Bluebirds are beautiful birds found throughout all of North America, so you have likely seen one. However, they are often mistaken for other birds that are blue in color.
There are only 3 species aptly named for where they are commonly found: Mountain, Eastern, and Western.
These birds have special characteristics as they work together to raise their young, defend their territories, and produce a variety of songs and calls. They can even mate within their species to produce hybrid offspring.
Let’s take a closer look at 14 interesting facts about bluebirds.
1. Bluebirds Do Not Have Blue Pigments In Their Feathers
People see blue on bluebirds because it is a reflected color as a result of the protein molecular structure of the feathers.
Each feather barb is made of cells that absorb all wavelengths of color except for blue. The blue wavelength is reflected back and is what you see.
Males of the bluebird species all have striking blue, whereas the females are duller in color with highlighted blue wing and tail feathers. Looking at the blue pattering on male bluebirds can help to identify them.
Male Mountain bluebirds are nearly all blue with sky-blue, cerulean tones.
Male Eastern and Western bluebirds appear similar, with some subtle differences. Eastern species have rust-colored throats and blue shoulders, whereas Western species have cobalt blue throats and chestnut-colored shoulders.
2. Bluebirds Are Commonly Confused With Other Blue Birds
Bluebirds are often confused as being the same as other birds with blue feathers. These include birds such as the indigo bunting, blue jay, blue grosbeak, red-breasted nuthatch, and kingfisher to name a few.
However, a look at their taxonomic information reveals that they are not the same.
3. There Are Only 3 Species Of Bluebirds
There are only 3 species of bluebirds in the genus Sialia.
They are Mountain bluebirds (Sialia currucoides), Eastern bluebirds (Sialia sialis), and Western bluebirds (Sialia mexicana).
Bluebirds are members of the Turdidae family, along with American robins and thrushes.
4. Bluebirds Are Found Only In North America
The 3 bluebird species are found only in North America, across parts of Mexico, the United States, and Canada.
Eastern bluebirds are found in the eastern United States in the summer months. In autumn as temperatures cool, they migrate to the southeastern U.S., Mexico, and mid-Atlantic areas.
They live in open habitats near trees such as in pastures, forest clearings, parks, and savannas.
Western bluebirds are found primarily in the western part of the United States. Some remain residents throughout the year, whereas others will migrate to California, Mexico, Arizona, and New Mexico in the winter.
They live in semi-open areas such as woods, groves, and farmland, but not in hot and dry regions.
Mountain bluebirds are primarily in the west as well, migrating in the winter to the southwestern areas of the U.S., Mexico, and parts of the Great Plains. This species lives in open areas, nesting in cavities in cliffs, trees, and dirt banks.
5. They Only Nest In Cavities (Which Impacts Population Growth)
Bluebirds nest in natural holes, woodpecker-formed cavities, as well as human-produced nest boxes. Female bluebirds make nests of loosely-woven grasses and pine needles, lining them with fine grasses, animal hair, and feathers.
The house sparrow, a non-native species to North America, aggressively competes with bluebirds for nesting spots. The bluebird population drastically decreased in the 1970s as a result of habitat loss due to land development and this competition.
Conservation efforts took place which included the placement of snug nesting boxes (4 inches square bottoms with 1 ¾ inches entrance holes). This resulted in much-improved population growth for the bluebirds.
6. Bluebirds Are Usually Monogamous
The male bluebird finds a nesting cavity, brings in nesting supplies, and sings and flutters to attract a female. Breeding takes place in the spring and summer, and a female bluebird will raise 2 to 3 broods of 4 to 6 eggs.
Bluebirds are typically monogamous for a breeding season. They may also breed with the same partner the following year.
However, bluebirds may choose a different partner if they raise a second or third brood during one breeding season. They may also choose a different nesting site or build a new one on top of the old one.
7. Male Bluebirds Help Take Care Of The Young
Female bluebirds incubate their eggs at a range of approximately 96 °F to 104°F, and anything above or below this can be lethal or negatively impact embryonic development.
The male brings the female food during this time. Incubation generally takes anywhere from 13 to 20 days depending on how well-fed the female is and the overall air temperature.
Once the hatchlings have emerged and can individually maintain their body temperature, the male bluebird steps in to help. He feeds and protects his young.
8. Bluebirds Do Not Eat Seeds
Bluebirds have an omnivore diet of insects and berries. They have short straight beaks, which are unlike the conical beaks of seed-eating birds such as cardinals or finches.
They cannot crack open seeds to consume the inner fleshy part. If they do consume seeds, they will pass through their digestive system undigested.
Bluebirds are attracted to mealworms but will eat parts of suet and sunflower hearts if they don’t have to remove hard shells. They also prefer softened fruits and berries.
9. They Can Spot Food Up To 100 Feet Away
These insect-loving bluebirds can spot a meal up to 100 feet away. They settle on low perches and powerlines to survey the ground for live insects. In particular, they will search for insects after the grass has been mowed and insects are more active.
Bluebirds will either swoop down to catch prey (drop-hunting), pick them off of tree leaves, or catch them in the air on the wing.
Mountain bluebirds in particular can hover and catch prey, unlike the eastern and western species.
10. Males And Females Are Both Territorial
Male bluebirds defend territory edges whereas females defend the nest.
Males will seek out nesting cavities and fight other males over the right to claim them. Once a female is attracted to the male’s nesting spot, they then guard the female to prevent her from breeding with other males.
Females defend their nests and release a short, sharp call to alert males to come back and help protect them.
11. Bluebirds Migrate In Flocks
When it is time to migrate for the winter, bluebirds travel in small flocks typically in groups of 4 to 20 birds. However, more than 100 bluebirds can flock together.
Generally speaking, bluebirds fully migrate, are partial migrators, or remain residential. They only leave if the temperatures are too low (below 20º F) or there is not an ample supply of food.
The climate of North America varies, so generally, bluebirds leave colder northern areas for warmer southern areas in the fall.
Males tend to arrive at wintering grounds before females, although that is not true in all cases. Some families choose to travel and spend the winters together.
12. They Have A High Mortality Rate
Around 70% of bluebirds die within their first year of life.
This is due to several factors such as predators (snakes, cats, other birds), consumption of poisoned insects (insecticides), genetics, access to food and clean water, and the lack of shelter.
However, if a bluebird survives the dangers of the world, they typically live up to 4 or 5 years of age. The oldest recorded age of an Eastern bluebird was 10 years and 6 months old.
13. Breeding Between Bluebird Species Produces Hybrid Offspring
Mixed breeding typically occurs between Mountain and Eastern bluebirds, which are more closely related than Western bluebirds.
Typically, hybrid bluebirds appear where their habitats overlap in southern Canada and the Great Plains in the U.S.
Interestingly, the hybrid bluebirds are usually fertile and capable of breeding with purebred Mountain or Eastern bluebirds.
14. Bluebirds Produce A Variety Of Frequent Songs And Calls
Unpaired male bluebirds sing a larger variety of songs producing as many as 20 in one minute to find a mate to breed with.
Male bluebird songs are often 1 to 3 notes of slurred, yet rapid succession of phrases in both loud and soft tones. Softer tones are used when female mates and offspring are nearby, and louder are reserved for long-distance communication.
Females do not typically sing and produce calls instead.
Calls are used by both males and females with the male’s pitch longer and lower. Calls are used for communication for foraging, alert or stress, to find family members, coordinate behavior, and between parents and offspring.
This video offers a quick lesson about many of the fun facts found in this article:
The sight and sounds of a breathtaking beautiful bluebird are something to enjoy.
They produce a large variety and frequency of calls and songs. Most interestingly, they do not produce blue pigments in their feathers, and the blue is a result of non-absorbed blue wavelengths.
These cavity nesters unfortunately do not have a long life expectancy rate due to the lack of shelter, predators, use of insecticides, and poor access to food supplies.
People can help bluebirds live longer lives by providing nest boxes and an ample source of tasty mealworms.