Bluebird - Sialia sialis (Linnaeus)

Bluebird - Sialia sialis (Linnaeus)

Female, immature, male Click image for Audio

OTHER NAMES:
Eastern Bluebird; Wilson's Bluebird; Blue Robin; Common Bluebird; Blue Redbreast; American Bluebird.

GENERAL DESCRIPTION:
Length, 7 inches. Upper parts, bright blue; under parts, cinnamon-chestnut and white. Bill, small and slender; wings, long and pointed, tail, shorter than wing, distinctly notched; legs, short. Color.

ADULT MALE:
Upper parts, uniform bright blue, the shafts of wing- and tail-feathers black; and tips of wing-feathers (especially primaries) dusky; sides of head including cheeks (sometimes including also chin and sides of upper throat), lighter and grayer blue; throat, chest, breast, sides, and flanks, uniform dull cinnamon-chestnut; abdomen, anal region, and under tail-coverts, white, the last with longer feathers tinged with pale grayish-blue, the shorter ones with pale cinnamon-rufous; under wing-coverts, pale grayish-blue; bill, black; iris, dark brown.

ADULT FEMALE:
Above, bluish-gray tinged with light grayish-brown (especially in autumn and winter), passing into bright blue on rump, upper tail-coverts, and tail; wings, blue, the inner quills and innermost greater coverts edged with pale brownish-gray or whitish, the outermost primary edged with white; front and lateral under parts, dull rufous-cinnamon (paler in summer, deeper in fresh autumn Plumage), the chin and upper throat paler; abdomen, anal region, and under tail-coverts. white.

NEST:
The natural nesting sites are in deserted Woodpecker holes, hollows of decayed trees, or crevices of rocks; it was one of the first birds to take advantage of " modern conveniences " and quickly appropriated boxes placed around the farm houses for its occupancy; hollows in old rail-fences are often used and in some parts of New England a large percentage of nests are so located; more rarely the pair usurp a Swallow's nest; the nest is composed of grass, weed stalks, a few bits of bark, and lined with finer grass-blades.

EGGS:
4 to 6, rarely 7 and usually 5, plain light bluish-white in color.

Distribution:
United States and southern Canada east of Rocky Mountains; north to Nova Scotia, Southern New Brunswick, southern Maine, Vermont, northern New York (Adirondacks), northern Ontario and Manitoba, occasionally to northern New Brunswick, northern Maine and southern Quebec; west to eastern base of Rocky Mountains, in Montana, Wyoming and Colorado; breeding southward to southern Florida and along the Gulf Coast to southern and west-central Texas; Bermudas (resident) ; accidental in Cuba.

This beautiful and singularly lovable bird divides with the Robin the grateful mission of bringing to its northern human friends the welcome news that spring is at hand. In the article on the Robin, it is explained that many individuals of that species remain during the winter months in northern latitudes of the United States. Few Bluebirds do this;and their appearance in the spring is, therefore, much more significant than is the Robin's. 'To be sure, the Bluebird's migratory instinct occasionally gets the better of his meteorological discretion, so that his greeting to his northern breeding grounds is sometimes a howling "north-easter," bringing snow and freezing temperatures which drive him back to the southland, or not infrequently cost him his life.
A real tragedy of this kind occurred in the spring of 1895, when many species of migratory birds, but especially the Bluebirds, were caught in the wave of severely cold weather which swept through the Middle and Gulf States. Thousands of Bluebirds perished in the storms and bitter cold which lasted for a week or more; their frozen bodies were found everywhere--in barns and other outhouses where the poor things had vainly sought shelter; in the fields and woods and even along the roadsides. In the localities affected, they were almost exterminated. To many people it was a sad spring in those regions. Such natural disasters befall the Bluebird from time to time; the cold winter of 1957-58 also saw heavy losses in the Bluebird population.
Much dubious ornithology has been produced by poets from whose minds facts are crowded out by fancies, but James Russell Lowell revealed a trained eye, as well as an appreciation of the beautiful, when he wrote (in "Under the Willows") of

The Bluebird, shifting his light load of song,
From post to post along the cheerless fence,

a pretty spring habit of the bird which has delighted many a wayfarer.
Like the Robin, the Bluebird shows a decided fondness for human society. Orchards are favorite natural resorts of the bird, and furnish plenty of home-sites in the shape of hollow trunks or limbs of trees, for the bird always prefers a cavity of some kind wherein to place its nest. The wise owner of such trees will do his utmost to encourage this tenancy. Indeed, if he will scatter through his orchard a goodly supply of Bluebird homes, in the form of short sections of hollow limbs, covered at the top and bottom, and with an auger-hole doorway, he will soon have plenty of Bluebird tenants, who will pay their rent many times over by destroying injurious insects and worms. For, with the possible exceptions of the House Wren and the Purple Martin, the Bluebird is as willing as any bird to set up housekeeping in a dwelling for him made and provided.
A bird box with a hole the diameter limited to 1 1/2 inches will ensure an opening too small for starlings but large enough for bluebirds.
The sentimental aspects of the society of Bluebirds will not be overlooked by people who appreciate manifestations of very genuine domestic peace and happiness. None of our common birds are so demonstrative in their expressions of devotion to each other, and in their affectionate solicitude for their young. The note of lament which is so plainly expressed in the Bluebird's abbreviated warble as it prepares to follow the retreating summer, brings a sympathetic echo from many a human heart.

The Bluebird has not been accused, so far as known, of stealing fruit or of preying upon crops.
An examination by the United States Biological Survey of 855 stomachs showed that 68 % of the food consisted of insects and their allies, while the other 32 % was made up of various vegetable substances and was found mostly in stomachs taken in winter. Beetles constituted 21 % of the whole food, grasshoppers 22, caterpillars 10, and various other insects, while a number of spiders and myriapods, about 6 %, comprised the remainder of the animal diet. All these are more or less harmful, except a few predacious beetles, which amounted to g % The destruction of grasshoppers by Bluebirds is very noticeable in August and September, when these insects make up about 53 % of the diet. So far as its vegetable food is concerned the Bluebird is positively harmless. The only trace of any useful product in the stomachs consisted of a few blackberry seeds, and even these probably belonged to wild rather than cultivated varieties.
The Azure Bluebird (Sialia sialis fulva) wanders over the Mexican border into Arizona. It is much like the type species, though the browns of its plumage are paler, the grayish-blue nearer a gray-white, and the blue of the upper parts greener.