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 
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 ralloides). 
Availing both concealing coloration and 
immobility simultaneously. (Note 
that when on the wing these herons 
appear practically white.) 
