There are two kinds of bluebirds: the eastern bluebird, found from Oklahoma and east, and the mountain bluebird, occurring west of Oklahoma.
Key Takeaways
Telling Males and Females Apart
Male eastern bluebirds have a bright blue head, back, wings, and tail. The throat and breast are brightly rufous. Females are similarly colored but more subdued, and they usually have a white eye-ring.
Nesting and Eggs
Bluebirds nest in tree cavities but will readily use bird boxes. Beginning in late March, bluebirds may be seen nesting in this area. They make a cup-shaped nest of grasses and lay 4 to 5 sky-blue eggs. Rarely, the eggs are white and are referred to as albinistic (or albino). It’s a genetic mutation that occurs in about 5% of females. The babies will be colored normally, though.
I’ve seen white eggs once and wish I had taken pictures of them. Eggs hatch in approximately 2 weeks, and the young will fledge 3 weeks later.
If you enjoy drawing birds like these to your own yard, a few well-placed boxes and a reliable food and water source go a long way. Our guide to homemade hummingbird food is a good companion read for anyone building a more bird-friendly homestead.
Watch Out for House Sparrows
House sparrows use bird boxes as well. They are more aggressive than bluebirds and will often destroy the eggs and kill the babies. Because of that, house sparrows should not be allowed to nest in bird boxes, and their nests should be pulled out. I check our boxes weekly during the nesting season.
House sparrows are not native to the U.S. They were introduced to Brooklyn, NY in 1851 to control caterpillar populations. By 1900 they had spread to the Rocky Mountains. Additional releases on the west coast enabled them to cover the entire continental U.S.
House sparrow nests are different from those of bluebirds. The top of a bluebird nest is well below the opening of the box. A house sparrow’s nest fills the box. They stuff the box with grasses, weeds, feathers, and other material. The eggs are whiteish with brown splotches.
For range maps, songs, and more on identification, the Cornell Lab of Ornithology’s All About Birds page on the eastern bluebird is an excellent reference. Bluebirds share the treeline with drummers. Here are seven woodpeckers you are likely to see. For another bird that takes to a nest box near the barn, see barn swallows. For another small bird with an outsized presence at the feeder, see chickadees. Water draws them in as reliably as a nest box — see how birdbaths work through the seasons. For the birds that drum instead of sing, see our guide to woodpeckers.
Frequently Asked Questions About the Eastern Bluebird
How can you tell a male from a female eastern bluebird?
The male has a bright blue head, back, wings, and tail with a rich rufous throat and breast. The female shows the same pattern in more subdued tones and usually has a distinct white eye-ring.
When do eastern bluebirds nest?
In much of their range they begin nesting in late March. They build a cup-shaped nest of grasses in a tree cavity or bird box and typically lay 4 to 5 sky-blue eggs, which hatch in about two weeks. The young fledge roughly three weeks after hatching.
Why are eastern bluebird eggs sometimes white?
On rare occasions a genetic mutation causes a female to lay white (albinistic) eggs instead of the usual sky blue. It occurs in about 5% of females, and the chicks that hatch from those eggs are colored normally.
How do I protect bluebirds from house sparrows?
House sparrows are aggressive, non-native competitors that will destroy bluebird eggs and kill nestlings. Check your nest boxes weekly during nesting season and remove house sparrow nests, which fill the whole box, unlike a bluebird’s lower cup-shaped nest.
Will eastern bluebirds use a bird box?
Yes. Although they naturally nest in tree cavities, eastern bluebirds readily take to properly placed bird boxes, which is one of the easiest ways to invite them to your property.
