These birds have similar nesting habits to the house sparrow
Only 30% of bluebirds make it past their first year of life. In the wild, they can live to be five years old. They do not have a very long life, but it is an interesting one. There are three species in the Sialia genus. These are the Western bluebird, Eastern bluebird, and Mountain bluebird. These birds are only found in North America. Depending on where these birds live will determine to what extent they migrate. Bluebirds will typically leave an area if it gets below 20 degrees Fahrenheit, or if food is scarce. Some bluebirds will remain in their home area year-round. Some bluebirds will partially migrate, and some will fully migrate.
Come fall and winter you have a chance of seeing these birds flock in groups up to ~20. Some flocks can be much larger than this. These birds have similar nesting habits to the house sparrow (also featured this month). They nest in protective cavities. Sometimes these are abandoned woodpecker holes. Sometimes these are natural holes in decaying trees, and other times these are “nest boxes”, which are human made solutions to promote more nesting. Although their populations are stable today, there has been population instability in the past. In the 1970’s, the bluebird populations fell drastically. This was believed to be caused by increased land development leading to habitat loss.
Mating occurs in spring and summer. The females may have as many as three broods, each consisting of four to six eggs. The females will incubate the eggs for roughly 20 days. They keep their eggs between 96 degrees Fahrenheit and 104 degrees Fahrenheit, anything outside this might lead to developmental problems.
Sometimes the females remain with their partner through the breeding season, and sometimes they swap out their partner for a new one. Here is a photo of a female Western bluebird. Notice how the coloration is duller compared to the male Western bluebird.
The females may have as many as three broods
Did you know?
- Bluebirds eat insects and berries. Their beaks are not suited for consuming seeds. Their beaks are also not suited for digging holes, thus why they have to use already existing holes for their shelter.
- A Western bluebird will measure roughly 7 inches long and weigh an ounce.
- Although these birds will not be attracted to a bird seed feeder, you can attract them by building nest boxes and offering mealworms.
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