Sialia Sialis
Order Passeriformes
Family Turdidae
♂ Adult male.— Entire upper parts bright blue, particularly when seen in strong light; throat, breast, and sides reddish-brown; belly whitish.
♀ Adult female.— Upper parts grayish, but in flight showing blue on the rump, wings, and tail; the reddish-brown of the under parts much paler than in the male.
Immature.— Back spotted with whitish; throat and breast whitish, mottled with brownish spots.
Nest, in a hollow limb, box, or knot-hole, lined with grass.
Eggs, light blue.
In southern Connecticut and Rhode Island, especially along the Sound, and in the lower Hudson Valley, small flocks of bluebirds spend the winter, feeding largely on berries. In most of New England and New York, however, the Bluebird is only a summer resident, common from early March through October. The breeding birds arrive soon after the first warm days of March; a little later the northern migrants are seen flying over, singly, in pairs, or in small flocks.
The Bluebird frequents country where more or less open ground is broken by low trees or bushes; an old apple orchard is a typical haunt. From some low point of vantage, a post or bough, it watches the ground, flying down at intervals to secure an insect. From the first of April, the warbling of the male becomes less frequent, and by the middle of the month the bird is comparatively silent. The female is now sitting in some hollow limb, or in a box or jar provided for her. In June the second brood is raised, and during the second mating season there is a renewal of the song. The late summer and early fall find the Bluebird in small groups, often associated with Chipping Sparrows, feeding all through the open farming country. Snatches of the spring song are now not infrequently heard, but the characteristic note of this season is the call-note, cher-wee, uttered by old and young of both sexes. When the parents are attending their young, they utter a peculiar chatter, like the syllables chut-ut-ut. The song is simple, and consists chiefly of variations on the call-note; its charm is due to the gentleness and richness of the voice, and its association with early spring.
The Bluebird should be confused with no other blue bird; the Indigo-bird is blue on the breast, while the Bird’s breast is reddish-brown; the female Bluebird is dull-colored, but both females and young show blue in flight. The Bluebird when perched looks round-shouldered, and the male nearly always flutters a wing on alighting.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)