LITTLE RED HERON III 
But what can one say of such an instinct—if we 
can call it an instinct ¢ It is in its essence a weakness 
in the creature similar to that of many mammals, 
birds, fishes, batrachians, reptiles and insects that 
become paralysed with fear, or rather hypnotised, 
in the presence of an enemy. A strange flaw in the 
animal, since it brings to naught all the admirable 
instincts of self-preservation it has been endowed 
with, and gives it, without a struggle, a prey to its 
enemies, even to those of a slow, sluggish disposition. 
In this particular instance the weakness or fault 
of nature has been taken advantage of by that principle 
which we call natural selection and has resulted in a 
more perfect protection than if the bird had been 
incapable of losing its mind, as one may say. In 
other words, the creature’s liability to the hypnotic 
or cataleptic state on certain occasions is its best 
protection. 
This, however, is not the only case in which a 
seemingly fatal weakness has been turned to good 
account, as we see in the death-like swoon, or “ pre- 
tending to be dead,’”’ of many creatures when over- 
come by or in the presence of an enemy. I have 
observed it in the pampas fox and opossum, in the 
Tinamu, the Partridge of South America, in our 
Corncrake, and other Rails, and I have captured 
small birds by giving them a sudden fright. 
By a strange chance I discovered that my Little 
Bittern was also subject to this weakness. A gaucho 
boy of my acquaintance, knowing that I was interested 
in this bird, one day brought me a dead specimen. 
