SONG BIRDS, birds whose vocal expression resembles music. Technically the super-family Oscines, "song birds," includes nearly all the families of perching birds (Passeres), about five thousand species. Among the perching birds it excludes such groups as the Old World Pittas, and the New World flycatchers (Tyrannidae) each species of which has a characteristic word, as "phoebe," "chebec," or the more melodious "pee-wee," in place of a song. The distinguishing mark of the Oscines is the possession of four or more pairs of muscles controlling the syrinx, the organ of voice in birds; this brings within the super-family the crows and jays, many of which have rich and supple voices, some of them very human in tone, but in the more popular sense they are not "song birds" because they lack the rhythm and melody which the true songsters possess.
Many of the finest singers are found in the northern temperate zone, among the thrushes (Turdidae) and their close kindred the Old World warblers (Sylviidae), families which include the Euro pean blackbird, the song thrush, the nightingale and blackcap. The nightingale is the most famed of all song birds, though poets singing the praises of Philomela have mistaken the sex of the singer, as Milton, who speaks of "her sad song." The nightin gale's summer range extends from southern England through Europe eastward to the Balkans and Asia Minor, and southward to northwest Africa. Its song, writes Hudson, "is exceedingly beautiful; its phrasing is more perfect than that of any other British melodist ; and the voice has a combined strength, purity and brilliance probably without a parallel." In Scandinavia, Rus sia and Siberia it is replaced by the slightly larger eastern nightin gale, the bird known to Linnaeus. The blackbird, found throughout Europe, a black thrush with an orange bill, has "a beautiful mellow voice," according to Hudson, who speaks of the peculiar soft, rich melodious quality of the sound, and the placid, leisurely manner in which the song is delivered. As Browning noted, the song thrush "sings each song twice over," or, more truly, each theme or musical element of his song. The missel thrush is best known as a winter singer; from midwinter until spring, as Hudson writes, "his music is most noteworthy. Its loudness and wild character give it a wonderful impressiveness." The European robin redbreast, one of the dozen British birds so well known as to have a personal name, belongs to the same gifted family ; Burroughs has written well of his pure and piercing tones, "piercing from their smoothness, intensity, and fulness of articu lation." Among the Old World finches (Fringillidae) many are good singers; the bullfinch has the best voice, with the mellow contralto quality of the blackbird. In another musical family, the larks (Alaudidae), the skylark is pre-eminent, almost as dear to poets as the nightingale; but the best description is in Hudson's rhythmical prose : "I have listened to it by the hour, never weary ing nor ceasing to wonder at that mysterious beautiful music which was like the heavenly sunshine translated into sound; subtle, insistent, filling the world and the soul, yet always at a vast distance, falling like a lucid rain."
Some of the finest New World singers belong to the thrush family. Among the thrushes of the eastern States are the wood thrush, whose clear, bell-like tones, carrying to a great distance, are linked together by varied notes heard only near at band, some like a twanged mandolin string; the hermit thrush, still more eminent for richness of tone, melody and the expressive passion and length of his song ; the veery, whose circling choral thrills by the richness of its overtones; the gray-cheeked thrush, with a similar choral turning upward at the end; the olive-backed thrush, whose song somewhat resembles the hermit's; the robin, with a clear, happy tone and an endless variation of themes, which he embroiders together for a half hour without stopping; and the bluebird, with pure contralto tones, but less melodic power than the other New World thrushes. Many of the North American finches are gifted singers. The rose-breasted grosbeak has a rich contralto voice, a fine melodic sense, and something of the passion ate expression of the hermit thrush; unlike the robin, he sings a single, definite melody, repeated at intervals. The purple finch has contralto tones, in contrast to the high notes of the gold finches, who gather in a tree top and sing in chorus. Many American sparrows are good singers, the song sparrow being the best endowed as a melodist, almost every song sparrow having his individual song, with a marked sense of rhythm. The fox sparrow sings in early spring a clear, rich melody. The song of the white-throated sparrow has a dactyl rhythm, prefaced by one note, either above or below the monotone dactyls. The white crowned sparrow opens his song with three notes, like a higher echo of the meadowlark's song, followed by a short trill. In the family Icteridae the bobolink, whose wild, sweet rippling song is uttered as he flies across a meadow, is the best singer; the orioles, with rich tones, and expressive themes, suggest eloquent speech rather than song. The New World wood warblers (Mnio tiltidae), most of which are irrepressible singers on the spring migration, have distinctive themes, but only a few, like the water thrushes and the Canadian warbler, are melodious singers. The family to which the wrens belong (Troglodytidae) includes noted singers like the mocking bird, so famous in the songs of the South, and the brown thrasher which sings each theme twice over from a conspicuous tree top; the rock wren of the western mountains; the clear voiced Carolina wren ; the tinkling winter wren of the northern hills; and the widely distributed long-billed marsh wren, who is wafted into air by the vehemence of his song. Of the mocking birds of South America Hudson has written eloquently. Australia has gifted mockers, like the lyre-bird, but they are not true song birds. (C. JoH.)