We have a pair of bluebirds busy building a nest under the eve of our house that I’m allowing because I enjoy having them around. They are pretty things with an appetite for insect pests. The first sighting of bluebirds is considered a sign of Spring.
Bluebirds (Sialia sialis) are easily identified by their sky blue back and rusty colored throat and breast (they are cousins to the robins). Females are not as brightly colored as males. The birds are most often seen sitting on an isolated perch, or hunting for insects on the ground.
Bluebirds feed mainly on insects and other invertebrates during the warm seasons, including grasshoppers, weevils, caterpillars, beetles, sow bugs, worms, and even snails. During the winter they prefer fleshy fruits from holly, dogwood, grape, sumac, elderberry, red cedar, poke, and poison ivy. The birds feed by perching on a high point and swooping down to catch bugs near the ground. If you want to attract them to your bird feeder, try putting out crushed peanuts.
Bluebirds nest in cavities found in dead trees and old wooden fence posts. The nesting period lasts from late March through August, laying one to three clutches, of three to six pale blue eggs. Incubation takes about two weeks, and then the parents feed the young for around 20 days. After that they are on their own and have a life expectancy of one year.
In the northern states bluebirds migrate south for food. They usually don’t migrate in our area except during exceptionally cold weather or when food supplies are low. The birds will group up and seek cover in heavy thickets or other areas where there is adequate food and cover.
Bluebird populations dropped dramatically in the early to mid 1900s due to introduced starlings and house sparrows, which competed for nesting cavities. The natural cavities in older trees are still in short supply, and metal posts have replaced wooden fence posts that rot to form acceptable nest cavities. Bluebirds made a comeback in the 1960s and 70s due to a campaign to encourage folks to set up bluebird nesting boxes designed specifically for them. For anyone that would like to help the birds out, plans for nesting boxes are easy to find on the internet. You can also find plans at your county Ag Extension Service.