no BIRDS OF LA PLATA 



experimenting, pressing down the bird's head and 

 trying to bend him by main force into some other 

 position ; but the strange rigidity remained unre- 

 laxed, the fixed attitude unchanged, I also found, 

 as I walked round him, that as soon as I got to the 

 opposite side and he could no longer twist himself on 

 his perch, he whirled his body with great rapidity the 

 other way, instantly presenting the same front as before. 

 Finally I plucked him forcibly from the rush and 

 perched him on my hand, upon which he flew away ; 

 but he flew only fifty or sixty yards off, and dropped 

 into the dry grass. Here he again put in practice 

 the same instinct so ably that I groped about for 

 ten or twelve minutes before refinding him, and was 

 astonished that a creature to all appearance so weak 

 and frail should have strength and endurance suffi- 

 cient to keep its body rigid and in one attitude for 

 so long a time. 



Some recent or at all events later observations 

 appear to show that some species of Bittern possess 

 a similar instinct to that of the bird described the 

 faculty of effacing themselves as it were in the presence 

 of an enemy. Doubtless any Bittern, its colouring 

 being what it is, would make itself invisible among 

 partially decayed and dead vegetation by extending 

 and stiffening its body and keeping its breast towards 

 its intruder. The peculiar thing in the case of the 

 small Heron is that the whole action of the bird 

 appears to be framed and designed expressly to make 

 it look exactly like a dead yellow tapering bulrush. 



