YPECAHA RAIL 167 
they all immediately wheel about and begin the 
exhibition. 
Whilst screaming they rush from side to side as if 
possessed with frenzy, the wings spread and agitated, 
the beak wide open and raised vertically. I never 
observed them fight or manifest anger towards each 
other during these performances; and knowing the 
pugnacious spirit of the Ypecahas, and how ready 
they are to seek a quarrel with birds of other species, 
this at first surprised me, for I was then under the 
mistaken impression that these gatherings were in 
some way related to the sexual instinct. 
Whilst watching them I also remarked another 
circumstance. When concealing myself amongst the 
rushes I have been compelled to place myself so 
disadvantageously, owing to the wet ground, that 
any single bird straying accidentally into the open 
space would have discovered my presence immed- 
iately ; yet the birds have entered and finished their 
performance without seeing me, so carried away 
are they by the emotion that possesses them during 
these moments. But no sooner has the wild chorus 
ended, than, aware of my presence, they have fled 
precipitately into the reeds. 
We frequently speak of our familiarity with the 
habits of the species we have long and carefully 
observed in a state of nature; yet the knowledge so 
gained must necessarily be exceedingly imperfect, for 
with many shy vigilant birds it is next to impossible 
to see them without being seen; and no bird, con- 
scious of being watched, will act unconstrainedly 
