The sun was warm but the wind was chill.
You know how it is with an April day.
When the sun is out and the wind is still,
You’re one month on in the middle of May.
But if you so much as dare to speak,
a cloud come over the sunlit arch,
And wind comes off a frozen peak,
And you’re two months back in the middle of March.
A bluebird comes tenderly up to alight
And turns to the wind to unruffle a plume,
His song so pitched as not to excite
A single flower as yet to bloom.
It is snowing a flake; and he half knew
Winter was only playing possum.
Except in color he isn’t blue,
But he wouldn’t advise a thing to blossom.
— Robert Frost, excerpt from Two Tramps in Mud Time
Eastern bluebirds are preparing for the first of the two or three broods they will raise this summer. Contrary to what those of us who clean out our bluebird boxes have been led to believe, Cornell Lab of Ornithology states that experiments show preferences for nesting boxes containing old nests. In a paired experimental design bluebirds chose boxes containing old nests in 38 of 41 cases in which boxes with old nests were paired with empty ones. Scientists conjecture that this may be because the old nests often contain wasp larvae, an easy source of food for the bluebirds.
Females build their nest over several days. Grasses and pine needles are gathered from the ground and delivered to the nest box. Fine grasses, horse hair and turkey feathers often provide the soft, innermost lining of the nest. While the male enters the box during the nest-building process, perhaps to inspect, he does not actively collect material or participate in the building of the nest. Once the 3 – 7 eggs are laid, the female spends the next two weeks or so incubating them. She then broods the young for about a week, and both parents provide them with food for up to three weeks after the young have fledged. (Thanks to Jeannie Killam and Terry Ross for photo op.)
By this time of the year fruit-eating birds have, for the most part, devoured the choicest fruits available in winter. What remains are the fruits-of-last-resort. While Staghorn Sumac fruits may not be a preferred food, they are an important source of winter sustenance for many species of birds, including bluebirds (pictured), cardinals, chickadees, jays, robins, waxwings, crows, mockingbirds and starlings. Some of the best late-winter birding occurs near stands of this shrubby relative of poison ivy. Can you find the four Eastern Bluebirds feeding on sumac in the photo?
They may not be sweet, plump and juicy, but the fruits of staghorn sumac play a crucial role in the lives of many birds that overwinter in New England. True, they’re not a preferred food for these birds, but because they persist through the winter, these fuzzy fruits are an important source of food in late winter and early spring, when very little else is available. Ruffed grouse and wild turkeys rely on sumac fruit as a source of food throughout the winter, and bluebirds, robins, cardinals, mockingbirds and starlings are frequent visitors to staghorn sumac shrubs this time of year.
Eastern bluebirds have already been seen checking out nest boxes – behavior that usually isn’t observed for another month or so. Interestingly, even though most people religiously clean out their bluebird boxes every year prior to the nesting season, experiments show that bluebirds prefer nesting boxes containing old nests. While breeding has not yet begun, it won’t be long before males will be trying to attract females to their nest site by carrying material in and out of the hole, perching, and fluttering their wings. After the males choose the nest site and perform for a mate, the females actually do the hard work of building the nest.