270 The Naturalist in La Plata. 
puffed-out plumage and standing exactly abreast, 
stoop forward and downward until the tips of their 
beaks touch the ground, and, sinking their rhyth- 
mical 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. 
Dance of Spur-winged Lapwings. 
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 sub- 
order 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 
