Types of Bluebirds Guide (Sialia)

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Reina loves watching birds and learning new ways to identify them. When she started her own lawncare company, she fell in love with our feathered friends. Currently, she is learning how to identify them from their song! She loves to share her tips, tricks, and product recommendations here on Birding Insider; you can get the most out of your birding hobby!

Taxonomy

Bluebirds belong to the genus Sialia. William John Swainson created this genus in 1827. Swainson was an English naturalist and artist studying ornithology, malacology, conchology, and entomology. The genus welcomed the Eastern Bluebird first of the three species.

Eastern and Western Bluebirds each have several recognized subspecies which are hard to differentiate. You’ll need to take location, size, and coloration into consideration.

Eastern Bluebird (Sialia sialis)

Subspecies:

Sialia sialis sialis: North America, southern Canada to northeastern Mexico.
Sialia sialis bermudensis: Bermuda.
Sialia sialis fulva: Southwest U. S. to Central Mexico.
Sialia sialis nidificans: East-Central Mexico.
Sialia sialis guatemalae: Southeast Mexico and Guatemala.
Sialia sialis meridionalis: El Salvador, Honduras and Northern Nicaragua.
Sialia sialis caribaea: East Honduras and Northeast Nicaragua.

Western Bluebird (Sialia mexicana)

Subspecies:

S. m. occidentalis: Southwest Canada to northern Baja California
S. m. bairdi: the Western U.S. to northwest Mexico
S. m. jacoti: Central Southern U.S. and northeast Mexico
S. m. amabilis: North-central Mexico
S. m. nelsoni: Central Mexico
S. m. mexicana: South central Mexico

Mountain Bluebird (Sialia currucoides)

No subspecies

Identification & Range of Eastern, Western, and Mountain Bluebirds

While bluebirds deliver their primary identification feature in their name, there are a few differences across species, and you may often wonder which bluebird you’re looking at. There are differences between the coloration of males and females, so be sure to focus and take notes while observing these beauties for later identification support.

Eastern Bluebird Identification

Depending on where you live, the Eastern Bluebird is the most likely bluebird to flutter across your line of sight. This usually means that it is the first bluebird folks learn to identify, thus confusing it with all the others.

Size & Shape

Eastern Bluebirds have plump bodies, round heads, and large black eyes. Their wings look exceptionally long, alongside short legs and a stubby tail. Their beaks are short and straight. They are 7.3 inches in length with a wingspan of 11.2 inches.

Color Pattern

Male Eastern Bluebirds have deep blue feathers atop their round heads, back, and wings. They have rusty orange throats, necks, breasts, and flanks that meet a white underbelly and bum.

Female Eastern Bluebirds have gray heads and backs, with warmer orange-brown throats, necks, and breasts. Their wings and tail are primarily gray, with highlights of blue scattered throughout. Their bellies are a buffy beige color.

Identification Tip: The blue feathers on a male Eastern Bluebird’s face stop at their beaks. They have orange throats and necks.

Eastern Bluebird Range & Habitat

The Eastern Bluebird has the most extensive range of all the bluebirds. These birds are year-round residents of their range, with migration sometimes occurring in the northernmost portion of their distribution. Their North American distribution begins in southern Canada, extends throughout the eastern half of the United States until reaching the border of the rocky mountains, and continues south to central Mexico and Honduras.

Eastern Bluebirds live in open areas like meadows, fields, farmland, and orchards. They can also be found in woodlands and along the forest edge. Their distribution throughout the western portion of their range is due to the suppression of wildfires and increased tree planting.

Western Bluebird Identification

Western Bluebirds have a very similar appearance to Eastern Bluebirds, but there are a few key differences that nature has been kind enough to emphasize.

Size & Shape

Western Bluebirds have smaller bodies than Eastern Bluebirds, but their shapes are similar. Plump bodies, long wings, short legs and tails, and short straight bills. They have large heads with round black eyes. They are about 6.9 inches long, with a wingspan of 12.4 inches.

Color Pattern

Male Western Bluebirds have blue feathers covering their heads, necks, and throats. Blue extends below the beak until the chest, where it is met with a rusty orange breast and flanks. Their bellies are light blue or buffy gray white, depending on their age. Their backs are chestnut-brown, and their wings are blue with orange above and below.

Female Western Bluebirds are a warmer gray than their Eastern counterpart. This includes their head, back, and wings. They have a rich red-brown breast and a grayish belly. Blue highlights are mixed in their wings and tail feathers.

Identification Tip: The head of a male Western Bluebird is entirely blue. Blue feathers extend to their breast and end in a clean line where it meets their orange-brown chest.

Western Bluebird Range & Habitat

Western Bluebirds are the least widespread of the bluebird species. Their range includes the northeastern corner of Montana and continues to the southwest corner of Texas. They migrate and breed from eastern British Columbia to central Mexico.

The Western Bluebird differs from the Eastern Bluebird in their preference of habitat. Western Bluebirds are less likely to be found in open meadows and prairies. Instead, they are commonly found in open woodlands. Deciduous and evergreen forests of ponderosa pine, pinyon, conifers, and aspens are their top choice. Logged forests with dead trees and snags and areas that have been burned are perfect for this species due to the increased availability of nesting sites and perching spots. They can be found wintering in the desert, oak forests, or streamside woods.

Mountain Bluebird Identification

The Mountain Bluebird is the simplest to identify due to its distinctly different coloration from the Eastern and Western Bluebirds.

Size & Shape

Mountain Bluebirds are small thrushes that fall between the size of a sparrow and a robin. These birds are typically 7.1 inches in length and have a wingspan of 12.6 inches. They have round heads, large black eyes, plump bodies, long wings, and long tails.

Color Pattern

Male Mountain Bluebirds are lovely powder blue throughout their heads, backs, wings, and tails. The blue color becomes deeper along the edges of their wings and tail feathers. Chins and necks lighten to a sky blue that extends to the breast. Their underbellies and rumps are white. They have thin and straight black bills.

Female Mountain Bluebirds have light gray-brown bodies with blue accents along the wings and tailfeathers. Their underbellies are a buffy white. They have a thin white ring around each eye. Their throats and breasts are dusty gray or pale orange-brown.

Identification Tip: Mountain Bluebirds have longer tails than other bluebird species. They do not usually have any orange color. Females are a lighter gray than other female bluebird species.

Mountain Bluebird Range & Habitat

Mountain Bluebirds have the most extensive range, second to the Eastern Bluebird. Their range extends from Alaska through Canada to central Mexico. In the United States, they occur as far west as California and as far east as northwestern Montana to western Texas.

Mountain Bluebirds migrate south in the winter and north towards Canada and Alaska during the summer. They can be found at elevations up to 12,500 feet and prefer prairies, meadows, and alpine hillsides. They avoid desert environments and seek out lower elevations come winter.

Bluebird Areas of Overlap

Are you wondering which regions you’re most likely to confuse bluebird species? Until you become very comfortable identifying each of these species of bluebirds, you’ll want to keep reading to ensure you know exactly which bird you’re looking at!

Eastern & Western Bluebird Range Overlap

Eastern and Western Bluebirds are the most similar in appearance, but luckily only overlap in a few limited areas. From October to February, these two species overlap in central Arizona, western Texas under the panhandle, and Central Mexico.

Mountain & Western Bluebird Range Overlap

The Mountain Bluebird has a more extensive range than the Western Bluebird. However, their area of overlap is considerable. This doesn’t typically prove to be much of a challenge for even the most novice birdwatcher due to the drastic difference in coloration between the two species.

Nonetheless, it’s helpful to note that the Mountain Bluebird is the only bluebird to occur in Montana, Saskatchewan, British Columbia, Alberta, and Alaska.

In areas of overlap, the Western Bluebird is the first to establish its territory and often fights during the nest-building process.

Eastern and Mountain Bluebird Range Overlap

Eastern and Mountain Bluebirds have the most significant overlap of all the bluebird species. These overlap areas occur from October through February and include northwest Texas, eastern Arizona, eastern Utah, and western Colorado.

Similar to the overlap between the Mountain and Western Bluebird, these two species have distinctly different colorations, so it’s relatively simple to tell them apart.

Bluebird Diet and Feeding

All three bluebird species have omnivorous diets and are perch foragers. While sitting atop a perch, they hunt for food on the ground. Once spotted, they hop to the ground or make their catch mid-air.

Mountain Bluebirds are the only of the three species to utilize hovering as a hunting foraging method. This is due to their greater wing area and often lower body weight. Hover foraging requires more energy and is only used when the food supply is scarce.

Commonly eaten insects include grasshoppers, crickets, beetles, caterpillars, and spiders. A bluebird’s diet is supplemented with fruits like grapes, black cherries, and blueberries. In the winter, berries from shrubs like mistletoe, juniper, and elderberry are essential.

Bluebird Breeding

Bluebirds are socially monogamous birds. This means that a male and female choose to be together during the breeding season and identify a specific territory where they will nest and raise young. In some cases, when a mate dies, a new partner will be selected.

Bluebirds are cavity nesters. Since they do not have bills suitable for excavating, they rely heavily on woodpeckers and naturally occurring cavities like those formed from broken branches. Artificial holes provided by homeowners, bird lovers, and conservationists are helpful, and bluebirds do not show a preference between artificial and natural nesting cavities.

Male bluebirds seek a suitable nesting location and hang out near it, sometimes collecting a pile of nesting materials to display nearby. Females make the rounds until they see their ideal real estate. Sometimes, she will select a mate but change the nesting site.

Once a nesting cavity is deemed worthy, the male and female enter the cavity together to signify their bond. Males will protect their female mate from other males who may attempt to copulate, ensuring they do not raise another bird’s young.

Bluebird Nesting & Eggs

Females take on the sole responsibility of building a nest suitable for raising the pairs brood. This process takes her anywhere from 5-14 days. Long grasses, pine needles, twigs, animal hair, and feathers are collected to make a loose cup. Since she is building it inside a cavity, it does not need to be as tightly woven as other birds’ nests.

One week after nest completion, the female will begin the task of laying eggs. She will usually lay three to seven eggs, with five being common. Eggs are laid one day apart from each other. Incubation begins on the day the last egg is laid, and the duration depends on the weather of the region the bluebird is nesting in. The average incubation period is 13 days.

The eggs of bluebirds are a beautiful light blue color due to a bile pigment called biliverdin. We all have this pigment, which is also responsible for the blue eggs of other birds, such as robins. In humans, this pigment is responsible for those ugly blue-green bruises we all get from time to time.

As the incubation period ends and the eggs begin to hatch, the female and male remove eggshells from the nest or will sometimes eat the shells. Young are born anywhere from a half hour to a full day apart from each other. The male and female both take on feeding and cleaning responsibilities. A clean nest means fewer predators! Bugs are captured around the clock, and fecal sacs are removed from the nest as they are produced.

After 21 days, the chicks fledge. They remain nearby and will call for assistance from their parents as they learn to become more self-sufficient.

Bluebird Population

Eastern Bluebirds have a population of 23 million breeding individuals. This species ranks a 7 out of 20 on the Continental Concern Score. Although the species is classified as “least concern” by the IUCN, the species experienced declining numbers in years past. It is thanks to the efforts of conservationists and bluebird landlords (folks who put out nesting boxes) that we began to see rising population numbers for the Eastern Bluebird.

Western Bluebirds have a population of 7.1 million breeding individuals. They are rated 9 out of 20 on the Continental Concern Score. While this species is not endangered, its habitat is threatened. Increases in the logging industry and forest fires have reduced the number of suitable nesting sites for Western Bluebirds. Conservationists focus on providing artificial nesting sites and boxes throughout their range to increase their numbers. The Western Bluebird is protected under the U.S. Migratory Bird Treaty.

Mountain Bluebirds have the smallest population of the three species, with only 5.6 million breeding individuals. Although they have experienced a decline in their population over time, they are currently a species of least concern, ranking 11 out of 20 on the Continental Concern Score.

The introduction of invasive bird species such as House Sparrow and European Starling into North America in the 19th century has led to fierce competition for nesting cavities. Woodpeckers, wrens, swallows, and flycatchers compete with bluebirds for available cavities.

Bluebird Predators

Birds are susceptible to many different kinds of predators. Unfortunately for the bluebird, there is a laundry list of bad guys who like to interfere with both adult bluebirds and their young.

Cats

I’m sorry to tell you this, but Whiskers is a murderer. It’s not his fault, just his instinct. It may not surprise you, but cats significantly threaten birds and kill about 2 billion birds yearly. When you put a nesting box in your yard, consider keeping your house cat indoors during the breeding season. When a cat kills an adult, this likely means the entire nest will fail.

Another way to help support bluebirds in your area is to trap (and neuter) feral cats. Once a cat has been trapped and taken to the proper adoption facility in your area, it has a chance of finding a furever home. So it’s really a win-win.

House Sparrows and European Starlings

House Sparrows and European Starlings are the cause of nesting competition for bluebirds. Both the sparrow and starlings are non-native invasive species introduced in the late 19th century by a group of literary lovers who wanted the U.S. to have every bird ever mentioned by Shakespeare. Little did they know that this was a truly awful decision and one of the reasons why TSA and customs forbid you from bringing non-native items home from your travels abroad. I’ve had to tearfully toss (ok, I didn’t cry, but it was sad) many seashells aside as a TSA agent hovered over me.

Sparrows and starlings will aggressively evict bluebirds from their nesting cavities. They have been observed luring adult bluebirds away from their nest with clever and deceitful threatening behavior. They will attack young and sabotage eggs to get what they want, and even the most vigilant bluebird can fall prey to their aggressive attempts.

Larger cavity-nesting birds, like woodpeckers, can also drive bluebirds out of valuable nesting cavities by force or sabotage. Hawks, falcons, and owls are known to feed on juveniles. It’s a bird-eat-bird world out there.

Other Common Predators

Sadly, there are many other predators that cause problems for bluebirds. Snakes, squirrels, chipmunks, raccoons, weasels, and mice are all known to raid the nests of bluebirds. Male bluebirds stand guard near their nest to defend it against unwanted guests.

Attracting Bluebirds to Your Yard

You can do many things to make your yard an oasis for bluebirds. The main factors to consider are habitat, food, water, and shelter. It may take time and patience for them to make the discovery, but once they catch on, you’ll likely be rewarded with bluebird visitors yearly.

To create a suitable habitat for bluebirds, you’ll need to have an open space with scattered trees and places for perching. This is their preferred environment in the wild, so it makes sense they’d want the same requirements out of your yard.

Plant bluebird-friendly shrubs and trees. Trees such as eastern red cedar, winterberry, chokeberry, crabapple, and serviceberry are beautiful and will give bluebirds plenty of berries while providing them with perches for hunting. Popular berry-producing plants that provide them with food through the winter are juniper, blueberry, elderberry, sumac, and holly.

You might think filling your birdfeeder with typical birdseed is enough to attract them, but they’re actually rather picky. Suet that has been shredded or is crumbled and blended with fruits and insects is ideal.

Additionally, bluebirds love mealworms. If you’re icked out by bugs, consider dried mealworms. You’ll need to place these in a platform feeder or bluebird-specific feeder. Live mealworms can be purchased at any pet store, but if you’re hardcore and want to save money, you can try your hand at breeding mealworms. This will give you a never-ending supply of live mealworms that will easily attract several species of birds, including our beloved bluebird.

Running water is a bluebird’s preferred choice, so unless you’re next to a creek or stream, you’ll need to provide them with fresh, clean water. A birdbath with two to three inches of water is a great start. Take it to the next level by adding a fountain. The birds will likely hear the fountain and seek out the water source. Moving water also glistens in the sunshine, which will catch their eye. If your region reaches freezing temperatures in the winter, add a water heater to the birdbath. You may not want to step outside much (especially with the hose) but supplying birds with liquid water in the winter is an honorable task, and I will be very proud of you!

To give your bluebird friends suitable shelter during the winter, hang roosting boxes throughout the yard. You will attract woodpeckers, chickadees, wrens, titmice, and nuthatches. Roosting boxes can accommodate several birds and protect them from storms and severely cold weather. If it is safe to do so, leave dead trees alone. These are valuable roosting and nesting locations.

Wooden birdhouses act as artificial nesting cavities. Studies have shown that bluebirds show no preference between a natural and artificial nesting cavity, so your chances of luring in tenants are high. Place the nesting box four to seven feet from the ground in a relatively open area with the entrance hole facing away from the wind. Avoid painting it if possible. If you recycle an old birdhouse that needs a coat of paint, opt for a neutral color. Brightly painted birdhouses, while cute, attract predators easily and pose safety risks to the inhabitants.

There are a few housekeeping rules to take note of when you decide to become a bluebird landlord. Each seasons, clean birdhouses with nine parts warm water and one part bleach. This will kill bacteria and parasites and ens nures future tenants receive a warm welcome. Do the same with roosting boxes. Provide nesting materials like pine needles, animal fur, and twigs. I like to brush my cat outside and leave the hair in the yard for the birds to collect.

FAQ

Question: What do bluebirds symbolize?

Answer: Bluebirds are commonly associated with hope and joy. The sight of a bluebird lightens your heart and reminds you of all the amazing things nature is capable of. In indigenous cultures, it is believed that bluebirds connect the living and lost loved ones.

Question: What do the bluebirds eat?

Answer: Bluebirds eat a variety of insects like crickets, beetles, grasshoppers, and cicadas. In the winter, bluebirds eat from berry producing shrubs and trees such as juniper, serviceberry, elderberry, holly, sumac, and winterberry. These plants also provide valuable perching and shelter spots.

Question: Where do most bluebirds live?

Answer: Bluebirds live in a variety of different places across North America. Which species you’re most likely to see depends on the region you’re located in. Western Bluebirds are common across the western United States from California to the Rocky Mountains. Eastern Bluebirds are plentiful from southern Canada to central Mexico. Mountain Bluebirds have a similar range to Western Bluebirds but also occur in Alaska and Canada.

Question: Are bluebirds good to have around?

Answer: Bluebirds are wonderful to have around! Their diets are composed of about 70% insects, so inviting them to stay in your yard (use the tips above) is a great idea.

Question: Do bluebirds come back to the same house every year?

Answer: Yes. Studies show that 30-40% of bluebirds return to the location where they nested the previous year. Keep your bird tenants happy by keeping roosting houses and birdhouses clean each season.

References

Do you want to learn more about bluebiers? check out our guides!