While thus singing they stand facing each other, necks
outstretched and tails expanded, the wings of the first bird vibrating
rapidly to the rapid utterance, while those of the second bird beat
measured time. The finale consists of three or four notes, uttered by
the second bird alone, strong and clear, in an ascending scale, the last
very piercing.
In the melodists proper the displays, in a majority of cases, are
exclusively vocal, the singer sitting still on his perch. In the
Troupials, a family of starling-like birds numbering about one hundred
and forty species, there are many that accompany singing with pretty or
grotesque antics. The male screaming cow-bird of La Plata, when perched,
emits a hollow-sounding internal note that swells at the end into a
sharp metallic ring, almost bell-like: this is uttered with wings and
tail spread and depressed, the whole plumage being puffed out as in a
strutting turkey-cock, while the bird hops briskly up and down on its
perch as if dancing. The bell-like note of the male is followed by an
impetuous scream from the female, and the dance ends. Another species,
the common Argentine cow-bird of La Plata, when courting puffs out his
glossy rich violet plumage, and, with wings vibrating, emits a
succession of deep internal notes, followed by a set song in clear,
ringing tones; and then, suddenly taking wing, he flies straight away,
close to the surface, fluttering like a moth, and at a distance of
twenty to thirty yards turns and flies in a wide circle round the
female, singing loudly all the time, hedging her in with melody as it
were.
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