Blue Jay vs. Bluebird: 14 Key Differences

Blue jays and bluebirds are believed to bring hope and energy. After all, blue feathers have been a symbol of good luck for centuries. 

But identifying the blue birds in your backyard can be challenging, especially if you’re not a birdwatching expert.

The main differences between blue jays and bluebirds are the size and plumage colors. Blue jays are about the size of magpies, between nine and 12 inches long. Bluebirds are smaller, their beak-to-tail length rarely exceeding eight inches. Blue jays’ plumage combines shades of blue with white and black. Bluebirds have blue heads, wings, and backs, but reddish-brown chests.

The table below compares the main differences between bluebirds and blue jays*:

*Data in the table was sourced from scientific publications, research papers, nature magazines, and other official online sources cited throughout this article. For comparison purposes, bluebird characteristics in the table refer to Sialia sialia (eastern bluebird) species, which is the most likely to occur in the same geographic range as blue jays.

14 Differences Between Bluebirds vs. Blue Jays

1. Classification

The main difference between blue jays and bluebirds is the taxonomic family. 

Blue jays are corvids, members of the Corvidae family belonging to the genus Cyanocitta. The species, Cyanocitta cristata, is divided into four different subspecies that are very similar in size, appearance, and behavior. 

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Bluebird is an umbrella name that can designate any of the three bluebird species: Sialia sialia (eastern bluebird), Sialia currucoides (mountain bluebird), and Sialia mexicana (Western bluebird). 

Eastern and mountain bluebirds are native to North America. They are similar in size, but differences in color makes it easy to tell them apart.

Even though both species are common in their home ranges, eastern bluebirds are more abundant and more likely to spot in urban and suburban areas. 

Western bluebirds are very similar to eastern bluebirds in size, color, and plumage patterns. The different brown on the chest is often the only telltale that they belong to a different species.

2. Plumage  

Regardless of the type of bluebirds that are likely to visit your garden, telling blue jays from any bluebird species is easy as pie. 

The main characteristic of blue jays is the combination of bright blue on top with grayish blue on the chin that fades to an off-white on the belly and rump. The wings and tails are bright blue with black and white bands.

These birds also have a black collar and black markings on the sides of the head and at the base of the bill.

Eastern bluebirds, which are the most likely to occur in the same geographic ranges as blue jays, are a vivid blue on the upper sides and a rusty-brown or brick-red on the throat and breast. The belly and rump are usually white. 

Western bluebirds have a similar coloring, but their chests are more of a chestnut brown. The color extends from the chest over the shoulders, a trait that is not found in the eastern variety.

Another difference is the darker gray undersides of the western bluebirds. 

Mountain bluebirds are the easiest to tell apart from western and eastern bluebirds alike.

Their main plumage color is a sky blue, lighter than the vivid shade seen in the two other species. They also lack the reddish underparts. 

Blue Jay Male vs. Female 

Differentiating between blue jay males vs. females is near impossible, as the only sexual dimorphism is the size.

Males are typically larger than females. However, female blue jays have plumage colors and patterns identical to males.

For this reason, the best way to distinguish between them is based on their breeding and nesting behavior – males court females and females brood the eggs.

Bluebird Male vs. Female

Distinguishing between bluebird males and females is a lot easier, regardless of the actual species you’re observing. 

Eastern bluebird females are grayish above with blue-gray wings and tails. They have reddish chests, but the color is much duller than males. 

Western bluebird females are a dull gray-buff with orange chests and bluish wings and tails.

Mountain bluebird females have the dullest coloring, usually a brownish-gray overall with blue tinges on the tips of the wings and tail. The belly color is a light grey.

3. Size

While the color combination and patterns can help you distinguish between blue jays and bluebirds easily, another relevant difference between the two species is the size. 

Blue jays are about the size of a small magpie, measuring around nine to 12 inches from bill to tail. 

Bluebirds (all three species) are about the size of a house sparrow or downy woodpecker, measuring between six and eight inches in length. 

4. Weight

Weight is closely related to size, so it doesn’t come as a surprise that blue jays are heavier than bluebirds – around three times heavier.

In detail, they typically weigh between 2.5 and 3.5 ounces. Bluebirds can weigh around 1.09 ounces, but they are often lighter. Their average weight is just under an ounce.  

5. Wingspan

Another difference related to size is the wingspan. 

Blue jays have a wingspan between 13 and 17 inches. Bluebirds have shorter wings and wingspans of only nine to 12 inches.

6. Bill 

Bluebirds and blue jays have similar, generalist beaks that are large yet not specifically adapted to any type of food.

These beaks allow individuals of both species to eat a variety of foods, which is welcomed considering that both species are omnivorous. 

Blue jays have slender bills that are short compared to other corvids but perfectly adapted for breaking seeds. 

Bluebirds also have short bills that are thin and pointed, perfect for picking up insects from bark creaks and crevices in branches and tree trunks. 

7. Call

Knowing the calls of a bluebird vs. blue jay can help you identify the species in your yard based on nothing but vocalizations and a glimpse of blue. 

Both species are vocal and have many calls. 

In blue jays, the most common is a “jay-jay” tweet for which the species is named. The call serves as an alarm but also as an invitation for other jays to join the flock. Other blue jay calls include rattling sounds, loud jeers, whistles, and gurgling sounds.

Eastern bluebirds produce a low-pitched warbling call that typically consists of three notes and interspersed whistles. 

During the breeding season, males and females also use a soft tu-a-wee call to keep in touch with each other.

8. Diet

Blue jays and bluebirds alike are omnivorous species, but blue jays tend to display a more carnivorous behavior.

They mostly feed on insects, but are also known for eating other small birds (especially nestlings) and other birds’ eggs. Like most corvids, they feed on carrion and small vertebrates too, including amphibians and lizards. 

In wild habitats, blue jays also eat fruits, berries, nuts, and seeds from different plants.

In urban and suburban areas, they can be seen foraging near garbage bins or feed on suet from bird feeders. 

Bluebirds are primarily insectivores, feeding on insects and larvae found under tree bark. These include beetles, caterpillars, and even bees. 

All bluebirds also feed on spiders, earthworms, and snails. Their diets rarely include small lizards and snails, while the winter diet consists mostly of berries. 

Like blue jays, bluebirds may take advantage of backyard feeders, especially in winter. However, these birds seem to prefer trays over other seed feeder types. 

9. Behavior

A similarity between bluebirds and blue jays is the social behavior both species display. 

These birds live in flocks that can range in size from a mated pair to over a hundred individuals. 

Blue jays, like most corvids, are territorial and aggressive birds. They are noisy and often drive other birds away from their food sources.

Blue jays also tend to stash food in hidden crevices or in their nests – in winter, they often hide more food than they can eat.

While blue jays are considered permanent residents in their geographic ranges, the flocks further north often migrate in winter to warmer areas. However, we only talk about partial, short-distance migrations. 

Bluebirds are also very social and flocks often count over 100 individuals. 

They are territorial and aggressive against intruders when it comes to defending their nesting or feeding territories. However, bluebirds are not as aggressive as blue jays.

Similar to blue jays, eastern bluebirds display a partially migratory behavior in the cold season, when food becomes scarce in their native territory.

10. Breeding

Blue jays and bluebirds alike are monogamous species. However, bluebirds generally don’t mate for life, and polygamy has also been observed in the species.

By comparison, blue jays rarely switch partners. 

The mated pair typically forms strong, long-lasting bonds that only break when one partner dies. Even then, the remaining partner may not mate again. 

Blue jays typically produce one brood per year. The female lays between three to six eggs per season, from March to July depending on the geographic range.

Then, they incubate their eggs for 17 to 18 days. During this time, the male provides food and sometimes shares incubation responsibilities. 

Both males and females care for and feed the nestlings until they become autonomous. 

Eastern bluebirds can breed at any time from early spring all the way through summer. They usually produce two broodings per year, the female laying between three to seven eggs per season. 

In bluebirds, females are typically the ones that build the nests and incubate the eggs. However, parental responsibility is shared after hatching.

The mated pair usually remains bonded for the entire breeding season, but they may change partners in the next season.

11. Geographic Range 

Blue jays and bluebirds occur across North America. 

The actual geographic range of bluebirds differs from species to species. Eastern bluebirds are typically found from Canada across the eastern states of the United States and all the way to Mexico. Blue jays share the same geographic range.

Western bluebirds occur in the western side of the United States, their range stretching from the Rocky Mountains border between Canada and the USA all the way to Central America. 

Mountain bluebirds have a very wide geographic range that stretches from the Nearctic regions of North America (Alaska and far north Canada) to Central America. Across the US, their range overlaps with that of western bluebirds.

12. Habitat

While bluebirds and blue jays can be found in the same geographic ranges, they have slightly different habitat preferences. 

In wild areas, blue jays are commonly spotted in mixed woodlands. Eastern bluebirds prefer open lands with scattered trees for perching and nesting. 

Both species can be found in urban parks and suburban areas, usually sitting on fences or utility wires.

13. Lifespan

Bluebirds may be smaller and weaker than blue jays, but they have a longer lifespan. 

According to experts, they can live up six to 10 years. Apparently, the oldest known bluebird in the wild lived 10 years and five months. 

Blue jays have a shorter lifespan, of about five to seven years. 

However, it should be noted that they can likely live more than bluebirds in ideal conditions. In fact, the oldest known blue jay lived 26 years and 11 months. 

14. Conservation Status

Blue jays and bluebirds alike are common in their native ranges, and they are not threatened. All bluebird species have a stable or increasing population trend.

Sadly, this is not true for blue jays. While they are still common and marked as least concerned by the IUCN, their population is in decline.

Blue Jay vs. Bluebird: Which Is More Common?

Bluebirds and blue jays can be easily spotted in city parks and backyards. However, bluebirds are much more common.

According to specialists, the number of blue jays has declined by 27% between 1966 and 2019, and there are an estimated 17 million mature blue jays left in the wild. 

Meanwhile, there are around 23 million eastern bluebirds out there. 

In addition to these, the estimated numbers for western and mountain bluebirds are 7.1 million and 6 million, respectively. For all bluebird species, the population trend is increasing, putting them at a clear advantage compared to blue jays.

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