Eastern bluebird nesting
After a male Eastern Bluebird has attracted a female to his nest
site (by carrying material in and out of the hole, perching, and
fluttering his wings), the female does all the nest building.
She makes the nest by loosely weaving together grasses and pine
needles, then lining it with fine grasses and occasionally horse
hair or turkey feathers. Nest boxes in some places are so common
that a single territory may contain several suitable holes.
Females often build nests in each available hole, but typically
only use one of these. Bluebirds may use the same nest for
Eastern bluebird food
Insects caught on the ground are a bluebird’s main food for much
of the year. Major prey include caterpillars, beetles crickets,
grasshoppers, and spiders. In fall and winter, bluebirds eat
large amounts of fruit including mistletoe, sumac, blueberries,
black cherry, tupelo, currants, wild holly, dogwood berries,
hackberries, honeysuckle, bay, pokeweed, and juniper berries.
Rarely, Eastern Bluebirds have been recorded eating salamanders,
shrews, snakes, lizards, and tree frogs
Eastern bluebird behavior
This small, brightly colored thrush typically perches on wires
and fence posts overlooking open fields. The birds forage by
fluttering to the ground to grab an insect, or occasionally by
catching an insect in midair. Bluebirds can sight their tiny
prey items from 60 feet or more away. They fly fairly low to the
ground, and with a fast but irregular pattern to their wingbeats.
Males vying over territories chase each other at high speed,
sometimes grappling with their feet, pulling at feathers with
their beaks, and hitting with their wings. The boxes and tree
cavities where bluebirds nest are a hot commodity among birds
that require holes for nesting, and male bluebirds will attack
other species they deem a threat, including House Sparrows,
European Starlings, Tree Swallows, Great Crested Flycatchers,
Carolina Chickadees, and Brown-headed Nuthatches, as well as
non-cavity nesters such as robins, Blue Jays, mockingbirds, and
cowbirds. Males attract females to the nest with a display in
which he carries bits of nesting material into and out of the
nest. Once a female enters the nest hole with him, the pair bond
is typically established and often remains intact for several
seasons (although studies suggest that around one in every four
or five eggs involves a parent from outside the pair).