blue heads and backs, contrasted with reddish-orange feathers on the chest.
These birds are part of the passeriformes order and generally measure 6.5 to 8.3 inches long. Eastern Bluebirds have a wingspan of around 9.8 to 12.6 inches and weigh approximately 1 to 1.2 ounces.
Sounds and Calls
Bluebirds are known for their melodious, soft, and musical calls. Eastern Bluebird songs are composed of clear, high-pitched notes that vary in pitch and tone. Their call notes include a short, soft “chirp” or “tru-ly” sound. On the other hand, Western Bluebirds have a song with shorter phrases and single notes, accompanied by quiet call notes such as “pew” or “che-check.”
Several bird species have physical and vocal attributes similar to blue pigment, often leading to confusion in identification. Although larger, the American Robin (Turdus migratorius) shares similar combinatorial color patterns with bluebirds, presenting a gray upper body, white throat, and red breast. The Blue Jay (Cyanocitta cristata), belonging to the Corvidae family, is also blue but can be differentiated by its characteristic blue crest, white facial markings, and black necklace.
It’s essential to consider plumage, physical measurements and sounds when identifying bluebirds and differentiating them from similar species. A photo gallery or field guide can be invaluable tools for further reference and comparison to confirm ID info.
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Feeding and Foraging
Bluebirds primarily feed on insects, with spiders, caterpillars, and grasshoppers being some of their favorites. They can be found foraging in fields, meadows, and other open areas with low-growing grasses. They often catch their prey by swooping down from a perch or while flying in mid-air.
Mealworms are particularly popular with bluebirds and can be provided all year round. Feeding bluebirds mealworms can help supplement their natural diet, especially during colder months when insects are scarce. Live mealworms are preferred, but dried ones can also be used.
In addition to insects, bluebirds enjoy a variety of fruits and berries as part of their diet. Some of their favorite sources include sumac, holly, dogwood, pokeweed, hackberries, grapes, and cherries. Offering these berries in your backyard can help attract bluebirds and boost their nutrition.
Bluebirds also eat softened fruits, such as raisins and grapes, which can be offered at feeders. To make these fruits more appealing sky blue, and easy to eat in blue light, soak them in water for a few minutes before placing them in the feeder.
When it comes to foraging, bluebirds typically search for food close to the ground or in shrubs, trees, and vines. They use their keen eyesight and agility to hunt and catch prey, often plucking insects directly from leaves, branches, or the ground.
Conservation and Threats
Eastern Bluebirds have faced challenges in their populations due to habitat loss and competition for nesting sites. In particular, populations have declined in areas such as Massachusetts. Some bluebirds are known as “partial migrants,” whose movement during the winter depends on weather and food availability. Cold winters can cause high mortality rates among these birds.
Predators and Threats
Threats to bluebirds include both predators and human-caused factors. Predators such as House Sparrows, originally from Europe, have been known to compete with bluebirds for nesting sites. Additionally, native species like the House Wren can pose serious competition for bluebirds regarding nesting boxes.
Habitat loss, degradation, and fragmentation represent significant threats to migratory birds, with development being one of the primary human-caused factors. Migratory birds require essential breeding, feeding, shelter, and survival resources, including access to food, water, and nesting sites.
To help protect and conserve bluebird populations, efforts can be made to:
- Preserve and restore natural habitats
- Install and maintain appropriate nesting boxes
- Monitor and manage invasive species
- Educate the public about the importance of bird conservation
Uniquely Blue Birds
The world of birds is vast and diverse, but bluebirds hold a special place due to their vibrant coloration and striking appearance. Some of the most iconic types of bluebirds are the Blue Jay, Eastern Bluebird, and Lazuli Bunting.
Blue Jay (Cyanocitta cristata) is one of the most recognizable birds in North America. These birds are adorned with light and dark blue feathers and coloring and feature a distinctive crest on their head. They are known for their intelligence and ability to mimic a variety of calls. Blue Jays can typically be found in woodlands, making them a year-round resident for many regions in North America.
Eastern Bluebird (Sialia sialis) is a charming bird with a length of 15-20 cm, a weight of 25-35 g, and a wingspan of 25-35 cm. Males have an all-blue top with rusty reddish-orange bellies, while females have similar coloration but appear much duller and faded. Eastern bluebirds are part of the Sialia family, including the Western Bluebird (Sialia mexicana). They are known for their sweet and melodious calls, making them a delight for bird enthusiasts.
Lazuli Bunting (Passerina amoena), a small passerine bird found in North America, also sports vibrant blue plumage, particularly in males. The male bird showcases a bright blue head, back, and wings with a white belly and a brownish-red breast. Conversely, the female is mostly brown with a subtle blue tint on the wings and tail. These birds are admired for their sweet and melodic songs.
There is still much to explore regarding these uniquely beautiful bluebirds, from their scientific classifications to their life histories. As year-round or permanent residents in various regions, they often serve as captivating subjects for nature lovers, offering glimpses into their intriguing world.
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