Eastern Bluebird vs Western Bluebird: Key Differences Explained

Trying to figure out how to identify Eastern and Western Bluebirds?

If you’re short on time, here’s a summary of the differences between the Eastern Bluebird vs Western Bluebird:

  • Eastern Bluebirds are found in the eastern half of North America, while Western Bluebirds are found in the western half.
  • The Eastern Bluebird’s back is a more vibrant shade of blue than the Western Bluebird’s.
  • The rusty-red color on the breast of these birds fades to a lighter color on the Eastern Bluebird’s lower belly, vs. fading to a more grayish-white on the Western Bluebird. 
  • Eastern Bluebirds have a blue-gray head with a reddish-brown patch on their throat, while Western Bluebirds have a blue-gray head with a blue throat.
  • Eastern bluebirds prefer open fields and meadows to the Western Bluebird’s semi-open woodlands and forest edges.
  • Size-wise, the Eastern Bluebird is generally larger with longer wings and tail.

Eastern Bluebird vs Western Bluebird: Species Overview

eastern bluebird vs western bluebird infographic

Eastern Bluebird (Sialia Sialis)

The Eastern Bluebird, scientifically known as Sialia Sialis, is a small, vibrant bird that can often be spotted throughout the eastern United States, Mexico, and parts of Canada.

With its bright azure plumage and contrasting rusty-red chest, the male Eastern Bluebird is a striking sight.

Females, on the other hand, display more subdued colors, with mostly gray-blue feathers and a paler reddish chest.

When it comes to size, Eastern Bluebirds typically have a wingspan of 9.8-12.6 inches (25-32 cm) and weigh between 1.0-1.1 ounces (28-32 grams).

Identifying Eastern Bluebirds is easier by paying attention to their distinctive markings and color patterns. The male’s bright blue back, white belly, and reddish chest are key features, while the female has a more muted appearance.

Read Next: Bluebird Male vs Female

Western Bluebird (Sialia Mexicana)

Sialia Mexicana, or the Western Bluebird, is a close relative of the Eastern Bluebird but can be distinguished by its slightly different coloration and distribution.

Primarily found in the western United States, Mexico, and southwestern Canada, this species prefers open woodlands and edges of forests while Eastern Bluebirds are typically found in more open habitats.

In terms of size, Western Bluebirds are slightly smaller than their eastern counterparts, with a wingspan of 11.4-14.2 inches (29-36 cm) and a weight of 0.8-1.1 ounces (23-30 grams).

To identify them, notice that the male’s blue color extends over its throat, and its chest and shoulder areas showcase a reddish-orange hue.

The female displays overall duller colors compared to the male, but still with a touch of blue on the wings and tail.

Physical Characteristics

eastern bluebird vs western bluebird comparison

Plumage and Coloration

Eastern and Western bluebirds share some similarities in their plumage, but there are noticeable differences as well.

  • Eastern bluebirds have a royal blue back and head with a reddish-brown chest and throat, and a white belly1.
  • However, Western bluebirds have a blue throat2 and their reddish-brown chest color extends to cover their shoulders, while the royal blue color of their back covers their throat1.

Size and Shape

  • Both Eastern and Western bluebirds have a stocky shape with fairly long tails3.
  • They are similar in size, so it is important to focus more on their color patterns to differentiate the two species.
  • Eastern bluebirds are typically between 6.5 and 7.5 inches in length, while Western bluebirds range from 6 to 7 inches in length4.

Sexual Dimorphism

There is a significant difference in appearance between male and female bluebirds, making it easy to distinguish between the sexes.

  • Males: Male bluebirds have more vibrant and contrasting colors compared to females5. Adult male Eastern bluebirds have a bright blue back and head, a vibrant reddish-brown throat and chest, and a white belly1. Adult male Western bluebirds also have a blue back and head, but possess a blue throat, an orange breast, and blue-gray flanks2.
  • Females: Meanwhile, female bluebirds of both species have more subdued colors, with gray-blue plumage and paler orange or reddish coloration on the breast6. Female Western bluebirds have a blue-gray chin and neck, while female Eastern bluebirds have an orange or cream chin and neck4.
  • Juveniles: Juvenile bluebirds from both species are also similar in appearance, with gray-blue plumage and some orange or reddish coloration on the breast. As they mature, their adult plumage begins to develop, helping to differentiate between Eastern and Western species7.

Geographical Distribution and Habitat

male eastern bluebird perched on a branch
Eastern Bluebird

Eastern Bluebirds Range

Eastern bluebirds have a wide range throughout eastern North America, extending southward from central Mexico up to the southeastern parts of Canada.

Their distribution also spans all the way from Texas to the east coast, including states like New York and Florida1.

Western Bluebirds Range

The western bluebirds’ territory is primarily located in western parts of North America, specifically, from British Columbia through the western United States, such as Oregon, California, and Arizona2.

Unlike their eastern counterparts, these birds typically do not extend their range east of Texas.

Mountain Bluebirds Range

Mountain bluebirds can be found mostly in the northwestern regions of North America, with their range extending to parts of Alaska, British Columbia, and northwest territories of Canada3.

In the United States, these birds are most commonly seen in states like Colorado, Utah, Montana, Wyoming, and parts of the Rocky Mountains.

Habitat Preferences

Eastern, western, and mountain bluebirds have distinct habitat preferences according to their geographical distribution and adapting characteristics.

  • Eastern bluebirds prefer open woodlands, grasslands, and areas near human-made structures such as nest boxes4. They can often be seen perching on telephone wires and foraging in grassy areas for insects.
  • Western bluebirds inhabit woodland edges, open conifer forests, and chaparral. They are known to enjoy oak woodlands and can occasionally be found in urban parks and gardens in their range5.
  • Mountain bluebirds thrive in higher elevations6, such as meadows and open forests, mostly staying at elevations around 5,000 to 12,000 feet. Their preferred habitats include sagebrush flats, pinyon-juniper forests, and the edge habitats of Rocky Mountain conifer forests.

Behavior and Social Structure

three western bluebird huddled together on a snowy tree branch

Feeding Habits

Eastern and Western bluebirds share some similarities in their feeding habits, both primarily foraging for insects. They are known for their unique hovering behavior when searching for their prey.

Their diet heavily consists of various insects such as beetles, grasshoppers, and caterpillars.

However, they also consume fruits and berries during colder months, which they find in scattered trees within their habitats.

Courtship and Mating

Courtship between Eastern and Western bluebirds is an intricate process.

Males attract females by performing displays, such as flights, wing flapping, and singing.

Once a female shows interest, the male may flutter its wings and present her with nesting materials, further solidifying their bond.

They typically mate around scattered trees where they could build their nests in tree cavities or nest boxes.

Calls and Songs

The calls and songs of Eastern and Western bluebirds are distinct aspects of their behavior.

Eastern bluebirds have a short, wavering voice that they use when perched atop nest boxes or upon wires. These songs are an integral part of their mating process and communication.

Western bluebirds have a “pew-pew” song, which is softer than their Eastern counterpart’s.

Both species use their distinct sounds to communicate with one another, establish territory, and attract mates.

Nesting and Breeding

Nest Characteristics

Eastern and Western Bluebirds, both belonging to the Sialia genus, share some similarities in their nesting habits.

These bird species typically build their nests in cavities, such as tree holes and nest boxes.

Eastern Bluebirds are known to nest on oak limbs, whereas Western Bluebirds may be found inhabiting longleaf pine forests in areas like Alabama (source).

Occasionally, bluebirds have been reported nesting in unusual locations, like gutters which give a sense of enclosure (source).

Reproduction Cycle

The reproduction cycle for both Eastern and Western Bluebirds begins with the mating season, where males attract females with various courtship displays.

Once a pair is formed, they will search for a suitable nesting site together.

The female typically constructs the nest, lining it with grasses, pine needles, and other soft materials.

Bluebirds can lay multiple clutches of eggs per year, with each clutch consisting of 4-6 eggs (source).

On average, the incubation period for Eastern and Western Bluebirds is around 11-19 days, and the young fledge after 17-21 days from hatching.

Parental Care

Parental care for both species of bluebirds involves both the male and female sharing responsibilities.

The female incubates the eggs, while the male protects the nest and provides food for the female during this period.

After the eggs hatch, both parents continue to feed the chicks and remove fecal sacs from the nest to keep it clean.

Even after the young birds fledge, the parents continue to care for them until they become self-sufficient and learn to find food on their own.

Migration Patterns

Eastern Bluebird Migration

Eastern bluebirds follow a migration pattern that typically involves moving southward during winter months to seek out milder temperatures.

Their range extends up into some northern states and parts of Canada during spring migration, but when winter arrives, they retreat to central and southern states, reducing their distribution1.

This is especially true for bluebirds breeding in the northernmost areas of their range, as they are considered obligate migrants2.

Western Bluebird Migration

Similar to their eastern counterparts, western bluebirds also exhibit migration behavior.

Observations indicate that there is a median shift of longitude during spring migration for both eastern and western bluebird species3.

Over the past decade, eastern bluebirds have shifted slightly westward by 0.22 degrees of longitude per year, while western bluebirds have shifted eastward by 0.26 degrees of longitude per year4.

Factors Influencing Migration

Various factors influence the migration patterns of eastern and western bluebirds, such as climate and availability of food.

Both species are highly reliant on insects and fruits as food sources, and as temperatures drop, the abundance of these food sources inevitably decreases5.

Consequently, the bluebirds migrate to warmer habitats where they can find ample food supply for survival.

In addition to food availability, alterations in climate and temperature also play a significant role in the migration patterns of these North American birds6.

As global temperatures continue to rise, bluebird species are subtly modifying their distribution range, and these changes are impacting their migration behavior.

Bluebirds in Human Habitats

bluebird flying out of a bird nesting box

Bluebirds have been successful in adapting to urban and suburban environments.

The Eastern and Western Bluebirds share some similarities but have different geographical ranges and distinct physical characteristics.

Urban and Suburban Adaptations

Bluebirds have found ways to thrive in suburban areas by making use of available resources.

While they are small thrushes with straight bills, they can compete with larger birds like American Robins for food sources. Their diet mainly consists of insects, including spiders, and small fruit.

In urban areas, bluebirds readily use nesting boxes or birdhouses to build their nests.

Providing nesting boxes has become a popular way for homeowners to attract bluebirds and help them find a safe place to raise their young.

Conservation and Threats

Despite their ability to adapt to human habitats, bluebirds still face conservation challenges. Habitat loss, pesticides, and competition from invasive species have all contributed to a decline in bluebird populations. Conservation efforts, such as installing nest boxes and promoting the use of bird-friendly plants in landscaping, have proven effective in helping bluebird populations recover.

Bluebirds and Humans

Human actions can positively impact bluebird populations.

By placing birdhouses in ideal locations, monitoring them for invasive species, and maintaining diverse plant life, humans can create a supportive environment for both Eastern and Western Bluebirds.

Additionally, being responsible with pesticide use and supporting conservation initiatives help maintain the delicate balance between bluebirds and their human neighbors.

Frequently Asked Questions

What are the main differences between eastern and western bluebirds?

Eastern bluebirds have a royal blue back and head, a reddish-brown chest and throat, and a white belly.

They can be found in the eastern United States.

On the other hand, western bluebirds have a blue chin and neck, and their reddish-brown chest extends to cover their shoulders. They reside in the western US.

How do their habitats vary between eastern and western bluebirds?

Eastern bluebirds inhabit open woodlands, farmlands, and orchards, while western bluebirds prefer more mountainous and coniferous regions.

Western bluebirds are often found in open areas like meadows and near forests.

What are the distinct physical features of male and female bluebirds?

Male eastern bluebirds are more brightly colored than females, with a vibrant royal blue head, back, and wings, a reddish-orange chest, and a white belly.

Female eastern bluebirds have a duller, grayish-brown tone with a subdued hue of blue on their wings and tail.

Western bluebird males have a bright blue head, back, and wings, with a reddish-brown chest and throat, whereas females display a more muted gray-brown color with paler blue wings.

How do their nesting behaviors differ between eastern and western bluebirds?

Eastern bluebirds build their nests in tree cavities or nest boxes and use various materials like grass, feathers, and pine needles. They usually have two broods per breeding season.

Western bluebirds also nest in cavities, but they more commonly use oak or pine trees and prefer nest boxes with entrance holes facing either south or east. They might have one or two broods per breeding season.

What are their respective migration patterns?

Eastern bluebirds may partially migrate, depending on the availability of food sources and weather conditions. Northern populations tend to move south during winter, while southern populations are more sedentary.

Western bluebirds can also migrate depending on resources and altitude, with many moving to lower elevations or more southerly locations for the winter months.

How can I attract both eastern and western bluebirds to my backyard?

To attract bluebirds to your backyard, provide a suitable habitat with native plants and ample food sources.

Offer fresh water in bird baths, put up nest boxes or birdhouses designed for bluebirds, and grow native fruit or berry-producing plants.

Additionally, you might consider providing mealworms in a feeder specifically designed for bluebirds to supplement their diet.

Keep pets and other predators away from nesting and feeding areas to ensure a safe environment for them.


  1. https://bluebirdlandlord.com/eastern-western-and-mountain-bluebirds-species-comparison/ 2 3 4 5
  2. https://www.birdsandblooms.com/birding/bird-species/songbirds/bluebird-seeing/ 2 3 4
  3. https://www.allaboutbirds.org/guide/Western_Bluebird/species-compare/ 2 3
  4. https://a-z-animals.com/blog/western-bluebird-vs-eastern-bluebird-what-are-the-differences/ 2 3 4
  5. https://bluebirdlandlord.com/western-bluebirds-vs-lazuli-buntings/ 2 3
  6. https://www.allaboutbirds.org/guide/Eastern_Bluebird/overview/ 2 3
  7. https://www.allaboutbirds.org/guide/Western_Bluebird/overview/

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