430 



SAVAGE SUDAN 



squacco at the instant of alighting folds up those snow-white 

 wings beneath a pendent mantle of mouse-brown coverts and 

 scapulars, with the result that the bird, as by magic, vanishes 

 from view. Its sudden disappearance is startling ; but that 

 effect alone would not fulfil all the axioms. Beyond that 

 and in marked contrast with the stated habit of its white 

 congeners the squacco (i) invariably selects for alighting 

 the very spot which best lends itself to purposes of conceal- 

 ment say some patch of spiky 



%^liS^i dead reeds or grey-green flags; 



and (2), having settled, at once 

 assumes an upright pose of rigid 

 immobility. 



So exact, then, is the blend- 

 ing of the bird with its environ- 

 ment that, even should one have 

 kept an eye fixed on the precise 

 spot, it is still difficult to dis- 

 entangle that bronzy - brown 

 upright form from the bronzy- 

 green reeds that half -conceal 

 it. Were it conceivable that the 

 colour of an object were re- 

 flected in its shade, then the 

 colour of the skulking squacco 

 is precisely what one would 

 expect in the shade of sere flags 

 or grey-green reed. 



Thus the squacco heron is 

 not only conscious of the value of its concealing coloration 

 and equally of immobility but deliberately and habitually 

 avails itself of both advantages. I know of no other bird to 

 which this remark would apply with equal force ; and it is 

 written after close observation of it, and its congeners, during 

 three winters on the Nile. 



To this, Mr A. L. Butler appends the following convincing 

 corroboration : " So remarkable is the way in which this species 

 becomes invisible upon closing its wings and alighting, as you 

 describe, that in at least two Indian languages I can remember, 



SQUACCO HERONS {Ardea ralloidts). 



Availing both concealing coloration and 

 immobility simultaneously. (Note 

 that when on the wing these herons 

 appear practically white.) 



