One of the soaring singers is a small yellow field-finch of La Plata--Sycalis luteola; and this species, like some others, changes the form of its display with the seasons. It lives in immense flocks, and during the cold season it has, like most finches, only aerial pastimes, the birds wheeling about in a cloud, pursuing each other with lively chirpings. In August, when the trees begin to blossom, the flock betakes itself to a plantation, and, sitting on the branches, the birds sing in a concert of innumerable voices, producing a great volume of sound, as of a high wind when heard at a distance. Heard near, it is a great mass of melody; not a confused tangle of musical sounds as when a host of Troupials sing in concert, but the notes, although numberless, seem to flow smoothly and separately, producing an effect on the ear similar to that which rain does on the sight, when the sun shines on and lightens up the myriads of falling drops all falling one way. In this manner the birds sing for hours, without intermission, every day. Then the passion of love infects them; the pleasant choir breaks up, and its ten thousand members scatter wide over the surrounding fields and pasture lands. During courtship the male has a feeble, sketchy music, but his singing is then accompanied with very charming love antics. His circlings about the hen-bird; his numberless advances and retreats, and little soarings above her when his voice swells with importunate passion; his fluttering lapses back to earth, where he lies prone with outspread, tremulous wings, a suppliant at her feet, his languishing voice meanwhile dying down to lispings--all these apt and graceful motions seem to express the very sickness of the heart. But the melody during this emotional period is nothing. After the business of pairing and nest-building is over, his musical displays take a new and finer form. He sits perched on a stalk above the grass, and at intervals soars up forty or fifty yards high; rising, he utters a series of long melodious notes; then he descends in a graceful spiral, the set of the motionless wings giving him the appearance of a slowly-falling parachute; the voice then also falls, the notes coming lower, sweeter, and more expressive until he reaches the surface. After alighting the song continues, the strains becoming longer, thinner, and clearer, until they dwindle to the finest threads of sound and faintest tinklings, as from a cithern touched by fairy fingers. The great charm of the song is in this slow gradation from the somewhat throaty notes emitted by the bird when ascendino-to the excessively attenuated sounds at the close.