One of the most welcome sights for any gardener in North America is the presence of a bluebird. Bluebirds (Sialia genus) are very effective pest controllers due to their voracious appetite for insects, and thus many homeowners build specialized nest boxes to attract them.
Bluebirds are members of the thrush family, and all three species are native only to North America. The most common species is the eastern bluebird, which can be found throughout the United States and much of Canada east of the Rocky Mountains. The western bluebird is primarily found west of the Rockies in a range that stretches from Canada to Mexico. The third species, the mountain bluebird, usually lives at elevations above 5000 feet throughout the entire western half of the continent. In areas where species overlap, the mountain bluebird usually dominates the territory.
Though all species are named for their blue plumage, there are coloration differences that make the different species easy to identify. Eastern bluebirds have orange throats, whereas western bluebirds have either blue or grey throats for males and females respectively. Male mountain bluebirds are a darker shade of blue than other species and lack orange coloring anywhere on their bodies.
All species of bluebirds are usually migratory; however some remain as year-round residents in more temperate climates. Bluebirds prefer to live in semi-open country such as meadows or woodlands with clearings nearby. The need for nearby open ground is due to their hunting habits, as they prefer to hover above the ground or swoop down from perches to catch insects. Bluebirds will often supplement their diets with fruits and berries as well.
Natural bluebird nesting habitats are cavities in trees. However, by the mid-twentieth century bluebird populations had sharply declined due to competition from introduced nonnative birds such as house sparrows and common starlings. House sparrows in particular are known to invade bluebird nests frequently, with the bluebirds and their nestlings often driven away or killed. Luckily, volunteer groups have worked hard over the last 30 years to build specialized nest boxes to help the population of these beneficial native birds recover.
The average bluebird lifespan is 3-7 years in the wild.
The eastern bluebird is the state bird of Missouri and New York.
The Bluebird Box
The Cornell Lab of Ornithology
The Self-Sufficient Gardener