Eastern Bluebirds

While enjoying the outdoors of Mammoth Cave, you may have noticed a bright blue bird with a rust colored breast, flying around and snagging an insect snack mid-air. These friends of ours are known as the Eastern Bluebird. They are frequent flyers of ours due to the Bluebird trail of nesting boxes we have established. Urbanization and other aggressive introduced species have left the Bluebird vulnerable. We believe that if we work together our efforts can make a difference in the conservation of our little blue friends. Periodically monitoring and maintaining these nesting boxes is wonderfully rewarding and brings us one step closer to nature.

Spot this Bird

The male Eastern Bluebird is easily identified by its bright blue head and wings. Females appear to have a much more dusty or duller overall color. Both males and females sport rust-colored breasts with a white belly. This small bird with a rounded head and plump body can often be seen sitting on a fence post or a nearby powerline here at the farm. Their preferred habitat includes open country with scattered trees, agricultural lands, and roadsides. These lands supply the Bluebirds’ diet that primarily consists of insects, berries and wild fruits. Their love of insects is great news for us and our cabin guests.

Population Threats

While these birds are not currently considered endangered, their population has experienced a decline. Their numbers were at a major deficit in the early 20th century when the European Sparrows and Starlings were introduced just as widespread farmlands were turned into urban housing. The aggressive Sparrows and Starlings turned out to be the Bluebirds’ number one competition for nesting spaces. As the farmland’s wooden fence posts were pulled up to make room for the growing human population, the competition was made even more fierce. The increasing difficulty and loss of habitat for the Bluebirds made them go from being as common as a Robin to the verge of extinction. Fortunately, increased efforts and man made nesting boxes led to the sustainability that we now see in the Eastern Bluebird population today.


Bluebirds are second cavity-nesters. This means that they rely on holes excavated by other animals, elements, or man made nesting boxes for their own nests. The male Eastern Bluebird brings in materials such as pine needles, grasses and animal hair as his contribution. The monogamous couple will stay together as the female builds the nest and then lays and incubates the pale blue eggs. Before the hatchlings leave the nest in a little over two weeks, the couple will take turns feeding them. It is also not uncommon for the young from a previous brood to help with feedings. Most couples average 2 broods per year.

Fun Facts

  • The Eastern Bluebird is very popular. They are commonly depicted in art, holiday cards, and other decorative items.
  • Bluebirds are seen as symbols of happiness and joy throughout many cultures.
  • One of the most distinguishing characteristics of this bird is its song. A male Bluebird has been known to sing up to 1000 songs in one hour for mating purposes. Common sounds of his song are things like “chur lee” and “chir wi”. When repeated many times, it can begin to sound like “truly” and “purity”.
  • The oldest known Eastern Bluebird was 10 years and 6 months of age. It was banded in New York in 1989 and then found dead in South Carolina in 1999.
  • Their favorite snacks include grasshoppers, beatles, spiders, and crickets.
  • There are seven currently recognized subspecies of Bluebirds.

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