Advancing to the visitor, they place themselves
behind it; then all three, keeping step, begin a rapid march, uttering
resonant drumming notes in time with their movements; the notes of the
pair behind being emitted in a stream, like a drum-roll, while the
leader utters loud single notes at regular intervals. The march ceases;
the leader elevates his wings and stands erect and motionless, still
uttering loud notes; while the other two, with puffed-out plumage and
standing exactly abreast stoop forward and downward until the tips of
their beaks touch the ground, and, sinking their rhythmical voices to a
murmur, remain for some time in this posture. The performance is then
over and the visitor goes back to his own ground and mate, to receive a
visitor himself later on.
In the Passerine order, not the least remarkable displays are witnessed
in birds that are not accounted songsters, as they do not possess the
highly developed vocal organ confined to the suborder Oscines. The
tyrant-birds, which represent in South America the fly-catchers of the
Old World, all have displays of some kind; in a vast majority of cases
these are simply joyous, excited duets between male and female, composed
of impetuous and more or less confused notes and screams, accompanied
with beating of wings and other gestures. In some species choruses take
the place of duets, while in others entirely different forms of display
have been developed.
Pages:
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270