The signs of spring are starting to appear. While the plump-breasted worm-eating robins are thought of by many folks as the harbinger of spring, often in my neck of the woods, the arrival of the eastern bluebirds to the yard and nearby trees is the first avian signal that spring is on the way.
Over the last week, as daytime temperatures have reached above freezing, several bluebirds were perched in the nearby maple tree and checking out the numerous bluebird boxes scattered along the field edges. As bluebirds begin to leave their winter hangouts and appear more often outside the kitchen window or perched near the garden, we wonder what we can do to keep them around so we can enjoy watching them throughout the rest of the year.
The Eastern Bluebird, which inhabits our area, is a member of the Thrush family, Turdidae, which includes the Woods Thrush and the American Robin, and has the scientific name Sialia sialis. Blue on its head, back, tail, and wings, it has a rust-red colored breast and likes open country with scattered trees, orchards, and farmland, while it dines on insects, worms, and berries.
It may surprise some, but bluebirds actually do not migrate south for the winter months, but instead move deep into nearby forests to spend the colder months. They reappear in early spring, once the temperatures have warmed up and the blanket of snow begins to recede.
They are always welcomed by gardeners, as their diet is largely made up of insects caught on the ground, such as caterpillars, beetles, crickets, grasshoppers, and spiders. In the winter months, while they hide out in the deeper woods, they feed on large amounts of fruit, such as blueberries, black cherries, dogwood berries, and honeysuckle. They can often be seen perched on wires or fence posts overlooking open fields. They will flutter to the ground to grab an insect, or sometimes will catch their prey in midair. The boxes and tree cavities where bluebirds nest are in high demand by birds that require holes for nesting, and male bluebirds will attack other species if they are considered a threat. The male bluebird attracts a female by carrying nesting material into and out of the nest, and once the female enters the nest, the pair establishes a bond that often remains for several seasons.
Thereafter, the female does all of the nest building and may use the same nest to hatch and rear multiple broods. She will lay between two and seven eggs and may produce up to three broods throughout the season. The incubation period for the eggs is 11-19 days, and the nesting period runs from 17-21 days.
Research has shown that their populations have steadily increased since the mid-60s. While introduced species such as the European Starlings and House Sparrows have competed for existing nest holes, the development of bluebird trails and other nest-box campaigns designed to keep out the sparrows and starlings has aided bluebird recovery.
While bluebirds do not often come to typical bird feeders, they will respond well to the presentation of mealworms. Simply placing several mealworms on a plate that sits on a picnic table will attract them, and they will become regular visitors if you keep the plate well supplied.
On the other hand, adding bluebird nesting boxes to your yard may be your best opportunity to increase bluebird presence. You can find plans for building these boxes online and even watch their construction on YouTube. These boxes should be mounted 3-6 feet above the ground. Research has shown that bluebirds prefer the boxes that face east, followed by a box facing north, south, or west. Tree swallows are the greatest competitor for these boxes. To increase the possibility of their use by bluebirds, they should be put up in pairs. When erected in pairs, the more aggressive tree swallow will occupy one, but not allow other tree swallows to nest in the other, thus creating a nesting location for bluebirds. The pair of houses should be placed 15-20 feet apart, and the pairs of houses should be located 300 feet apart. Boxes should be cleaned out prior to their first use in the spring, and subsequently cleaned of all nesting material immediately after a brood leaves to encourage reuse by another brood.
Once you have established several bluebird nesting boxes, there is little effort needed to maintain them, and they will provide you a great opportunity to enjoy this beautiful bird as it nests in the boxes you have provided and feeds in your own backyard.
